Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_927_Библиотеки_им_академика_М_И_Перельмана.pdf
D
M S
R T
Shar
ODUCTION
INTR
umors of the sacrum and retrorectal space are rare. Two reviews of
T
patients at the Cleveland Clinic found 50 patients between 1928 and
1985 (Table 26-1) and 87 patients between 1981 and 2011, in line with
other studies indicating that in major referral centers, 1.4 to 6.3 patients
will be diagnosed with these tumors per year. e annual incidence of
congenital retrorectal tumors is estimated to be from 0.0025% to 0.013%.
ANA
TOMY OF THE RETRORECTAL
SPACE
e retrorectal (presacral) space is a potential space that becomes
apparent only when a mass expands into it. Anatomic descriptions
ABLE 26-1:
T
umors 1929-1985
tal T
ype of tumor No.
T
hordoma 17
C
Germ cell tumors
veland Clinic: Sacral and Retrorec
Cle
-
on Grundfest-Broniatowski and Ajit Krishnaney
f the area are inconsistent because of controversy over the nomen-
o
clature of the endopelvic fascia, and in particular, the denition of
Waldeyer fascia. e most generally accepted denition describes
the retrorectal space as bounded anteriorly by the mesorectal fascia
and mesorectum, posteriorly by the presacral fascia over the sacrum
and coccyx, superiorly by the peritoneal reection, and inferiorly by
the fusion of the rectal visceral fascia and the parietal presacral fascia
over the levator ani and coccygeal muscles. Laterally, it is bounded by
the iliac vessels and the ureters (Fig. 26-1). It is divided into superior
and inferior sections by the rectosacral fascia, which passes from S2,
S3, or S4 to the rectum, inserting approximately 3 to 5 cm above the
anorectal junction where it joins the mesorectal visceral fascia. e
space normally contains loose connective tissue, the middle sacral
artery, the iliolumbar vessels, the superior and middle hemorrhoidal
vessels, lymphatics, and branches of the sympathetic and parasympathetic nervous systems. Some authors consider only the compartment superior to the rectosacral fascia to be the retrorectal space and
label the inferior compartment the supralevator space.
e embryologic hindgut and the neuroectoderm fuse in the
retrorectal space. As a result, many dierent kinds of tumors can be
found there arising from ectodermal, endodermal, neural crest, or
totipotential cells in the retrorectal space itself or from adjacent notochordal remnants, as well as cartilaginous and bony structures.
S
quamous cell carcinoma developing in a teratoma
(teratoma with malignant transformation)
dodermal sinus tumor (yolk sac tumor)
En
M
ature teratoma
T
ailgut cyst 6
Duplication cyst 1
Fibrosarcoma 1
Giant cell tumor of the sacrum 3
Aneurysmal bone cyst of the sacrum 1
Ewing sarcoma 1
Hemangiopericytoma 1
Neurogenic tumors
M
yxopapillary ependymoma
L
ipomeningocele
T
OTA L 50
1
2
13
1
2
CLASSIFIC
everal classication systems for masses in the retrorectal space
S
have been proposed. One of the most common, used by Uhlig and
Johnson, divides these masses into ve categories: (1) congenital,
ATION SYSTEMS
FIGURE 26-1 The r
Retrorectal
space
etrorectal space.
121
122
Dia
gnosis an
D ManageMent of sa
cral an
D retr
orectal
tuMors
X 26-1:
BO
ongenital/Developmental
C
Classification of Retr
Benign
evelopmental cysts, teratoma
D
Duplication cysts
Anterior meningocele
Adrenal rest tumor
lignant
Ma
C
hordoma
Teratocarcinoma
cquired Metaplastic
A
N
eurogenic
ign
Ben
Neurobroma
Schwannoma
Ganglioneuroma
lignant
Ma
euroblastoma
N
Ganglioneuroblastoma
Ependymoma
Neurosarcomas
Malignant schwannoma
sseous
O
Benign
iant cell tumor
G
Osteoblastoma
Aneurysmal bone cyst
orectal Tumors
lignant
Ma
Osteogenic sarcoma
Ewing sarcoma
Myeloma
Chondrosarcoma
ther Metaplastic
O
Benign
L
ipoma
Hemangioma
Fibroma
Leiomyoma
Endothelioma
Desmoid
lignant
Ma
iposarcoma
L
Hemangiopericytoma
Fibrosarcoma
Leiomyosarcoma
Metastatic carcinoma
ndetermined Malignant Potential
U
Ga
strointestinal stromal tumor
cellaneous
Mis
Hematoma
Abscess
(2)
inammatory, (3) neurogenic, (4) osseous, and (5) miscellaneous. ese categories were subdivided into benign and malignant by Dozois etal. Lev-Chelouche etal used four categories: (1)
benign congenital, (2) malignant congenital, (3) benign acquired,
and (4) malignant acquired. We adapted this classication, as
shown in Box 26-1. Finally, as an aid to operative planning, Papallardo etal. suggested a classication of tumors based on imaging
ndings according to the site of origin: (1) the presacral space,
(2) the sacrum or spinal cord and growing anteriorly, and (3) the
rectum and growing posteriorly. e most common lesions are
described in the following sections.
CONGENIT
AL/DEVELOPMENTAL
LESIONS
evelopmental lesions may arise from embryonic mishaps involving
D
primitive gut or neural structures.
Germ
G
be pure or mixed. e pure tumors include teratomas (mature or
immature; Fig. 26-2), yolk sac tumors (endodermal sinus tumors),
embryonal carcinomas, germinomas (histologically identical to
seminomas), and choriocarcinomas. Only teratomas and yolk sac
tumors are commonly seen in the sacrococcygeal region. All teratomas are composed of a mixture of tissue components derived from
one or more of the three embryonic germ layers (ectoderm, mesoderm, and endoderm) and contain tissue foreign to the anatomic site
of origin. Mature and immature teratomas are considered benign
but may undergo malignant transformation of a somatic tissue—for
Cell Tumors
erm cell tumors in the retroperitoneum and retrorectal space may
FIGURE 26-2 A sacrococcygeal teratoma resected from a 3-day-old girl.
example, squamous cell carcinoma originating in squamous epithelium or rhabdomyosarcoma developing in mesenchymal tissue. e
terms “mature” and “immature” reect histologic dierentiation of
teratomas.
Sacrococcygeal teratoma (SCT) is the most common presacral
tumor of the newborn, with an incidence of 1 in 23,000 to 1 in 40,000
live births. e dierential diagnosis of SCT includes lumbosacral
myelomeningocele, neuroblastoma, glioma, hemangioma, neurobroma, chordoma, leiomyoma, lipoma, and melanoma. Although it is
possible that these tumors may arise from germ cells or may represent
a form of fetus in fetu, the generally accepted theory is that they arise
rom totipotent somatic cells in the primitive knot (Hensen’s node)
f
or caudal cell mass. e American Academy of Pediatrics Surgical
Section classied these tumors according their location as follows:
ype I: Predominantly external (sacrococcygeal) with only a min-
T
imal presacral component
Type II: Presenting externally but with signicant intrapelvic
extension
Type III: Apparent externally but predominantly pelvic and ex-
tending into the abdomen
Type IV: Presacral with no external presentation; because there
are no external signs of a mass in type IV, early diagnosis may
be dicult and malignant transformation is common
T
eratomas are more frequent in females than in males (5:1), and
anomalies of the sacrum, urinary tract, or anorectum may accompany these lesions. An autosomal-dominant condition known as the
Currarino triad, now known to be associated with an MNX1 gene
mutation, was described in 1981 and consists of (1) a presacral mass
that may be a teratoma, meningocele, neurenteric cyst, or a combined
lesion, (2) an anterior sacral defect, and (3) an anorectal malformation. e usual clinical prenatal presentation of SCT is a uterine size
greater than gestational dates. Ultrasound reveals a solid or mixed
solid and cystic lesion with increased vascular ow and polyhydramnios. Placentomegaly and high output cardiac failure as a result of
tumor-associated arteriovenous stulae also may be observed. Fetal
magnetic resonance imaging (MRI) provides important anatomic
detail. e mortality rate for SCT diagnosed in the newborn is 5%
or less, but it approaches 50% when diagnosed in the fetus as a result
of complications such as tumor rupture, hemorrhage, cardiac failure,
and premature labor. us diagnosis of a fetal tumor should prompt
referral to a specialty center, where early delivery or fetal surgery may
be considered. e outcomes of open fetal procedures have only been
studied retrospectively. Results of alcohol and radiofrequency ablative procedures and open interventions for hydrops have generally
been poor, but cyst decompression to assist with delivery has been
helpful.
Neonatal SCTs are usually resected along with the coccyx, and the
rectum is carefully preserved. Type I and II lesions can usually be
resected aer delivery with the infant in the prone position. e coccyx is removed and buttock contouring reconstruction is performed.
Larger tumors may require a combined abdominal and posterior
approach or vascular control of the median sacral artery, which can
be achieved laparoscopically before posterior resection. Urologic
comorbidities are frequent (64%) in infants with SCT, and a plan
for urologic surveillance is important. Although SCTs are generally
benign, local recurrence aer resection is common. Surveillance with
digital rectal examination and ultrasound, measurement of alpha
fetoprotein levels every 3 months, and pelvic MRI yearly is recommended for at least 3 years.
In the past, malignant germ cell tumors had a dismal prognosis,
but current chemotherapy regimens have markedly improved survival, although neuropathic bladder or bowel abnormalities have
been seen in 11% to 41% of survivors. Other long-term complications
can include chronic lung disease, developmental delay, chronic bowel
dysfunction, and the need for scar revision.
Tailgut Cysts
ailgut cysts, also called retrorectal cystic hamartomas, are multilocu-
T
lar cysts whose histologic features are similar to and consistent with
derivation from aberrant remnants of the postanal gut (incomplete
involution of the embryonic tailgut). Early in fetal development, the
primitive gut extends caudal to the point where the anus develops and
then subsequently regresses. Remnants of this primitive structure may
then give rise to congenital cysts. e neurenteric canal, which connects the amnion to the yolk sac around the sixteenth day of development, may also be a source of some lesions. Tailgut cysts may be
RECTAL AND PARARECTAL REGION
FIGURE 26-3
and eosin stain ×41).
A car
cinoid tumor arising in a tailgut cyst. (Hematoxylin
123
lined by squamous, transitional, or columnar epithelium. e columnar epithelium may be ciliated or may contain mucin. Oen there
is an abrupt change from one type of epithelium to another. Muscle
bundles in the cyst wall are disorganized. Tailgut cysts lack dermal
appendages and mesenchymal derivatives other than smooth muscle,
brous tissue, and blood vessels, and they do not contain immature
elements. ese lesions may become quite large and occasionally
develop into adenocarcinomas or carcinoid tumors (Fig. 26-3). ere
is a strong female predominance (3:1), and the average age at presentation is 36 years. ese benign lesions are frequently misdiagnosed.
Patients are oen thought to have a perirectal abscess, leading to
misguided attempts at incision and drainage before denitive resection is performed. A history of recurrent abscesses or perianal stulas
without an internal opening should alert the surgeon to the possibility
of a retrorectal cystic lesion. Recurrence is frequent and is a result of
incomplete excision.
Duplication Cysts
e hindgut is the least frequent site for duplication anomalies. Presenting symptoms and signs include abdominal distention, vomiting, failure to thrive, constipation, diarrhea, and hematochezia. Two
forms of duplication cysts are recognized: (1) a limited tubular form
of duplication on the mesenteric aspect of the gastrointestinal tract
in which the epithelium may be squamous, columnar, or mixed, and
(2) a kind of abortive caudal twinning with duplication of the rectum,
anus, genitalia. Complete duplication of the colon, rectum, urinary
tract, and external genitalia is extremely rare. Associated cle vertebrae, mediastinal or intraspinal cysts, or a dorsal sinus tract may be
present. Unlike retrorectal cystic hamartomas, duplication cysts are
generally surrounded by a well-formed smooth muscle coat.
Occasionally, the tubular duplication may communicate at some
point with the intestine, leading to stagnation of intestinal contents
within the blind pouch. Gastric mucosa with stula formation and
malignant tumors have been reported in duplication cysts of the
rectum. erefore, it is suggested that the mucosa be peeled out if
the cyst cannot be removed. Some authors have reported successful
removal of duplication cysts via transanal endoscopic microsurgery.
Management of the caudal twinning anomaly is exceedingly complex. Smith classied these lesions as follows: Type 1 duplications
with two separate perineal ani, type 2 duplications with one or both
rectums terminating in a stula to the urogenital tract, and type 3
duplications with one external anus and one anal atresia in the pelvis.
Type 1 lesions may not require any treatment if the patient is asymptomatic. Patients with type 2 lesions usually present with intestinal
obstruction early in life. Duplication of the external genitalia is frequent. If one normal anus is present, the stula can be closed and the
duplication can be anastomosed to the other colon. If both colons
124
Dia
gnosis an
D ManageMent of sa
cral an
D retr
orectal
tuMors
d in a stula, a diverting colostomy should be performed, and the
en
anatomy should be ascertained by radiologic studies. In some cases,
external urinary diversion also may be required to treat incontinence.
If a functional puborectalis sling exists, the rectum may be brought
down to the perineum at a later date. Type 3 anomalies are usually
dicult to diagnose, and for that reason, patients with these anomalies oen do poorly. Treatment consists of dividing the common septum between the two lumens or excising the blind colon.
Anterior Sacral Mening
nterior sacral meningocele (ASM) is a rare form of spinal dysra-
A
ocele
phism characterized by an anterior hernia of the meningocele sac
through a sacral defect or neural foramen. e meningocele sac is
located in the presacral space and contains cerebrospinal uid and
sometimes neural elements. It may be associated with Currarino syndrome, spina bida, a tethered spinal cord, uterine and vaginal duplication, kidney or bladder malformation, perianal stula, imperforate
anus, anal atresia, or anal stenosis. Germ cell tumors and presacral
lipomas have also been associated with meningoceles. Pressure from
the ASM on the sacral nerve roots, rectum, bladder, and genitalia can
cause complaints of headache associated with bowel movements or
other straining, lower back and pelvic pain, constipation, diculties
in defecation, dysmenorrhea, dyspareunia, and urinary incontinence,
retention, or urgency. ese lesions can be mistaken for ovarian cysts.
e nding of a “scimitar” sacrum, characterized by a rounded, concave border with no bone destruction in the remaining sacrum, is
pathognomonic. ASM also can be seen in patients with Marfan syndrome or neurobromatosis, in which case the sacral foramen may
simply be widened, with the scimitar sign absent. MRI and computed
tomography (CT) scans are usually diagnostic, but if communication
with the dural sac is in doubt, myelography with metrizamide is recommended. Aspiration should be avoided because of the risk of meningitis. Treatment consists of opening the dura mater and obliterating
the neck of meningocele. is procedure usually does not require the
participation of an abdominal surgeon unless the sac is too large to
be closed securely from the posterior approach or unless a tumor is
associated with the meningocele, but the anterior approach can be
helpful. Laparoscopic approaches have also been described.
usually palpable, but it is dicult to assess the size of the tumor upon
digital examination. Radiographs of the pelvis will show abnormalities such as sacral bone erosion or calcication in approximately 50%
of patients. CT scanning and MRI give an accurate assessment of the
size of the mass and bone invasion (Fig. 26-4).
Five-year survival is between 47% and 80%, and approximately
20% of patients who undergo surgical resection have a recurrence at
1 year. e incidence of metastases has been reported to be between
4% and 43%. Distant disease usually involves bone or the lungs, but
it can also appear in the liver and so tissues. Median survival aer
the development of metastasis is approximately 11 months. Until
recently, the only recommended treatment was complete surgical
excision whenever possible, but obtaining tumor-free margins in
the sacrococcygeal area can be challenging and may result in neurogenic dysfunction. Intralesional excision has high recurrence rates.
Chordomas are refractory to conventional photon radiotherapy at
doses less than 60 Gy; however, in a retrospective analysis, Moojen
et al found that patients with incomplete resections who underwent direct postoperative radiotherapy had a longer tumor-free
survival than did patients with complete resections who did not
undergo radiotherapy. us postoperative radiotherapy is currently
recommended.
One promising new approach to treatment is carbon ion radiotherapy, which has shown markedly higher local control rates with
low toxicity. Authors of a retrospective study from Japan who compared carbon ion radiotherapy alone versus surgical resection without use of postoperative radiation found fewer local recurrences and
wound problems, better urinary and bowel function, and similar disease-free survival rates in the radiotherapy group. A number of other
treatments such as implantation of radioactive iodine-125 seeds and
cryoablation have been reported to assist in local control (Fig. 26-5).
Cytotoxic chemotherapy has generally had a dismal record in this disease, although some remissions have been reported with ifosfamide
or etoposide/cisplatin/vincristine/cyclophosphamide/actinomycin
D. Newer therapeutic approaches are on the horizon. A variety of
therapeutic targets have been identied, including the notochord
developmental factor, brachyury, platelet-derived growth factor
receptor-β, and inhibitors of receptor tyrosine kinase. Some modest
improvement has been reported with imatinib mesylate (a tyrosine
kinase inhibitor). Other areas suggested for investigation have been
doma
Chor
hordomas are malignant tumors thought to derive from remnants
C
of the fetal notochord. Normally, the notochord is manifest in the
adult as the nucleus pulposus of the intervertebral disks, but rests of
notochordal tissue may remain in ectopic positions. Approximately
300 cases per year are diagnosed in the United States. Chordomas
represent approximately 1% to 5% of primary bone tumors and less
than 1% of all central nervous system tumors. Fiy percent to 60%
occur within the sacrococcygeal area, and they constitute more than
50% of primary tumors of the sacrum. Other common sites include
the base of the skull and the vertebrae. Most series have noted a male
predominance for the sacrococcygeal lesions, with a ratio of approximately 2:1. Although they may occur at any age, the greatest incidence is between the ages of 40 to 70 years.
Chordomas are slow growing, locally aggressive, and resistant
to radiotherapy. ey may be gelatinous or rm, depending on the
amount of mucinous material present. Hemorrhage and necrosis may
lead to cyst formation or secondary calcication. A pseudocapsule is
oen present, and invasion of bone frequently occurs. Microscopically, one sees a lobular framework with brous septa containing
variable amounts of vacuolated physaliferous cells and extracellular
mucin.
Common presenting complaints include buttock or back pain,
numbness in the perianal region, buttock, or leg, diculty voiding,
and constipation. Muscle weakness is also frequent. Rectal masses are
FIGURE 26-4 A chor
and filling the pelvis.
doma. The tumor is eroding through the sacrum
RECTAL AND PARARECTAL REGION
125
idermal growth factor receptor inhibitors, c-Met inhibitors, and
ep
hedgehog inhibitors.
Osseous T
T
umors that primarily involve bone may arise from cartilage, bone,
umors
brous tissue, or marrow. A list of the more common tumors that can
involve the sacrum is found in Box 26-2.
Giant cell tumors usually arise in the third and fourth decades
of life. Although they have a predilection for the epiphyses of long
bones, they are not rare in the sacrum. Approximately 10% of these
lesions behave in a malignant manner. ey are radiolucent on radiographs and may produce thinning and expansion of the overlying
cortex. Adjacent so tissues also may be involved. Grossly, these
tumors are reddish-gray with areas of necrosis. Microscopically, one
nds numerous multinucleated giant cells within a brous stroma.
Algorithm 1
Reactive bone formation is common and may lead to a mistaken
diagnosis of osteosarcoma. e histologic appearance can vary
greatly within these tumors. erefore, extensive sampling is necessary to determine whether a given lesion is malignant. e usual
treatment of choice is wide resection. Radiation is not benecial and
may induce malignant change. Sarcomas have also been noted aer
surgical resection without radiotherapy. Metastases are characterized
by a “benign” histologic appearance. e most common site for metastatic disease is the lungs.
Aneurysmal bone cysts are benign lesions that may recur if
they are incompletely removed. ey are more common in patients
younger than 20 years. ese tumors may also contain foci of benign
giant cells, but they are characterized by prominent blood-lled
spaces. is lesion may be treated by local curettage and does not
metastasize.
Osteoid osteomas are considered to be benign lesions. ey usually occur during the rst or second decade of life and are more
Symptoms
(pain, pressure,
obstructed labor)
Physical examination
(visible or plapable
mass)
Retrorectal
mass
Imaging (CT,
MRI, TRUS)
Cystic lesion
Meningocele
Ligate dura
Yes No
Excise via posterior
approach ±
coccygectomy
A
FIGURE 26-5 Alg
Anteroposterior; CNS, central nervous system; CT, computed tomography; MRI, magnetic resonance imaging; TRUS, transrectal ultrasonography.
orithmic approaches to diagnosis and management of sacral and retrorectal tumors. AP,
Developmental
cyst
Below S3
<3 cm
Excise via anterior or
combined AP approach ±
coccygectomy
Consider laproscopy
Solid or mixed
lesion
Go to Algorithm
2
Continued
Algorithm 2
Benign
neural tumor
Stable, reimage
B
Algorithm 3
Benign <5 cm,
asymptomatic
Serial MRI
in 1 year
Rapid growth
in 1 year
Yes
Posterior
approach
Biopsy
solid tumor
Benign, <5 cm,
symptomatic
Consider
resection
Below S3
<3cm
tumor above S3
benign <5 cm
Yes
Resection via
No
Anterior or
combined AP
approach
Malignant
Malignant or
Resectable,
below S3
AP approach
No
Go to
Algorithm 3
Consider
radiotherapy
for malignant
tumor
Heavy ion or proton
radiotherapy
Consider neo-
adjuvant therapy
En bloc or
palliative
resection
C
FIGURE 26-5,
cont’d
Unresectable or
resectable chordoma
Resection with anterior or laproscopic
approach, or laminectomy and
combined AP approach
Consider preoperative embolization or
vascular ligation of middle sacral and
CNS involvement
Resectable
internal iliac arteries
S3 nerve root
preserved?
No
Colostomy and
en bloc
resection
Metastatic
disease?
No
Yes
resection
En bloc
Yes
En bloc
resection with
AP approach
Systemic
therapy
Restage after
treatment
En bloc or
palliative
resection
X 26-2:
BO
enign
B
Osteochondroma
Giant cell tumor
Osteoid osteoma
Eosinophilic granuloma
Chondroblastoma
Osteoblastoma
M
C
hondrosarcoma
Fibrosarcoma
Osteosarcoma
Ewing tumor
Fibrous histiocytoma
Lymphoma
Myeloma
co
mmon in males. e most common presenting symptom is moderate to intense pain that is usually relieved by aspirin. On radiographs
they appear as a central radiolucent defect, surrounded by a dense
ring of sclerotic bone. Resection or curettage is curative. Malignant
bone tumors are generally treated by wide resection when feasible,
which is oen combined with adjunctive chemotherapy or radiotherapy. e most common malignant neoplasm of bone is the osteosarcoma. Characteristically, radiographs show lytic areas accompanied
by subperiosteal new bone formation. Histologically, osteosarcomas
may demonstrate not only malignant bone cells (osteoblasts) but also
areas of malignant cartilage and brous tissue. Pulmonary metastases
are common.
Common
alignant
Sacral Tumors
RECTAL AND PARARECTAL REGION
elated to the site and size of the tumor. Rarely, hypoglycemia has
r
been reported in association with these lesions. e biologic behavior
is dicult to predict. Estimates of prognosis are based on tumor size,
cellular anaplasia, hemorrhage, necrosis, and mitotic activity. Tumors
that have more than four mitoses per high-power eld, tumors
greater than 6.1 cm in their greatest dimension, and tumors with
necrosis or hemorrhage have an increased rate of metastasis. ere
is no evidence that radiotherapy or chemotherapy aects survival. As
with most of the other lesions mentioned, the treatment is surgical
excision.
INFLAMMA
I
nammatory lesions can usually be diagnosed by history and physical examination. In the 1940s, when sclerosing injection of oil-based
phenol solutions was popular as a treatment for hemorrhoids, it
was not unusual to nd retrorectal inammatory masses as a result
of lipid granulomas. ese masses were usually treated with heat or
curettage. Such lesions are uncommon today, although rarely, perforation of the posterior rectal wall during the performance of a barium
enema can lead to a chronic inammatory mass. If the injury is recognized at the time of perforation, the patient should be treated with
a diverting colostomy, lavage of the presacral space, and insertion of
drains. Postpartum hematomas in the retrorectal space may calcify
and be confused with tumor. Of course, the most common inammatory lesion is the perianal abscess, which is usually apparent from
the history of fever and pain. Any recurrent abscess without an internal opening must be suspected to be a retrorectal tumor. A CT scan
should be helpful in making the diagnosis in such cases.
ASTATIC LESIONS
MET
TORY LESIONS
127
Neur
ogenic Tumors
pproximately 5% to 15% of tumors in the retrorectal space are
A
neurogenic tumors. Excision is generally curative. e most frequent neurogenic tumor is the ependymoma, which is classied as
ependymomas and anaplastic ependymomas, with the former being
further subdivided into myxopapillary, papillary, and subependymoma variants. Myxopapillary tumors usually arise near the cauda
equina but also may be found in the presacral space or in the dermal
tissues of the sacrococcygeal area without any apparent connection
to the spinal cord or lum terminale. ey show a predilection for
males and may occur at any age. Back pain is the most frequent
presenting symptom. Metastases occur in about 17% of patients and
may involve the subarachnoid space or the lungs. If the lesion is
well encapsulated and can be totally excised, a long survival can
be anticipated. Tumors that cannot be completely removed have a
higher rate of recurrence and a shorter survival period. Radiotherapy may be palliative. Other malignant neurogenic tumors that may
occur in this area are neuroblastomas, malignant schwannomas,
and ganglioneuroblastomas.
The neurilemmoma is a rare benign lesion that usually causes
symptoms because of its bulk. Occasionally, it can cause sacral
bone destruction by pressure erosion. Complete excision is
curative.
Nonosseous
ther so tissue tumors that may involve the retrorectal space
O
include chondromyxosarcomas, lipomas, liposarcomas, leiomyomas,
and leiomyosarcomas.
Vascular lesions in the retrorectal space can include hemangioendotheliomas and hemangiopericytomas. Hemangiopericytomas can
occur at any age and have no sex predilection. Symptoms usually are
Mesenchymal Tumors
Lymphomas, myelomas, and adenocarcinomas all can involve the
retrorectal space. Generally, this is part of a diuse disease process,
and the diagnosis is obvious. Occasionally a myeloma may be present
only in the retrorectal space.
GNOSTIC APPROACHES TO
DIA
SACRAL AND RETRORECTAL TUMORS
Symptoms of sacral and retrorectal tumors are variable and depend
on the size and location of the tumor. Tumors are more frequently
diagnosed in women and can appear at any age. Infants usually present with externally visible sacrococcygeal masses that are prone to
malignant transformation. In adults, the majority of lesions are
benign and asymptomatic. Common symptoms are pain, a feeling of
pressure or heaviness in the pelvis or rectum, or a change in bowel
habits. Small developmental cysts may be asymptomatic for years,
whereas larger cysts can result in symptoms of incomplete evacuation of stool or obstructed labor. Infection is common and can cause
pain, fever, chills, and drainage. Such lesions may be mistaken for
anorectal, pilonidal, or pelvic abscesses. Neurologic symptoms of
perianal or lower extremity paresthesia, urinary retention, or incontinence should raise suspicion for malignancy. Sometimes tumors are
seen serendipitously on a scan ordered for obscure symptoms or for
follow-up of other conditions.
Lesions in this area require a multidisciplinary approach to
diagnosis, staging, and therapy. The preoperative workup should
include a thorough physical examination including digital rectal
examination, neurologic examination, and a proctosigmoidoscopy. Although retrorectal tumors may be felt on rectal examination, assessment is greatly aided by transrectal ultrasound,
computerized axial tomography of the pelvis, abdomen, and lungs,
MRI scans, and sometimes technetium-99 bone scans. Such tests
are necessary to determine the size, extent, and composition of
128
Dia
gnosis an
D ManageMent of sa
cral an
D retr
orectal
tuMors
hese tumors. These tests also can detect invasion of tissue planes
t
and adjacent organs. Ultrasound is particularly useful for evaluation of preterm fetuses. Cysts appear hypointense on T1-weighted
MRI images and hyperintense on T2-weighted images. A cystic
lesion with a smooth, well-circumscribed margin and no signs
of invasion or enhancement with gadolinium is almost always
benign, whereas a heterogeneous or solid tumor with an irregular
margin is likely malignant. When signs of neurologic impairment
or bone invasion are seen, the surgeon should suspect malignant
disease, and an orthopedic surgeon or a neurosurgeon should be
consulted.
A biopsy is contraindicated for cystic lesions that could be meningoceles. e role of a preoperative biopsy for solid retrorectal lesions
is controversial, but preoperative biopsy of solid tumors has a higher
concordance with postoperative disease than does imaging. It is generally agreed that a biopsy specimen should not be obtained through
a transvaginal or transrectal route in order to avoid infection and
possible seeding of tumor along the needle tract, although growth of
tumor along a needle tract is very rare.
Biopsy specimens of perineal tumors may be obtained through
a longitudinal midline posterior incision to facilitate needle biopsy
through a posterior route. For bony tumors, a limited amount of
posterior cortex of the sacrum is removed and a biopsy specimen
is obtained. Given the characteristic appearance of many lesions on
MRI, a routine preoperative biopsy oen may be avoided except when
it will aect preoperative planning or in cases of suspected metastatic
disease or lymphoma.
OPERA
A
s previously noted, there have been some promising advances in
TIVE APPROACHES
radiotherapy techniques and in chemotherapy, but surgical excision
remains the treatment of choice for most tumors. Surgical excision
may involve colorectal surgeons, general surgeons, neurosurgeons,
or orthopedic surgeons, and patients benet from multidisciplinary
consultation. Treatment details depend on the type of tumor, its
histologic grade, and the presence or absence of regional or distant
metastases.
In general, tumors less than 3 cm in diameter and below the mid
body of S3 can be removed through a perineal approach. If imaging
shows a highly vascular lesion, preoperative arterial embolization is
recommended to minimize blood loss. Aer preoperative mechanical and antibiotic bowel preparation, a spinal or general anesthetic is
administered and the patient is placed in the prone jackknife position. e buttocks are spread apart, and the operative site is prepared.
A transverse or a vertical presacral incision is then made over the
coccyx. In most cases, coccygectomy is performed to facilitate access,
although Abel etal have described a parasacrococcygeal approach.
e anococcygeal ligament is divided transversely. If necessary, further exposure is achieved by detachment of the gluteus maximus
muscle from its sacral attachments. Mobilization of the tumor can
then be carried out with relative ease. Using head-down tilt of the
table and lighted retractors, the cephalad portion of the tumor can
be delivered. It is always preferable to remove benign cystic lesions
intact, but if the lesion is dicult to remove, aspiration may collapse
the cyst enough to allow easier dissection, especially of the anterior
attachment. e wound is then closed in layers over a closed suction
drain.
Indications for a combined anterior and posterior approach
include tumors above S3, size larger than 3 to 4 cm, bone erosion,
and symptoms or signs of nerve compression. Wide excisions may be
very hazardous if performed solely through the posterior approach.
e anterior dissection is performed rst (Fig. 26-6). Traditional
anterior approaches have been augmented by the development of
laparoscopic and robotic techniques when there does not appear to
be invasion of adjacent structures. e magnication available with
the endoscopic approach can facilitate nerve identication, and the
pneumoperitoneum may reduce blood loss and assist in dissection
of tissue planes. In some cases in which the tumor has no signicant
posterior component, the anterior approach can be combined with
the biopsy. If the frozen section demonstrates a benign tumor such
as an aneurysmal bone cyst, an intralesional excision can then be
performed, negating the necessity for a posterior dissection. During
the anterior dissection, the full extent of the tumor can be seen. e
rectum is mobilized out of the sacral hollow, and the middle sacral
artery and vein are ligated. Control of the internal iliac artery and
vein is achieved with vessel loops to decrease blood loss. If a diverting
AB
FIGURE 26-6 F
toneum is incised to ligate the mid
vascular, ligation of the posterior branches of the internal iliac artery and vein may be performed at this time.
or large retrorectal and sacral tumors, the anterior dissection is performed first. The rectosigmoid is mobilized, and the retroperi
dle sacral artery and vein. The internal artery and vein are surrounded by vessel loops. If the tumor is exceedingly
Middle sacral
artery
Right internal
iliac
-
RECTAL AND PARARECTAL REGION
129
lostomy is necessary, it can be performed during this phase of the
co
surgery. Depending on the extent of the tumor, the resection can
then be performed either in one or two stages. If the resection is to
be performed in two stages, the wound is then closed and a subsequent operation is scheduled in 3 to 7 days. If, however, the anterior
approach is not overly time consuming and the patient is in good
physical condition, the posterior phase of the surgery is usually performed while the patient is still anesthetized.
It is important that the posterior approach be extensive enough
to provide good visualization of the sacrum, blood vessels, and
major neurologic structures. A previous biopsy scar is totally excised
with the incision, and the skin surrounding the scar is included in
the resected specimen (Fig. 26-7). e incision is begun at approximately the level of L4 and extended distally to the level of the junction of the coccyx and sacrum. Lateral extensions of the incision are
made in line with the ber of the gluteus maximum muscle in the
direction of the greater trochanters. e dissection is then carried
deeper through the gluteal fascia, and the bers of the gluteus maximus are split, identifying the piriformis muscle (Fig. 26-8). e
piriformis tendon is transected, and the muscle is retracted immediately. If muscle invasion is suspected, then a portion of the gluteus
maximus must also be removed. At least 2 cm should be removed
along with the specimen on all sides to achieve a wide margin. e
sciatic nerve and the nerve supply to the gluteus maximus can be
visualized aer mobilization of the piriformis muscle. is visualization allows transverse sectioning of the gluteus maximum to be
performed without sacricing its nerve supply. e sacrospinous
and sacrotuberous ligaments are divided under direct vision as far
laterally as possible (Fig. 26-9). e neurosurgeon or orthopedist
will then enter the spinal canal at about the L5 level and inspect the
canal for tumor extension (Fig. 26-10). e level of the sacral resection will have been previously determined by scanning techniques
and observations obtained during the anterior approach. e laminectomy is continued distally so as to resect the bone one segment
above the old cephalad portion of the tumor. e spinal roots to be
saved are identied, and then an osteotome is placed distal to the
root and a V-shaped osteotomy is performed. During this maneuver,
the anterior structures are protected by a large pack. e anterior
FIGURE 26-7
tumors.
level of L4. Distally the incision is carried to the junction of the sacrum
and coccyx. Lateral extensions are then made toward the greater
trochanters of the femurs.
FIGURE 26-8 The gluteal fascia is divided,
maxim
The posterior a
The biopsy scar is ellipsed and carried up to approximately the
us are split. The piriformis tendon is transected.
pproach to sacral and retrorectal
and the fibers of the gluteus
FIGURE 26-9
divided under dir
FIGURE 26-10 A laminectom
to S1 if necessar
The sacr
ect vision.
y.
ospinous and sacrotuberous ligaments are
y is begun at L5 and is continued distally
130
Dia
gnosis an
D ManageMent of sa
cral an
D retr
orectal
tuMors
FIGURE 26-11
The tumor is r
the sacral segment abo
ngitudinal ligament is usually divided and mobilized during the
lo
emoved by making an osteotomy through
ve the tumor. Severed nerve roots are clipped.
anterior dissection, and the blood vessels, having previously been
controlled by preoperative embolization or by being tied and clipped
during the anterior phase of the surgery, should present no problems. e remaining fascial and muscular structures are then divided
through the posterior approach, and the specimen is removed (Fig.
26-11). Severed nerve roots are surgically clipped to prevent spinal
uid leaks. e anterior pack is then removed through the posterior
incision, and hemostasis is achieved. If postoperative radiation therapy is planned in women of childbearing age or younger, then the
ovaries are mobilized during the anterior phase of the operation and
moved out of the projected radiation eld. Multiple suction drains
are inserted, and the gluteal muscles are reapproximated. e skin is
then closed in a routine fashion over the drains, which are kept in
place until the daily output is less than 60 mL/day. e drains should
not be removed too early lest a seroma form, which may become
infected. e day aer surgery the patient is allowed to sit at the bedside, and the patient is then progressively allowed to walk during the
next 3 to 7 days. e bladder is drained with a Foley catheter, and in
persons with large resections, this catheter is removed on the h to
seventh day. A low-residue diet is prescribed.
SUMMAR
R
etrorectal tumors are rare, but important. Management is aided by a
Y
multidisciplinary approach. Malignant retrorectal tumors can be differentiated from benign lesions on the basis of history, physical examination, and the presence of neurologic or bony involvement. Cystic
lesions and anterior spinal meningoceles can be diagnosed by their
characteristic sacral deformity on radiographs, as well as by a CT scan
or MRI, and should not undergo biopsy. For solid lesions, a biopsy
may be performed through a posterior approach, and the biopsy site
can be excised during subsequent resection. Carbon ion radiotherapy
appears to have promising results for chordomas but is not yet widely
available. An aggressive surgical approach is generally warranted
for malignant tumors, even if it means sacricing nerve roots that
could impair continence, potency, and ambulation. Recurrent tumor
causes neurologic dysfunction in any case and almost always causes
the death of the patient. e outlook for malignant germ cell tumors
has markedly improved with advances in chemotherapy. Mature teratomas and tailgut cysts usually have an excellent prognosis if they are
completely excised. Most bony tumors are widely excised wherever
possible, although aneurysmal bone cysts may be treated by intralesional excision.
S
u
g g e
el ME, Nelson R, Prasad ML, et al. Parasacrococcygeal approach for
Ab
the resection of retrorectal developmental cysts. Dis Colon Rectum.
1985;28:855–858.
Altman RP, Randolph JG, Lilly JR. Sacrococcygeal teratoma: American
Academy of Pediatrics Surgical Section survey—1973. J Pediatr Surg.
1974;9:389–398.
Ashley WW Jr, Wright NM. Resection of a giant anterior sacral meningocele
via an anterior approach: case report and review of literature. Surg Neurol.
2006;66:89–93.
Baratti D, Gronchi A, Pennacchioli E, etal. Chordoma: natural history and
results in 28 patients treated at a single institution. Ann Surg Oncol.
2003;10:291–296.
Ben-Ishay O, Person B, Eran B, etal. Rectal duplication cyst in adults treated
with transanal endoscopic microsurgery. Tech Coloproctol. 2011;15:469–471.
Bruny J, Crombleholme TM. Perinatal management of infant tumors and the
promise of fetal surgery. Curr Opin Pediatr. 2013;25:31–39.
Bullard Dunn K. Retrorectal tumors. Surg Clin North Am. 2010;90:163–171.
Bydon M, Papadimitriou K, Witham T, et al. Novel therapeutic targets in
chordoma. Expert Opin er Targets. 2012;16:1139–1143.
Clatterbuck RE, Jackman SV, Kavoussi LR, Long DM. Laparoscopic treat-
ment of an anterior sacral meningocele. Case illustration. J Neurosurg.
2000;92:246.
Cooksey G, Wagget J. Tubular duplication of the rectum treated by mucosal
resection. J Pediatr Surg. 1984;19:318–319.
Cost NG, Geller JI, Le LD, etal. Urologic co-morbidities associated with sac-
rococcygeal teratoma and a rational plan for urologic surveillance. Pediatr
Blood Cancer. 2013;60:1626–1629.
Currarino G, Coln D, Votteler T. Triad of anorectal, sacral, and presacral
anomalies. AJR Am J Roentgenol. 1981;137:395–398.
Diaz RJ, Cusimano MD. e biological basis for modern treatment of chor-
doma. J Neurooncol. 2011;104:411–422.
Dozois EJ, Marcos MDH. Presacral tumors. In: Beck DE, Roberts PL, Sacalar-
ides TJ, etal, eds. e ASCRS Textbook of Colon and Rectal Surgery. 2nd
ed. New York: Springer Science + Business Media, LLC; 2011:359–374.
Farkas AM, Quevedo-Bonilla G, Gingold B, etal. Presacral hematomas. diag
osis and treatment. Dis Colon Rectum. 1987;30:130–132.
n
Fassett DR, Schmidt MH. Lumbosacral ependymomas: a review of the manage-
ment of intradural and extradural tumors. Neurosurg Focus. 2003;15:E13.
Fishman SJ, Jennings RW, Johnson SM, Kim HB. Contouring buttock
econstruction aer sacrococcygeal teratoma resection. J Pediatr Surg.
r
2004;39:439–441.
Garcia-Armengol J, Garcia-Botello S, Martinez-Soriano F, et al. Review of
the anatomic concepts in relation to the retrorectal space and endopel-
vic fascia: Waldeyer’s fascia and the rectosacral fascia. Colorectal Dis.
2008;10:298–302.
Hartmann KE, McPheeters ML, Chescheir NC, et al. Evidence to inform
decisions about maternal-fetal surgery: technical brief. Obstet Gynecol.
2011;117:1191–1204.
Hjermstad BM, Helwig EB. Tailgut cysts. Report of 53 cases. Am J Clin Pathol.
1988;89:139–147.
Hobson KG, Ghaemmaghami V, Roe JP, et al. Tumors of the retrorectal
space. Dis Colon Rectum. 2005;48:1964–1974.
Hocking M, Young DG. Duplications of the alimentary tract. Br J Surg.
1981;68:92–96.
Iyer RS, Khanna PC. Currarino syndrome. Pediatr Radiol. 2010;40(suppl 1):
S102.
Jabre A, Ball JB Jr, Tew JM Jr. Anterior sacral meningocele. current diagnosis.
Surg Neurol. 1985;23:9–13.
Jao SW, Beart RW Jr, Spencer RJ, etal. Retrorectal tumors. Mayo Clinic expe-
rience, 1960-1979. Dis Colon Rectum. 1985;28:644–652.
Jeon BC, Kim DH, Kwon KY. Anterior endoscopic treatment of a huge
anterior sacral meningocele: technical case report. Neurosurgery.
2003;52:1231–1233.
Jin ZM, Peng JY, Zhu QC, Yin L. Waldeyer’s fascia: anatomical location and
relationship to neighboring fasciae in retrorectal space. Surg Radiol Anat.
2011;33:851–854.
Kim AY, Yoo SY, Kim JH, et al. Currarino syndrome: variable imaging
features in three siblings with HLXB9 gene mutation. Clin Imaging.
2013;37:398–402.
Kovalcik PJ, Burke JB. Anterior sacral meningocele and the scimitar sign.
Report of a case. Dis Colon Rectum. 1988;31:806–807.
Kurup AN, Woodrum DA, Morris JM, etal. Cryoablation of recurrent sacro-
coccygeal tumors. J Vasc Interv Radiol. 2012;23:1070–1075.
S t
e d
e
R
a d i n g
-