Tumor biology and incidence
- Low-grade malignant tumor
- Generally located at base of skull (clivus), sacrum, or spine (less common)
- Thought to arise from primitive notochordal remnants in the axial skeleton
- Present in a central, axial-based location, most often anteriorly
- Cumulative case count published in The Burden of Musculoskeletal Disease (AAOS) identified 2,339 chordomas over a period of 20 years, or annual incidence of 117 chordomas in the US within the studied population
- Other estimates as high as 300 cases per year
Age
- Most occur in older patients, especially those older than age 40
- Rarely occur before age 30
Gender
M:F = 2:1
Presentation
- Symptoms generally of long duration due to slow growth of lesion and delay in diagnosis
- Symptoms usually nonspecific, depending on location of tumor
- Cervical spine: Hoarseness, dysphagia, bleeding
- Sacrum: Vague low back pain, constipation, lower extremity radiculopathy, palpable mass
- Bowel and bladder dysfunction resulting from local organ mass effect or autonomic dysfunction
- Autonomic dysfunction can result as the tumor compresses the adjacent sympathetic or parasympathetic outflow
- Obtain history of treatment for degenerative disc disease or coccydynia
- Obtain history of bowel, bladder, and sexual function
Physical findings
- Abnormal rectal tone, perineal sensation possible
- Soft tissue mass may be palpable on rectal exam
Plain films
- Lesion may be missed on plain films; changes generally subtle
- Findings may be masked by overlying abdomina/bowel gas on AP of pelvis
Site
- Sacrococcygeal lesions
- Spheno-occipital lesions
- Vertebral body lesions (in descending order of occurrence): cervical, thoracic, lumbar
Size
Slow growing lesion; can be quite large by time of diagnosis
Tumor effect on bone
Local lytic destruction of bone; extension into surrounding soft tissues
Bone response to tumor
Sclerotic, irregularly scalloped bony margin
Matrix
Calcified secondary to calcification of necrotic tissue/debris within tumor (rare)
Cortex
Cortical breakthrough (common)
Soft tissue mass
Common; more apparent on MRI than on plain films
CT scan
- Useful for assessing degree of osseous involvement, as well as proximity of tumor mass to adjacent pelvic organs
- Chest CT for systemic staging
MRI
- Need multiple axes to accurately stage extent of lesion and plan surgery
- Superior soft tissue resolution with respect to involvement of neurovascular structures within pelvis and spinal canal
- Chordomas mucinous; lesions typically appear hypointense on T1-weighted images and hyperintense on T2-weighted images
- Characteristic lobular, heterogeneous features
- Occasionally, contrast fluid-fluid levels can be identified in cystic portions of mass
Differential diagnosis
- Metastasis
- Chondrosarcoma
- Myeloma
- Lymphoma
- Giant cell tumor
Natural history
- Will continue to grow; symptoms related to location
- May dedifferentiate into higher-grade lesion with sarcomatous component (rare)
- Difficult to resect, leading to frequent local recurrence
- Local recurrence in lumbosacral plexus devastating complication
- Radiation plus local resection may reduce risk of local relapse
- Metastases usually very late feature
Pathology
- Gross: Lobulated, myxoid tissue
- Microscopic: Tumor cells are in sheets or cords in an abundant myxoid stroma
- Cells often vacuolated, displacing the nucleus eccentrically
- Physaliferous cells may be present
- Cytological atypia may be present; no clinical significance
- High mucin content within cytoplasm and in matrix renders a deep, eosinophilic appearance on H&E stained sections.
- Chondroid appearance, particularly in clival-based tumors; may indicate a better prognosis
- Dedifferentiated form of chordoma has poor prognosis.
- Characterized immunohistochemically by S100 and epithelial membrane antigen positivity
Diagnosis and treatment
- Biopsy, in consultation with musculoskeletal surgical oncolgist
- Avoid transrectal biopsy; would necessitate rectal resection and colostomy
- Avoid tumor spillage by using posterior needle biopsy
- Maintain of treatment: surgical resection with clear margins; chemotherapy ineffective
- Wide resection can be curative; however 50% recurrence rate has been reported, which reduces chance of cure for patient
- Resection of upper sacral lesions (S2 or above) carry an increased risk of blood loss, major complications, and longer ICU stays
- Radiation therapy possibly useful in cases with microscopically positive margins of resection, palliative treatment of unresectable lesion
- Median survival is 6 years
- Overall survival rates: 70% at 5 years, 40% at 10 years
- After development of metastases, median survival diminishes greatly
Recommended reading
Casali PG, Messina A, Stacchiotti S, et al. Imatinib mesylate in chordoma. Cancer. 2004 Nov 1;101(9):2086-97.
Devin C, Chong PY, Holt GE, Feurer I, Gonzalez A, Merchant N, Schwartz HS. Level-adjusted perioperative risk of sacral amputations. J Surg Oncol. 2006 Sep 1;94(3):203-11.
Bullough P, ed. Orthopaedic Pathology. 4th ed. Philadelphia, PA: Mosby, 2004.