= 2nd most common nonlymphoproliferative primary malignant tumor of spine in adults
Peak age: 30 and 70 years; M÷F = 2÷1 to 4÷1
Location: thoracic + lumbar spine >sacrum
Site: posterior element (40%), vertebral body (15%), both (45%)
- large calcified mass with bone destruction
- ± true ossification ← residual osteochondroma
CT:
- low attenuation of nonmineralized portion of tumor
- chondroid matrix mineralization
MR:
- nonmineralized portion of tumor = high water content:
- low to intermediate SI on T1WI
- very high signal intensity on T2WI
- rings and arcs enhancement pattern ← lobulated growth
- extension through intervertebral disk (in 35%)
Rx: en bloc resection
Prevalence: 1÷2,000,000; 2–4% of all primary malignant bone tumors; 1% of all CNS tumors
- 2nd most common primary malignant tumor of spine in adults after lymphoproliferative neoplasms! Highly malignant in children.
Etiology: originates from embryonic remnants of notochord / ectopic cordal foci between Rathke pouch + coccyx (notochord appears between 4th and 7th week of embryonic life and forms nucleus pulposus)
Mean age: 50 (range, 30–70) years; peak in 5th decade; M÷F = 2÷1
Path: lobulated tumor with fluid, gelatinous mucoid substance, recent + old hemorrhage, necrotic areas, occasionally calcifications + sequestered bone fragments contained within pseudocapsule
Histo: [physallis, Greek = bladder, bubble; phoros = bearing]
- typical chordoma: cords + clusters of physaliferous cells (PAS-positive stain) in a lobular arrangement with a large bubblelike multivacuolated cytoplasm containing intracytoplasmic mucous droplets; abundant extracellular mucus deposition + areas of hemorrhage
- chondroid chordoma: cartilage instead of mucinous differentiation of extracellular matrix
Location:
- 50–60% in sacrum (sacrococcygeal chordoma)
- 30–35% in clivus (sphenooccipital chordoma)
- 15% in vertebrae (vertebral chordoma): cervical >thoracic / lumbar spine; vertebral body with sparing of posterior elements
- other sites (5%) in mandible, maxilla, scapula
Site: midline / paramedian
- amorphous calcification (50–75%)
- heterogeneous enhancement
CT:
- low-attenuation within soft-tissue mass ← myxoid-type tissue
- higher attenuation fibrous pseudocapsule
MR (modality of choice):
- low to intermediate intensity on T1WI, occasionally hyperintense ← high protein content:
- heterogeneous internal texture ← calcification, necrosis, gelatinous mucoid collections
- very high SI on T2WI ← physaliferous cells similar to nucleus pulposus with high water content
Angio:
- prominent vascular stain
NUC:
- cold lesion on bone scan
- no uptake on gallium scan
Metastases (in 5–43%) to: liver, lung, regional lymph nodes, peritoneum, skin (late), heart
Prognosis: poor in spite of low grade + slow growth; almost 100% recurrence rate despite radical surgery
DDx: giant notochordal rest (nonprogressive indistinct lesion, normal bone / variable degree of sclerosis, no soft-tissue involvement)
= locally invasive + destructive lesion of clivus
Location: infrasellar midline
- mass of usually T1 hypointensity + T2 signal hyperintensity
- hypointense intratumoral septations
- foci of T1 signal hyperintensity within tumor / periphery ← residual ossified fragments / tumor calcifications, / small collections of proteinaceous fluid / hemorrhage
- posterior extension indenting pons
DDx: cartilaginous tumor (more lateral location, at petrooccipital synchondrosis, curvilinear calcifications)
Sacrococcygeal Chordoma (50–70%)
= large destructive sacral mass with 2ndary soft-tissue extension
◊Most common primary sacral tumor after giant cell tumor!
Peak age: 40–60 years; M÷F = 2–3÷1
Path: slow-growing tumor → large size at presentation
- clinically indolent and subtle; rectal bleeding (42%)
- low back pain (70%); sciatica + weakness in hip / lower limbs ← sacral root compression
- constipation, frequency, urgency, straining on micturition ← compression by tumor
- autonomic dysfunction → urinary / fecal incontinence
- palpable sacral mass on digital examination (17%)
Location: predominantly in 4th + 5th sacral segment
- presacral mass with average size of 10 cm extending superiorly + inferiorly; rarely posterior location
- displacement of rectum + bladder
- solid tumor with cystic areas (in 50%)
- amorphous peripheral calcifications (15–89%)
- secondary bone sclerosis in tumor periphery (50%)
- honeycomb pattern with trabeculations (10–15%)
- may cross sacroiliac joint
X-ray:
- osteolytic midline mass in sacrum + coccyx associated with soft-tissue mass and calcifications
CT (useful for defining extent of bone involvement):
- bone destruction associated with lobulated midline soft-tissue mass
- areas of low attenuation within mass ← high water content of myxoid properties
MR:
- hypo- / isointense mass relative to muscle on T1WI:
- intrinsic hyperintense areas on T1WI ← hemorrhage or myxoid / mucinous collections
- hyperintense mass similar to nucleus pulposus on T2WI ← high water content:
- dividing septa + hemosiderin of low signal intensity
- heterogeneous often moderate enhancement
The combination of high T2 signal intensity in a lobulated sacral mass that contains areas of hemorrhage and calcification is strongly suggestive of a chordoma!
Prognosis: 7–10 years average survival; 50–74% 5-year survival rate (in adulthood); 52–64% 10-year survival; 52% 20-year survival
Dx: fine-needle aspiration biopsy
Rx: radical surgical excision (most critical); radiation therapy; 70% rate of local recurrence after excision
DDx:
- Primary neural tumor: schwannoma, neurofibroma, meningioma, myxopapillary ependymoma (from within spinal canal, more intense enhancement)
- Primary bone tumor:
- Giant cell tumor (2nd most common primary, upper sacrum, may be eccentric, ± extension across SI joint, low-to-intermediate T2 intensity ± fluid-fluid levels)
- Chondrosarcoma (off midline from sacroiliac joint space cartilage, heterogeneous T2 SI, no hemorrhage)
- Aneurysmal bone cyst
- Osteoblastoma
- Lymphoma
- Metastasis, plasmacytoma
- Soft-tissue neoplasm: atypical hemangioma, prostatic carcinoma, osteosarcoma, osteomyelitis
Sphenooccipital Chordoma (15–35%)
Age: younger patient (peak age of 20–40 years); M÷F - 1÷1
- orbitofrontal headache
- visual disturbances, ptosis
- 6th nerve palsy / paraplegia
Location: clivus, sphenooccipital synchondrosis
- bone destruction (in 90%): clivus >sella >petrous bone >orbit >floor of middle cranial fossa >jugular fossa >atlas >foramen magnum
- reactive bone sclerosis (rare)
- calcifications / residual bone trabeculae (20–70%)
- soft-tissue extension into nasopharynx (common), into sphenoid + ethmoid sinuses (occasionally), may reach nasal cavity + maxillary antrum
- variable degree of enhancement
MR:
- large intraosseous mass extending into prepontine cistern, sphenoid sinus, middle cranial fossa, nasopharynx
- posterior displacement of brainstem
- usually hypo- / isointense to brain / occasionally inhomogeneously hyperintense on T1WI
- hyperintense on T2WI
- ± CHARACTERISTIC honeycomb enhancement pattern
Prognosis: 4–5 years average survival
DDx: meningioma, metastasis, plasmacytoma, giant cell tumor, sphenoid sinus cyst, nasopharyngeal carcinoma, chondrosarcoma
Vertebral / Spinal Chordoma (15–20%)
◊More aggressive than sacral / cranial chordomas
Age: younger patient; M÷F = 2÷1
- low back pain + radiculopathy + retention of urine
Location: cervical (8% – particularly C2), thoracic spine (4%), lumbar spine (3%)
Site: midline centra sparing posterior elements; arising in perivertebral musculature (uncommon)
- destructive expansile lesion of vertebral body:
- + epidural soft-tissue mass of collar button / mushroom / dumbbell shape over several segments
- often incomplete sparing of disk spaces to involve adjacent bodies (10–14%) simulating infection
- exophytic anterior soft-tissue mass
- expansion into neural foramen mimicking nerve sheath tumor
- solitary midline spinal mass
- sclerosis / “ivory vertebra” in 43–62%
- total destruction of vertebra, initially without collapse
- amorphous peripheral calcifications in 40%
Cx: complete spinal block
Prognosis: 4–5 years average survival
DDx: metastasis, primary bone tumor, primary soft-tissue tumor, neuroma, meningioma