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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4504_Библиотеки_им_академика_М_И_Перельмана
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J. E. Vandevenne and A. Kastler
tumor, often not seen by the clinician but it should be reported
and clearly communicated by the radiologist. An MRI of the
cervical spine may reveal the pancoast tumor, but only if the
radiologist specically looks at the outer most lateral sagittal
T1-weighted images of the C-spine where the lung apices are
visualized. Even the localizer images of CT or MRI may
demonstrate the presence of a malignant tumor outside the
spine (Figs.20.1 and 20.2).
When reading plain radiography of the thorax, one should
specically look at the spinal elements including the paraspinal lines and soft tissue, both on the lateral and the frontal
Fig. 20.1 (a, b) Detection of
a clinically signicant mass.
Tunnel vision into the spinal
canal by physicians may
obviate the timely diagnosis
of a renal cell carcinoma (a).
Not looking at the scout
images of an MRI of the spine
may obviate the timely
diagnosis of a lung
adenocarcinoma (b)
view. It may reveal a paraspinal mass only visible by displaced paraspinal lines (Fig.20.3).
Key Point Objectives
• Extraspinal masses may change the clinical pathway for your patient, but only if the radiologist
picks up the extraspinal lesion (cave satisfaction of
search).
Fig. 20.2 (a, b) Detection of
a clinically signicant mass.
Failure to evaluate upper and
lower corners of the images
may result in missed
diagnosis of a vertebral artery
aneurysm (a). Failure to
evaluate the outer most lateral
sagittal T1-weighted image of
the C-spine may result in
missed diagnosis of a
pancoast tumor (b)
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Fig. 20.3 (a, b) Detection of
a paraspinal mass on
radiography. Actively looking
for abnormal paraspinal lines
when reading non-spinal
radiographies may improve
detection of paraspinal
masses, such as a tuberculosis
abscess
a b
20.2 Anatomical Compartments
inandAround theSpine: Paraspinal,
Vertebral, andEpidural
The paraspinal compartment extends from the parietal fascia
ventrally to the paraspinal muscle aponeurosis dorsally and
from the skull base to the coccyx. It consists of soft tissues
and surrounds the vertebrae and proximal part of the ribs [5].
The main soft tissue structure of the paraspinal compartment is muscle. Supercial muscles such as trapezius, latissimus dorsi, and levator scapulae do not belong to the
paraspinal compartment because these are located supercial
to the paraspinal aponeurosis. Deep to the paraspinal aponeurosis and thoracolumbar fascia (posterior layer) are the
muscles of the epiaxial paraspinal compartment such as erector spinae and multidi. Anterior to the transverse processes,
muscles such as psoas and quadratus lumborum in the lumbar spine and longus colli in the cervical spine are present in
the hypaxial paraspinal compartment. At the thoracic spine,
no muscle is present anterior to the transverse processes and
disease may more easily spread anteriorly to the parietal fascia (pleura). Open connection exists between the paraspinal
soft tissues anterior (hypaxial) and posterior (epiaxial) to the
transverse processes at all spinal levels. At the lumbar level,
the middle layer of the thoracolumbar fascia forms an intermuscular septum at the level of each transverse process but
in between the processes a narrow communication persists.
This explains the often dumbbell shape of soft tissue tumors
extending in the muscles anterior and posterior to the transverse process.
The paraspinal compartment is not well enclosed as it
communicates with the epidural space of the spinal canal and
the intercostal spaces; anteriorly, it is intimately related to
the posterior mediastinum, pleura, and retroperitoneum.
Moreover, the extensive vascular network and neural structures together with fat planes make passageways for infec-
tious and tumoral lesions to extend into or outside the
paraspinal compartment. As such, spread of disease may easily occur by locoregional contiguity and by hematogeneous
or perineural dissemination. Thorough radiological description of the tumoral spread and relation to neural and vascular
structures is key information for surgeons.
The vertebral compartment contains the vertebrae and
discs. Primary or secondary vertebral tumors may readily
extend through the relative thin cortical bone and the periost
into the epidural space or the paraspinal soft tissue. The
Batson plexus consisting of the internal venous vertebral
plexus, the basivertebral veins, and the external venous vertebral plexus connects intravertebral lesions to the paraspinal
soft tissues (or vice versa), and to segmental veins towards
the azygos and caval veins permitting hematogeneous spread.
The spinal epidural space lies outside the dura mater and
within the spinal canal, and it extends from the foramen
magnum to the sacrum. It contains epidural fat, spinal nerves,
epidural veins and arteries, and meningovertebral ligaments.
This space is connected to the vertebral body via the basivertebral veins and extends to the paraspinal compartment via
the intervertebral foramina.
From the above paragraphs, it may be evident that extracompartmental extension frequently occurs in particular for
tumors with aggressive behavior or malignant nature. The
radiologist who is knowledgeable of the routes of spread will
be able to guide the clinician and surgeon in their management decisions. The paraspinal compartment contains the
adipose tissue corridor between the paraspinal muscles and
along paraspinal vessels and nerves. It connects to the epidural space and the intercostal spaces. Contralateral spread
may take place via the epidural space, throughout the bone or
via the soft tissues anteriorly to the vertebrae (Fig. 20.4).
Craniocaudal extension may easily occur within the epidural
space and via the longitudinally oriented muscles and fat
planes of the paraspinal compartment.
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J. E. Vandevenne and A. Kastler
Fig. 20.4 Anatomy of the paraspinal space on axial T1WI (a, b).The
green line surrounds the epiaxial paraspinal space and the green dashed
line the hypaxial paraspinal space. Red arrows show the possible path-
ways involved in paraspinal tumor spread along fat planes (shown in
yellow). Note: epiaxial lesions are located posterior to and hypaxial
lesions anterior to the transverse process. (From [5], licensed under
CC-BY 4.0)
neurovascular involvement. T1-weighted sequences and
Key Point Objectives
• Anatomical compartments in and around the spine
T2-weighted sequences with fat saturation both in sagittal
and axial planes are preferred.
are not well compartmentalized and lesions can easily spread between vertebral body, epidural space,
and paraspinal space.
20.3.1 Weinstein-Boriani-Biagini Classication
After describing the compartments involved and the craniocaudal segments involved, the radiologist can use the
20.3 Grading ofMasses inandAround
theSpine
Weinstein-Boriani-Biagini classication regarding tumor
extension in the axial plane to help the surgeon in treatment
planning (Fig. 20.5). This classication divides spinal and
Once a mass is detected by imaging, grading of the mass is
necessary. Grading includes looking for features that show
the aggressiveness of the tumor and dening the compartments involved. Grading can be helpful for characterization
of a mass, and grading is of high importance to direct clinical
and surgical management.
Radiography may provide insight into the overall mor-
paraspinal regions into ve concentric layers regarding depth
of tumor involvement (from paraspinal soft tissue, supercial bone, deep bone, epidural, to intradural involvement)
while location is determined using a clockwise 12-sector
grid. Surgical resection strategies may involve complete vertebral corporectomy, sagittal hemicorporectomy, or posterior
arch resection.
phology of the spine, is the best modality to evaluate spinal
alignment in standing position (as required for the SINS
classication, see below), and shows if the lesion will be visible on intra-operative radiography.
20.3.2 Spinal Instability Neoplastic Score
(SINS)
CT demonstrates the matrix of the tumoral mass (osteoid,
chondroid, dystrophic) and the bony changes such as lytic,
mixed and osteoblastic, expansile or exostosis, scalloping or
foraminal enlargement, and periosteal reaction. Slowgrowing lytic lesions are often surrounded with a thin sclerotic margin while fast-growing aggressive lesions have a
wide transitional zone with ill-dened bone destruction, and
moth-eaten cortical permeation.
MRI is the modality of choice to dene size and extent of
the tumoral mass. Bone involvement, spinal canal, and soft
tissue involvement are well visualized due to excellent contrast resolution. It allows for tumor staging and detection of
Vertebral lesions may lead to instability of the spine.
Radiography, CT and MRI can be used to evaluate stability
and fracture risk. The Spine Instability Neoplastic Score
(SINS) assesses six variables: location of lesion, type of
pain, type of bony lesion, radiographic spinal alignment,
degree of vertebral body collapse, and involvement of posterolateral spinal elements (Table20.1). The scores for each
variable are added resulting in a nal score between 0 and
18. A score of 0–6 denotes stability, a score of 7–12 denotes
indeterminate (possibly impending) instability, and a score
of 13 to 18 denotes instability [7].
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a
b
c
d
e
Fig. 20.5 Weinstein-Boriani-Biagni (WBB) classication: a surgical
staging system that divides the vertebra into 12 equal radiating zones in
an axial plane (1–12) and into ve concentric layers regarding depth of
tumor involvement (a–f); it is used to establish feasibility criteria and
Table 20.1
unstable)
Spinal instability neoplastic score (SINS) component Score (0–18)
Location
Junctional (occiput-C2, C7–Th2, Th11–L1, L5–S1) 3
Mobile spine (C3–C6, L2–L4) 2
Semi rigid (Th3–Th10) 1
Rigid (S2–S5) 0
Pain
Mechanical pain
Occasional pain but not mechanical 1
Pain-free lesion 0
Bone lesion
Lytic 2
Mixed (lytic/blastic) 1
Blastic 0
Radiographic spinal alignment
Subluxation/translation present 4
De novo deformity (kyphosis/scoliosis) 2
Normal alignment 0
Vertebral body collapse
>50% collapse 3
<50% collapse 2
No collapse with >50% of body involved 1
None of the above 0
Posterolateral involvement of spinal elements
Bilateral 3
Unilateral 1
None of the above 0
a
Pain improvement with recumbency and/or pain with movement/load-
ing of spine
b
Facet, pedicle, or costovertebral joint fracture or replacement with
tumor
Spinal Instability Neoplastic Score (0–6: stable; 13–18:
a
b
3
strategy for tumor resection [6]. (a) Extraosseous soft tissue; (b)
Intraosseous (supercial); (c) Intraosseous (deep); (d) Extraosseous (epidural); (e) Extraosseous (intradural); (f) Vertebral artery involvement (not
shown). (Medical art licensed under CC-BY 4.0 by Annick Gryspeirt)
20.3.3 Epidural Spinal Cord Compression
(ESCC) Scale, Bilsky Score
Vertebral body metastatic disease may extend in the epidural
space and may compress the spinal cord in particular after
vertebral body collapse. The Epidural Spinal Cord
Compression (ESCC) score, also known as the Bilsky score
and based on MRI only, helps to determine the management
strategy regarding radiotherapy and surgery [8]. Grade 0
(bone only disease), grade 1a and 1b (epidural extension
without or with deformation of the thecal sac) can be treated
with radiotherapy. Treatment strategy for grade 1c (deformation of the tecal sac with spinal cord abutment) remains controversial. Grade 2 and 3 (spinal cord compression with and
without visible cerebrospinal uid around the cord) require
surgical decompression except for highly radiosensitive
tumors (Fig. 20.6). For other neoplasms involving the
epidural space, grade 1–3 can be used to express the degree
of spinal cord compression.
Key Point Objectives
• Radiologists add value to patient management decisions by grading the tumors according to established scales and scores.
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01
1b
Fig. 20.6 Epidural spinal cord compression (ESCC) scale (Bilsky
score) used to describe metastatic tumor extension from the vertebral
body into the spinal canal and to assess the degree of spinal cord compromise. Low grade includes bone only disease (grade 0), epidural
impingement without deformation of thecal sac (grade 1a), deformation
of the thecal sac without spinal cord abutment (grade 1b), and deformation of the thecal sac with spinal cord abutment (grade 1c); high grade
includes spinal cord compression with cerebrospinal uid visible somewhere around the cord (grade 2) and spinal cord compression without
cerebrospinal uid visible (grade 3). Orange color represents tumor
extending from vertebral body, yellow color represents the epidural
space, and blue color represents the cerebrospinal uid in the thecal sac
(medical art licensed under CC-BY 4.0 by Annick Gryspeirt)
b
20.4 Characterization ofMasses
inandAround theSpine
20.4.1 Mass intheParaspinal Space
To characterize the detected mass, clinical information
should be considered together with the imaging ndings [5,
9–11]. Clinical info should mention age and medical data
including oncologic history, neurobromatosis, chronic anemia such as in sickle cell disease or thalassemia, immunosuppression (lymphoma), trauma, infectious lab ndings or
endemic areas for infections such as tuberculosis, brucellosis, echinococcosis, and cysticercosis.
Image analysis starts with locating the epicenter of a
mass: within the bone, in the epidural space, in the paraspinal compartment anterior or posterior to the transverse process (hypaxial or epiaxial, respectively). Extramedullary
hematopoiesis and nerve sheath tumors will almost invariably present anterior to the transverse processes. Lipomas
and liposarcomas may arise anterior or posterior to the transverse process. Posterior to the transverse process, benign
tumors such as bromatosis, hemangioma, epidermoid cyst,
and hibernoma are found together with malignant sarcomas
such as synovial sarcoma, malignant peripheral nerve sheath
tumor (MPNST), synovial sarcoma, leiomyosarcoma, and
undifferentiated sarcoma.
Tumors located at the aponeurosis of the paraspinal muscles include desmoid and nodular fasciitis. At the boundaries
of the paraspinal region, invading tumors from the skin
appendages or tumors arising from anteriorly through the
parietal fascia in the thorax and abdomen should be considered. Lipomas and pseudotumors such as hematoma and
abscesses may occur at any site. Tables, owcharts, and case
examples are shown in the following sections (Figs.20.7,
20.8, 20.9, and 20.10).
20.4.2 Mass Within theVertebra
Diagnosis of vertebral masses may be quite challenging and
several classications can be used to distinguish vertebral
tumors such as neoplastic vs. non-neoplastic, malignant vs.
benign tumor, primitive vs. secondary, and the origin of a
tumor, hematopoietic vs. osteogenic vs. chondrogenic vs.
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Fig. 20.7 As well known from soft tissue tumor MR imaging, masses
containing fat, methemoglobin, protein-rich uid or melanin will show
high T1 signal intensity; hypercellular or myxoid lesions demonstrate
uid intensities; brous tumors with predominant collagen present with
low signal intensity both on T1- and T2-weighted images; uid-uid
levels can be a sign of blood-lled cavities. Post-contrast T1-weighted
images help to separate solid fromSpinal massesparaspinal space cystic
lesions, to estimate vascularity of the mass and identify tumor necrosis.
Fig. 20.8 (a–d) GLI1 fusion
soft tissue sarcoma in a
middle-aged woman, located
in the hypaxial paraspinal
space in the upper thoracic
spine and extending through
the intervertebral foramen
(Bilsky grade 1C). Because of
the widened intervertebral
foramen, the initially small
mass was in follow-up as a
benign peripheral nerve
sheath tumor (a). Progressive
growth, bone involvement
(vertebral body and facet),
necrotic and solid components
lead to suspicion of
malignancy and subsequent
surgery (b–d)
c
(a, b) Lipoma or low-grade liposarcoma in the epiaxial paraspinal
space, involving and enlarging the intermuscular fat planes and
extending into the intervertebral foramen with some compression of the
thecal sac, i.e., Bilsky grade 1b (a). The lesion is almost homogeneously
hyperintense on T1WI inferring the diagnosis of lipoma, but because of
its size (see longitudinal extension) low-grade liposarcoma should be
suspected (b)
d
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Fig. 20.9 Flowchart for paraspinal masses. Stars represent soft tissue
tumors with bone involvement. BPMNST, benign peripheral nerve
sheath tumor; MPNST, malignant peripheral nerve sheath tumor; ABC,
aneurysmal bone cyst; CS, chondrosarcoma; GCT, giant cell tumor;
PCT, plasma cell tumor; US, undifferentiated sarcoma; and SS, synovial sarcoma. (From [5], licensed under CC-BY 4.0)
Fig. 20.10 Overview of paraspinal masses. Stars represent the more
common lesions. Words in bold represent benign lesions. BPMNST,
benign peripheral nerve sheath tumor; MPNST, malignant peripheral
nerve sheath tumor; ABC, aneurysmal bone cyst; CS, chondrosarcoma;
GCT, giant cell tumor; PCT, plasma cell tumor. (From [5], licensed
under CC-BY 4.0)
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Fig. 20.11 (a–c) Metastasis. Aggressive bone lesion with involvement
of vertebral body and lamina, cortical permeation, and extension in the
spinal canal. Intermediate to high signal on T2WI and homogeneous
low signal on T1WI with avid enhancement are seen (a–c). At the pos-
vascular origin, etc. Therefore, nal diagnosis must be made
after assessment of both available imaging data (MRI and
CT) and setting (age, sex, location, and clinical presentation)
in order to accurately diagnose a vertebral mass. Typical presentation of specic lesions may result in “do-not-touch”
lesions, meaning that a biopsy is not necessary; in unresolved
cases, a biopsy may be deemed necessary for diagnosis.
20.4.2.1 Vertebral Metastasis
Arguments in favor of metastatic spine disease usually
include multi-level lesions and presence of primary tumor
known to be associated with bone metastasis (lung, breast,
prostate, kidney, thyroid are the most common). Diagnosis of
metastatic disease may be challenging in the case of a solitary
mass with no known cancer setting, often requiring biopsy.
Imaging features of metastatic disease include highly lytic
lesions, highly sclerotic lesions, or mixed presentations.
Osteolytic lesions are hyperintense on T2WI, iso- to hypointense on T1 with strong enhancement after IV contrast
(Fig.20.11), which correlates on CT with hypodense lesions
that have indistinct borders often with permeation of cortical
bone as in the Lodwick classication [12]. Local extension to
surrounding soft tissues should be looked for, and the classic
“draped curtain” presentation in the epidural space may be
present. Metastatic disease may also present as a highly sclerotic bone lesion (hyperdense on CT, low signal on T1WI and
T2WI) in primary tumors such as prostate, breast, transitional
cell, and medullary thyroid carcinomas, lung adenocarcinoma, carcinoid, lymphoma (ivory vertebra), and small cell
lung cancer. Bone metastases may have a mixed presentation
of both lytic and sclerotic areas (e.g., 25% of breast carcinoma, 15% of prostate carcinoma, 15% of lung carcinoma,
testicular tumors, cervix carcinoma, gastrointestinal cancer).
Metastases may affect all bony segments of the vertebra.
c
terior border of the vertebral body, the posterior longitudinal ligament
is lifted by the metastasis, known as “draped curtain” sign. (b, c) The
epidural space involvement has resulted in spinal cord compression
(Bilsky grade3)
20.4.2.2 Primary Malignant Tumors
oftheVertebrae
These tumors are rare and present mainly in patients over
30 years of age and mainly involve the vertebral body.
However, osteosarcoma, chondrosarcoma, and Ewing sarcoma are often seen in younger ages and have a propensity
to occur in the posterior elements of vertebra before
extending towards the vertebral body. Longitudinal extension to adjacent vertebral levels is most often seen in lymphoma followed by chordoma and chondrosarcoma
[13–15].
Epidemiology, preferred location, and involvement of
adjacent vertebra together with some imaging examples are
shown (Table 20.2, Figs. 20.11, 20.12, 20.13, 20.14, and
20.15).
20.4.2.3 Primary Benign Tumors
oftheVertebrae
These tumors may be classied according to tissue of origin
such as osteogenic, chondrogenic, vascular, osteoclastic
giant-cell rich, notochordal, mesenchymal, or hematopoetic
[16, 17]. Characteristic imaging features often allow a specic diagnosis based on imaging and will avoid the need for
biopsy (Table 20.3). Some imaging examples are shown
(Figs.20.16, 20.17, and 20.18).
20.4.3 Mass intheEpidural Space
Epidural masses are relatively limited in origin as they can
either be derived from vascular or fat tissue. However, many
tumoral or pseudotumoral lesions may invade or compromise the epidural space (Table20.4). Some imaging examples are shown (Figs.20.19, 20.20, and 20.21).
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Table 20.2 Epidemiology, preferred location, and extension of primary malignant tumors of the vertebrae
Axial location and
Tumor type
Ewing sarcoma 19.3 S>L>T>C Posterior elements
Osteosarcoma 38 T+L>S, C Posterior elements
Chondrosarcoma 45 T>C>L All + adjacent levels
Lymphoma 40–60 All Body + adjacent
Chordoma 50–60 Skull base, S (C,
Plasmacytoma >60 T Body (extension in
Multiple
myeloma
C cervical, T thoracic, L lumbar, S sacral
Mean
age (y) Spine location
T, L)
Rare
under
30
All Body (extension in
longitudinal
extension
(extension in body)
levels
Body + adjacent
levels
pedicle and in disk)
pedicle and in disk)
J. E. Vandevenne and A. Kastler
Fig. 20.12 (a–d) Chordoma
of the sacrum. On MRI, the
lesion is iso- to hyperintense
on T2WI (a), iso- to
hypointense on T1WI (b, c).
It demonstrates avid
inhomogeneous enhancement
referred to as “honeycomblike” in T1WI with fat
saturation (d). It demonstrates
features of an aggressive
tumor, with cortical
disruption, soft tissue
invasion, and longitudinal
extension. Diagnosis usually
requires biopsy
a b
c
d
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Fig. 20.13 (a–c) Diffuse large B-cell lymphoma of the thoracic spine in
an elderly patient presenting with chronic dorsal pain and claudication. CT
demonstrates an ivory vertebra together with paraspinal soft tissue mass
(a). MRI shows the soft tissue extension in the hypaxial paraspinal space
towards the posterior mediastinum, in the intercostal spaces, and in the
epidural space with compression of the spinal cord, i.e., Bilsky grade 3 (b,
c). Longitudinal extension in both the paravertebral space and the intradural space is seen together with vertebral involvement over at least 6 levels
c
ab
c
Fig. 20.14 (a–c) Multiple myeloma. When reading spine MRI exams,
the astute radiologist will report the possibility of multiple myeloma in
case of an elderly patient with multiple consecutive vertebral compression
fractures, diffusely heterogeneous bone marrow, and in particular “red
bone marrow” nodules in the normally fatty sacral wings of the elderly (c).
Note: always look at the sacral wings in the outer most sagittal T1 images
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