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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6009_Библиотеки_им_академика_М_И_Перельмана.pdf
Terminal Myelocystocele
KEY FACTS
TERMINOLOGY
• Synonym: Terminal syringocele
IMAGING
• Complex spinal malformation → closed spinal dysraphism,
large skin-covered back mass
• Hydromyelic, low-lying tethered spinal cord traverses dorsal
meningocele and terminates in dilated terminal cyst
(myelocystocele)
• Multiplanar MR best demonstrates constellation of
abnormalities
Congenital and Genetic Disorders
TOP DIFFERENTIAL DIAGNOSES
• Anterior sacral meningocele
• Simple dorsal meningocele
• Sacrococcygeal teratoma
• Myelomeningocele
(Left) Sagittal graphic displays
a low-lying, hydromyelic spinal
cord piercing an expanded
subarachnoid space
(meningocele ſt), terminating
in a myelocystocele . (Right)
Sagittal T1WI MR depicts a
low-lying hydromyelic spinal
cord traversing a
meningocele and expanding
into a large terminal cyst.
Note the dorsal fibrous band
ſt. Note that the back mass is
caused by both the
meningocele and
myelocystocele in this case.
PATHOLOGY
• Results from deranged secondary neurulation of caudal cell
mass
• Associated malformations: Cloacal exstrophy, imperforate
anus, omphalocele, pelvic deformities, equinovarus,
ambiguous hypoplastic genitalia, and renal abnormalities
CLINICAL ISSUES
• Presents at birth with large skin-covered back mass
• Usually neurologically intact at birth; may later develop
lower extremity sensorimotor deficits
DIAGNOSTIC CHECKLIST
• Early diagnosis and surgery → best chance for normal
neurological outcome
• Nonneurological prognosis largely linked to severity of
associated anomalies
110
(Left) The spinal cord is low
lying with caudal extension of
the attenuated cord st
through a sacral cyst
(meningocele). The terminal
spinal cord flares into a 2nd
terminal cyst ſt within the
meningocele, completing the
terminal myelocystocele
malformation. (Right) Sagittal
T1WI MR shows a central
canal of low-lying cord
traversing the meningocele st
before expanding into a large
terminal cyst ſt. Note
"trumpet" splaying of the
terminal spinal cord. There is
an associated Chiari 1
malformation .
Anterior Sacral Meningocele
KEY FACTS
Congenital and Genetic Disorders
TERMINOLOGY
• Anterior sacral meningocele (ASM)
• Sacral meninges herniate anteriorly into pelvis through
focal erosion or hypogenesis of sacral ± coccygeal vertebral
segments
IMAGING
• Presacral cyst, contiguous with thecal sac through anterior
osseous defect
• Deficient sacrum ± curved (scimitar) shape
TOP DIFFERENTIAL DIAGNOSES
• Sacrococcygeal teratoma
• Sacral chordoma
• Neurenteric cyst
• Cystic neuroblastoma
• Ovarian cyst
PATHOLOGY
• Currarino triad: Anorectal anomalies, caudal regression
syndrome, epidermoid/dermoid tumor or other tethering
lesion
• Associated with conditions where dural ectasia is
prominent (neurofibromatosis type 1, Marfan syndrome,
homocystinuria)
CLINICAL ISSUES
• Constipation, urinary frequency, incontinence,
dysmenorrhea, dyspareunia, low back/pelvic pain
DIAGNOSTIC CHECKLIST
• Continuity of cyst with thecal sac necessary to ensure ASM
diagnosis
• Soft tissue mass or calcification implies tumor
• Imaging recommendations
○ Ultrasound for NICU infant screening; MR to confirm
presacral cyst location and characterize contents
(Left) Sagittal graphic (L)
depicts the characteristic
anterior sacrum "scimitar"
remodeling by a large anterior
meningocele cyst ſt. Coronal
graphic (R) shows an anterior
sacral meningocele cyst origin
through an enlarged neural
foramen . (Right) Midline
sagittal T2WI MR
demonstrates the classic
relationship of characteristic
"scimitar sacrum"
configuration with the
adjacent anterior sacral
meningocele ſt.
(Left) Sagittal T2WI MR
obtained off-midline
parasagittal shows a large
anterior presacral cyst ſt
contiguous with the meninges,
extending from the thecal sac
into the pelvis through an
enlarged neural foramen .
(Right) Axial T2WI MR
confirms unilateral left sacral
neural foraminal enlargement
permitting ventral
herniation of the meninges
into the pelvis to form a classic
anterior sacral meningocele
ſt.
111
Occult Intrasacral Meningocele
KEY FACTS
TERMINOLOGY
• Spinal extradural arachnoid cyst (AC) located within sacrum,
caudal to thecal sac termination
○ Sacral meningeal cyst, type IB meningeal cyst
• Synonym: Occult intrasacral meningocele
IMAGING
• Smooth enlargement of sacral spinal canal
○ Expands but does not transgress sacrum margins
○ No expansion or remodeling of neural foramina
• Posterior sacral vertebral scalloping characteristic
Congenital and Genetic Disorders
• No cyst wall enhancement
TOP DIFFERENTIAL DIAGNOSES
• Tarlov cyst
• Dorsal spinal meningocele
• Dural dysplasia
(Left) Sagittal graphic of the
lumbosacral spine
demonstrates an extradural
cyst ſt within the sacral
spinal canal below the thecal
sac termination at S2. Note
osseous remodeling of the
sacral spinal canal margins.
(Right) Sagittal T1WI MR
demonstrates a small fluid
signal extradural cyst in the
sacral spinal canal ſt. The
location is typical for occult
sacral meningocele, now
designated an extradural
arachnoid cyst. No solid tissue
or fat is detected within the
cyst.
PATHOLOGY
• Diverticulum of sacral subarachnoid space expands into
sacral cyst with secondary remodeling of sacral canal
• Extradural arachnoid cyst; no meningeal herniation (not
true meningocele)
• Cyst is connected to thecal sac by thin pedicle
• No neuronal elements within cyst
CLINICAL ISSUES
• Usually asymptomatic; incidental discovery on MR
○ Asymptomatic patients need no specific treatment
○ Indications for operation include ↑ cyst size on serial
exams, onset of symptoms referable to cyst
DIAGNOSTIC CHECKLIST
• AC centered in midline; cyst center over neural foramen
implies Tarlov cyst
112
(Left) Sagittal T2WI MR
demonstrates a small
extradural sacral arachnoid
cyst ſt at the caudal end of
the spinal canal. The conus
termination is normal.
Note that the cyst signal
intensity is slightly brighter
than CSF within the dural sac,
reflecting increased
proteinaceous content. (Right)
Axial T2WI MR through the
sacrum at the level of the
arachnoid cyst ſt confirms
mild expansile remodeling of
the caudal osseous spinal
canal by the cyst at the sacral
level.
Sacrococcygeal Teratoma
KEY FACTS
Congenital and Genetic Disorders
TERMINOLOGY
• Congenital sacral tumor containing elements of all 3 germ
layers
IMAGING
• Large, heterogeneous sacral mass in infant
○ Variably contains calcifications, mixed solid and cystic
components, fat-debris levels, bone, hair, teeth, or
cartilage
• Usually large at diagnosis
TOP DIFFERENTIAL DIAGNOSES
• Anterior sacral meningocele
• Chordoma
• Dermoid tumor
• Exophytic rhabdomyosarcoma
PATHOLOGY
• Tumor originates from totipotential cell rests at caudal
spine/notochord (Hensen node)
• Altman/AAP classification: 4 surgical subtypes
○ Type I: Primarily external (47%) → best prognosis
○ Type II: Dumbbell shape, equal external/internal portions
(34%)
○ Type III: Primarily internal within abdomen/pelvis (9%)
○ Type IV: Entirely internal (10%) → worst prognosis
CLINICAL ISSUES
• Back/pelvic mass in newborn
○ Exophytic masses (AAP types I, II) easily diagnosed, but
internal (types III, IV) occult → delayed diagnosis
• In utero presentation
○ Polyhydramnios, high-output cardiac failure with
hydrops, hepatomegaly, placentomegaly
DIAGNOSTIC CHECKLIST
• Heterogeneous sacral tumor ± calcification, cysts,
hemorrhage in infant strongly suggest diagnosis
• AAP type influences prognosis and treatment approach
(Left) Sagittal graphic (AAP II)
depicts a typical large,
heterogeneous, partially cystic
sacrococcygeal teratoma
located anterior to the sacrum
with both internal and
external components. (Right)
Sagittal T1WI MR (AAP type I)
demonstrates a predominately
cystic sacrococcygeal
teratoma ſt contiguous with
the coccyx tip. The tumor is
nearly entirely external. The
urinary bladder is not
displaced. Hyperintense rectal
contents st probably reflect
meconium.
(Left) Sagittal T2WI MR (AAP
type II) reveals a large,
heterogeneous exophytic
sacral mass with relatively
equal internal and external
distribution. The mass
displaces the urinary bladder
ſt anteriorly and superiorly.
(Right) Sagittal STIR MR (AAP
type III, older female infant)
reveals a heterogeneous,
predominantly internal pelvic
mass ſt. The tumor anteriorly
and upwardly displaces the
rectum st and urinary bladder
. No sacral osseous
destruction is apparent.
113
Klippel-Feil Spectrum
KEY FACTS
TERMINOLOGY
• Synonyms: Klippel-Feil syndrome (KFS)
• Congenital spinal malformation characterized by
segmentation failure of ≥ 2 cervical vertebrae ± thoracic,
lumbar segmentation failure
IMAGING
• Single- or multiple-level congenital cervical segmentation
and fusion anomalies
• C2-3 (50%) > C5-6 (33%) > CVJ, upper thoracic spine
• Vertebral bodies usually smaller than normal
Congenital and Genetic Disorders
• Vertebral body narrowing ("wasp waist") at fused
rudimentary disc space ± fusion of posterior elements
TOP DIFFERENTIAL DIAGNOSES
• Juvenile idiopathic arthritis
• Surgical fusion
• Chronic sequelae of discitis
• Ankylosing spondylitis
(Left) Sagittal CT of the
cervicothoracic spine shows
lack of segmentation of the
cervical and thoracic spinal
column. Note C1 spinous
process fused to the occiput
and fusion of bodies and
posterior elements ſt of C6T4. Note accelerated disc
degeneration at C5-C6 st.
(Right) Lateral radiograph
[Klippel-Feil spectrum type 2
(KFS 2)] demonstrates typical
C2/3 congenital segmentation
failure ("fusion") with
characteristic rudimentary disc
space ſt and fusion of the
facets and spinous processes.
PATHOLOGY
• Sporadic; familial genetic component with variable
expression identified in many patients
• Type 1 (9%): Massive fusion of cervical, upper thoracic spine
→ severe neurological impairment, other abnormalities
• Type 2 (84%): Fusion of ≥ 1 cervical vertebral interspace
• Type 3 (7%): Fusions involve cervical and lower
thoracic/lumbar vertebra
CLINICAL ISSUES
• Classic triad (33-50%): Short neck, low posterior hairline,
and limited cervical motion
• Wide variation in clinical and anatomical expression
DIAGNOSTIC CHECKLIST
• Much KFS morbidity and nearly all mortality related to
visceral system dysfunction
• Look for instability, progressive degenerative changes,
cord/brainstem compression
114
(Left) Sagittal bone CT (KFS 1)
reveals extensive fusion of all
cervical vertebrae and
posterior elements, with the
characteristic hypoplastic
appearance of the vertebrae
and intervertebral disc spaces.
In this patient, there is
additionally incorporation of
C1 into the skull base
("occipitalization of the
atlas"). (Right) Axial bone CT
(KFS 1, severe segmentation
anomalies) demonstrates the
vertebral articulation of a
unilateral left omovertebral
bone .
Failure of Vertebral Formation
KEY FACTS
Congenital and Genetic Disorders
TERMINOLOGY
• Vertebral dysplasia, segmentation and fusion anomaly,
"disorganized spine"
• Partial or complete failure of vertebral formation
IMAGING
• Sharply angulated, single curve, or focal (kypho)scoliosis
• Hemivertebra, butterfly vertebra generally smaller than
normal vertebra
TOP DIFFERENTIAL DIAGNOSES
• Vertebral fracture, history critical
• Inherited spinal dysplasias
PATHOLOGY
• Deranged PAX1 gene expression in developing vertebral
column
• Many syndromes manifest vertebral dysplasia
• Associated anomalies include dysraphism, split notochord
syndromes, visceral anomalies (61% of congenital scoliosis
patients)
CLINICAL ISSUES
• Many asymptomatic or detected during scoliosis evaluation
• Syndromal patients usually detected in infancy
○ Abnormal spine curvature ± neural deficits, limb or
visceral abnormalities
○ Respiratory failure (impeded chest movement 2° to
fused ribs, kyphoscoliosis)
DIAGNOSTIC CHECKLIST
• Important to look for and characterize associated visceral
anomalies
• Type of deformity determines propensity for scoliosis
progression
(Left) Coronal graphic of the
thoracolumbar spine
demonstrates several different
types of vertebral formation
failure, with segmented
"balanced" L1 and L4
hemivertebrae ſt and a T11
butterfly vertebra . (Right)
Anteroposterior radiograph
shows segmented right T7 and
left T11 hemivertebrae ſt
producing focal scoliotic
curves. Because they mostly
cancel each other's curve, this
configuration is considered
"balanced" for the purposes of
prognostic and treatment
planning.
(Left) Coronal T2WI MR
demonstrates left T6 and right
T8 hemivertebrae ſt. There is
only minimal resultant
leftward curvature because
the 2 hemivertebrae "balance"
each other, and this curvature
would not be expected to be
rapidly progressive. (Right)
Axial T2WI MR depicts the
abnormal intervertebral disc
space appearance in the
presence of a hemivertebra.
Diagnosing hemivertebra is
most straightforward in the
coronal plane and often
difficult in the sagittal and
axial planes.
115
Vertebral Segmentation Failure
KEY FACTS
TERMINOLOGY
• Synonyms: Segmentation anomaly, segmentation and
fusion anomaly, "block vertebra"
IMAGING
• Sharply angulated focal scoliotic curvature with abnormal
"fused" vertebra
○ Ranges single level → extensive multilevel involvement
○ Lumbar > cervical > thoracic
• May have scoliosis, kyphosis, cord compression
• Search for related fused pedicles, ribs, posterior elements
Congenital and Genetic Disorders
TOP DIFFERENTIAL DIAGNOSES
• Juvenile chronic arthritis
• Surgical vertebral fusion
• Chronic sequelae of discitis
• Ankylosing spondylitis
(Left) Coronal graphic of the
thoracolumbar spine
demonstrates multilevel
failure of vertebral
segmentation producing
congenital scoliosis. Space
between the dysplastic
vertebra is filled with cartilage
and aberrant disc material.
(Right) Coronal bone CT
(congenital scoliosis) shows
multiple examples of vertebral
segmentation failure with
several right-sided
hemivertebra ſt that have
failed to successfully segment,
producing a jumble of
malformed vertebra and
multiple curve scoliosis.
PATHOLOGY
• Deranged PAX1 gene expression → abnormal notochord
signaling in developing vertebral column
• Many syndromes associated with segmentation fusion
anomalies
• Associations include other neuraxis anomalies, renal,
gastrointestinal, congenital cardiac defects
CLINICAL ISSUES
• Usually asymptomatic or present with kyphoscoliosis
• Less commonly neural deficit, limb or visceral anomalies,
respiratory failure
• Scoliosis frequently progressive
DIAGNOSTIC CHECKLIST
• Clinical manifestations variable, determined by type of
segmentation anomaly and syndromal association
• Block vertebra usually larger than single normal vertebral
body
116
(Left) Coronal 3D bone CT
reformat shows multiple curve
scoliosis with convex right
thoracic and convex left
thoracolumbar kyphoscoliosis
resulting from multiple levels
of vertebral segmentation
failure. 3D CT is best for fully
characterizing contribution of
the various anomalous
vertebra to scoliosis and
kyphosis for treatment
planning. (Right) Sagittal 3D
CT reformat demonstrates
focal kyphosis at the
thoracolumbar junction
related to multilevel vertebral
segmentation failure.
Diastematomyelia
KEY FACTS
Congenital and Genetic Disorders
TERMINOLOGY
• Synonyms: Split cord malformation (SCM), "diastem"
IMAGING
• Sagittal division of spinal cord into 2 hemicords, each with 1
central canal, dorsal horn, and ventral horn
○ Hemicords usually reunite above and below cleft
○ ± fibrous or osseous spur
• Frequently associated vertebral segmentation anomalies
• Imaging evaluation
○ Consider ultrasound to screen infants with skin dimple or
cutaneous marker
○ MR most definitive for characterization
○ Supplement with bone CT ± myelography to optimally
define spur anatomy for surgical planning
TOP DIFFERENTIAL DIAGNOSES
• Duplicated spinal cord (diplomyelia)
PATHOLOGY
• "Split notochord syndrome" is spectrum of
diastematomyelia, dorsal enteric fistula/sinus, and dorsal
enteric cysts/diverticula
• Spinal cord split into symmetric or asymmetric hemicords
• Either 1 (type II) or 2 (type I) dural tubes
CLINICAL ISSUES
• May be clinically indistinguishable from other causes of
tethered spinal cord in absence of cutaneous stigmata
○ Cutaneous stigmata indicate diastematomyelia level (>
50%); "fawn's tail" hair patch most common
DIAGNOSTIC CHECKLIST
• Search for diastematomyelia in patients with cutaneous
stigmata, intersegmental fusion of posterior elements,
clinical tethered cord
• Presence of spur = type I SCM; more severe symptoms and
anomalies, worse prognosis
(Left) Coronal T1WI MR [type I
split cord malformation (SCM)]
shows multiple vertebral
segmentation anomalies, with
large midline osseous spur ſt
that splits the thoracic spinal
cord into 2 hemicords. Note
associated multiple posterior
element and rib fusions.
(Right) Sagittal T1WI MR (type
I SCM) shows a large osseous
spur ſt extending from the L2
vertebral body to the
dysplastic posterior elements.
The spinal cord is low lying
and tethered by a lipoma
and extradural arachnoid cyst
. Note solitary pelvic kidney
st anterior to the sacrum.
(Left) Axial T2WI MR confirms
characteristic "splitting" of the
abnormal spinal cord into 2
symmetric hemicords . The
prominent osseous spur ſt
classifies this patient as a type
I SCM. (Right) Axial bone CT
following myelography (type I
SCM) shows dural tube
division by an osseous septum
ſt. Two hemicords are
produced. The left spinal
lamina st is dysraphic.
117
Neurenteric Cyst
KEY FACTS
TERMINOLOGY
• Synonyms: Spinal enterogenous cyst, spinal enteric cyst,
spinal dorsal enteric cyst
IMAGING
• Intraspinal cyst ± vertebral abnormalities (persistent canal
of Kovalevsky, vertebral anomalies)
• Thoracic (42%) > cervical (32%) > > lumbar spine,
intracranial/basilar cisterns (rare)
TOP DIFFERENTIAL DIAGNOSES
• Arachnoid cyst
Congenital and Genetic Disorders
• (Epi)dermoid cyst
• Anterior thoracic meningocele
PATHOLOGY
• Subgroup of split notochord syndrome spectrum
○ Sporadic or syndromic (Klippel-Feil, VACTERL, OEIS
syndromes)
(Left) Sagittal T1WI MR
demonstrates a large ventral
extradural cystic mass ſt
(neurenteric cyst) producing
spinal cord compression. CVJ
segmentation anomalies are
better demonstrated on other
slices (not shown). (Courtesy
M. Brandt-Zawadzki, MD.)
(Right) Axial T2WI MR
confirms a ventral, extradural
neurenteric cyst ſt that
displaces the spinal cord and
dura to the left, resulting in
mild spinal cord compression
. (Courtesy M. BrandtZawadzki, MD.)
○ Association with vertebral anomalies, diastematomyelia,
lipoma, dermal sinus tract, and tethered spinal cord
CLINICAL ISSUES
• Most common symptoms: Back/radicular pain,
paraparesis/paresthesias, gait disturbance, meningitis
○ Children usually present with cutaneous stigmata, spinal
dysraphism symptoms
○ Adults present primarily with pain, myelopathy
• Some asymptomatic, but most show progressive
neurological deterioration
• Primary treatment goal is complete surgical excision
○ Drainage, partial resection if complete excision not
possible
DIAGNOSTIC CHECKLIST
• Imaging appearance reflects cyst composition
• Look for associated mediastinal or abdominal cysts,
connecting fistulae, or vertebral anomalies
118
(Left) Sagittal bone CT
(Klippel-Feil syndrome) after
myelography shows a sagittal
vertebral cleft in
conjunction with a ventral
extradural neurenteric cyst
ſt. The cyst produces mild
spinal cord displacement.
(Right) Sagittal T1WI MR
demonstrates a large,
dumbbell-shaped neurenteric
cyst ſt extending from the
mediastinum into the central
canal through a patent canal
of Kovalevsky , producing
marked spinal cord
compression. (Courtesy S.
Blaser, MD.)
Os Odontoideum
KEY FACTS
Congenital and Genetic Disorders
TERMINOLOGY
• Corticated oval or round ossicle (os) at odontoid process tip
IMAGING
• Well-defined round or oval ossicle at dens tip with smooth,
uniform cortex
• ± hypertrophy of anterior C1 (atlas) arch
• ± spinal cord contusion, myelomalacia (if craniocervical
instability)
TOP DIFFERENTIAL DIAGNOSES
• Ossiculum terminale
• Odontoid C2 fracture (type II)
PATHOLOGY
• 2 types based on os position
○ Orthotopic: Os in anatomic position
○ Dystopic: Os in any position other than orthotopic
(considered less stable)
• Incompetence of transverse atlantal ligament → C1/2
instability
CLINICAL ISSUES
• Commonly asymptomatic
○ Os incidentally detected on imaging obtained for other
reasons (e.g., trauma)
○ Nonoperative management recommended for most
patients incidentally diagnosed with os odontoideum
• Symptomatic patients
○ Local mechanical neck pain, torticollis, headache, or
other neurological symptoms
○ Surgical stabilization for spinal instability, neurologic
decline, or intractable pain
• Prognosis variable; depends in large part on CVJ
ligamentous stability
DIAGNOSTIC CHECKLIST
• Evaluate dynamic CVJ stability when os odontoideum is
identified
(Left) Sagittal graphic of the
cervical spine demonstrates an
orthotopic os odontoideum
ſt. There is mild separation of
the os away from the odontoid
process toward the clivus
st. Note the maintenance of
normal os distance to the
mildly enlarged anterior C1
ring . (Right) Sagittal T2WI
MR of the craniovertebral
junction depicts an orthotopic
os odontoideum ſt with close
os approximation to the
anterior C1 arch . The
cervical spinal cord is normal.
(Left) Sagittal bone CT reveals
enlargement of the C1
anterior ring in conjunction
with mildly dystopic os
odontoideum ſt that is
discontiguous with the
dysplastic, rounded odontoid
process st. Note maintenance
of os alignment with C1 and
the clivus. (Right) Coronal
bone CT confirms discontinuity
of the rounded os
odontoideum ſt with the C2
vertebral body. The os is mildly
displaced to the left.
Alignment of the occipital
condyles and C1 lateral
masses is normal.
119