Chordoma

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.