BENIGN
Giant Cell Tumor: Fig. 1 Fig. 2 Fig. 3 Fig. 4
- Only 3–7% of all giant cell tumors occur in spine; most of them in the sacrum.
- Second most common primary tumor of the sacrum.
- Women predominance (2:1).
- Ages between 15 and 40 years.
- Pain and neurologic deficits are the most common symptoms.
- Composed of osteoclastic giant cells.
Locally aggressive.
Matrix calcifications and septations are absent.
Hemorrhagic and fibrotic areas are commonly found.
Spontaneous malignant transformation has been reported in fewer than 2% of patients,
but it often occurs after radiation therapy.
- On CT scans and MR images:
- Purely lytic,
destructive and expansive lesions.
- Usually subchondral location,
that is why they are eccentric,
and abut or extend across the sacroiliac joint.
- CT: soft tissue mass that may have thin sclerotic rim.
- Very vascular tumors with enhancement.
- Angiography confirms the prominent vascularity and may be
used for embolization prior to surgical resection.
- Frequently heterogeneous because of the presence
necrosis (low attenuation areas)
hemorrhage (high signal intensity areas on T1 and
T2 weighted sequences or fluid–fluid levels)
Low signal intensity is frequently noted on T2 weighted
images related to the high hemorrhagic and fibrotic
content.
cystic space
Benign notochordal cell tumour: Fig. 5 Fig. 6 Fig. 7 Fig. 8
- Intraosseous benign lesions of notochordal cell origin.
- <4cm.
Limited to the vertebral body,
without extension to the soft tissue .
- Bone structure is respected or slightly densified without osteolysis.
- CT: mild osteosclerosis
- MRI:
T2: hyperintensity
T1: hypointensity.
no enhancement after administration of
intravenous contrast material.
- Most often painless lesions
- No treatment is needed.
- The differential diagnoses are metastases and bone lymphomas.
Hemangioma: Fig. 9
- Composed of thin-walled vessels lined by flat,
bland endothelial cells infiltrating the medullary cavity between bone trabeculae.
- Being cavernous hemangioma the most common benign spinal neoplasm,
(11% of spines at autopsy) usually involving the vertebral body in the lower thoracic and lumbar regions,
sacral involvement is uncommon.
- Commonly multiple.
- Female preponderance (2:1).
- Fourth to sixth decades.
Increase with age.
- Most patients are asymptomatic,
but some lesions can expand and cause pain,
pathologic fractures,
and cord compression.
- CT and MRI
- Coarse vertical or radiating trabecular thickening.
- Typical ones:
Hyperintensitiy on both T1 and T2 –weighted images related
to the amount of adipocytes or vessels and interstitial edema,
respectively.
Epithelioid hemangioendothelioma: Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 Fig. 17
- Rare endothelial vascular neoplasm.
- Intermediate-grade malignant vascular neoplasm.
Clinical course between those of epithelioid hemangioma and angiosarcoma.
- Most frequently during the 2nd and 3rd decades of life.
- Male predilection of approximately 2:1
- Generally,
patients complain of pain and swelling in the affected area.
- Commonly involves the calvarium,
axial skeleton,
and lower limbs.
- In >50% of cases,
multifocal.
- Locally destructive tumor with a variable course,
that is why the choice of treatment is not well established,
although most studies recommend wide surgical resection.
In our case,
patient underwent arterial embolization and surgical incomplete resection demonstrating progressively growth of the tumor during follow up scan.
- Visceral involvement seems to be the most important criterion in predicting a poor prognosis.
- Radiography and CT:
- Lytic lesion without matrix mineralization,
and osseous
expansile remodeling may be seen.
- Localized in cortical or medullary bone.
- Calcification is rare.
- Cortical disruption and extension into soft tissues can be
present.
- Joint invasion is a common feature.
- Homogeneous enhancement.
- T1-weighted: low to intermediate signal intensity with
homogeneous enhancement after gadolinium-based contrast
material.
- T2-weighted: high signal intensity
- The differential diagnosis include angiomatosis,
Langerhans cell histiocytosis,
angiosarcoma,
infection,
myeloma,
metastasis,
and lymphoma.
MALIGNANT
Chordoma: Fig. 18 Fig. 19 Fig. 20 Fig. 21 Fig. 22 Fig. 23
- Rare tumors,
account for 2–4% of all primary malignant bone tumors,
however is the most common primary malignant sacral neoplasm.
- Arises from intraosseous notochordal remnants.
- Slow-growing tumors; commonly discovered as large destructive,
lytic lesions in the midline and associated to soft-tissue mass.
- Localization: 50% originate in the sacrococcygeal region (S4-S5),
35% in the sphenooccipital region; 15% of in the spine.
- Men predominance (2:1)
- Age of 50.
- Histologically they are clear cells with intracytoplasmic vacuoles (physaliphorous cells) and abundant mucin,
both intracellular and extracellular.
In atypical or dedifferentiated chordomas,
the mucinous matrix is replaced by chondroid or osteoid elements
- On CT scans and MR images:
- Lytic lesion,
commonly with internal calcifications,
at both plain
radiography and CT.
- Usually a large soft-tissue extends from the sacral bone to the
presacral space and sacral canal.
- Capable of extending across the adjacent disk space and the
sacroiliac joint.
- T1- weighted: low to intermediate signal intensity
- T2-weighted: prominent increased signal intensity
- Enhancement of the soft-tissue components is moderate,
on
both CT and MR images.
- At angiography demonstrate a prominent vascular stain.
- Low-grade malignancies locally aggressive but infrequently
metastasize.
Lymphoma: Fig. 24 Fig. 25
- Primary bone affection is a rare,
1%–3%,
extranodal manifestation of non-Hodgkin lymphoma (mainly diffuse large B-cell lymphomas).
Much more frequently from late metastatic dissemination.
- Prevalence between 5th–7th decades.
- Male predilection (8:1).
- The appearance of vertebral lymphoma at CT and MR imaging is usually nonspecific.
May have a sclerotic,
lytic,
or mixed appearance.
However,
a focus of bone marrow replacement and a surrounding soft-tissue mass without large areas of cortical bone destruction suggest lymphoma,
caused by tumor spread from the medullary cavity along the small vascular channels that run through the cortex.
Metastatic disease: Fig. 26 Fig. 27 Fig. 28 Fig. 29 Fig. 30 Fig. 31
- The most common vertebral tumors.
- Osteolytic metastases are more frequent than osteoblastic ones.
Some of them have a mixed pattern.
- Osteolytic: usually caused by primary tumors of the lung,
breast,
thyroid,
kidney,
and colon and (in childhood) neuroblastoma.
CT: low Low attenuating lytic areas
MRI:
T1- weighted: low signal intensity
T2-weighted: prominent increased signal intensity
- Osteoblastic: prostate,
breast cancer.
Less frequently by
lymphoma,
carcinoid tumors,
mucinous adenocarcinoma of the
gastrointestinal tract,
pancreatic adenocarcinoma,
bladder
carcinoma,
neuroblastoma,
and (in childhood) medulloblastoma.
CT: sclerotic lesions.
MRI:
T1 and T2- weighted: low signal intensity
- Usually multiple and of variable size.
Ewing’s Sarcoma: More frequent in children.
Lytic,
mixed,
or sclerotic lesions.
MR imaging appearance is nonspecific.
Multiple Myeloma and Plasmacytoma is a difuse monoclonal proliferation of malignant plasma cells of the bone marrow or unifocal tumoral form resepctively.
Other tumors are much more frequent in other location but can also be seen in the sacrum.
Aneurysmal Bone Cyst,
Osteoid Osteoma,
Osteoblastoma,
Chondrosarcoma and Osteosarcoma.