Chondroid Chordoma
- Background:
- Chordomas and chondrosarcomas constitute only 6% of all skull-base tumors. Both may have similar clinical presentations and radiological features but different behaviors and outcomes.
- Histologically, there are two subtypes of chordomas: 1) classical and 2) chondroid. The chondroid type has better prognosis.
- Chondroid chordomas are characterized by islands of cartilage formation, whereas classic chordomas consists of tumor cells in lacunae that are embedded in hyaline cartilage-like stroma.
- Immunohistochemical stains show positive reactivity pattern of S100 and cytokeratin AE1/AE.
- Clinical Presentation:
- Patients usually present with and diplopia (CN 6)
- Key Diagnostic Features:
- Lobulated high-T2 enhancing clival mass originating with no calcifications
- Differential Diagnosis:
- Invasive pituitary macroadenoma originates in the sella nd involves the pituitary gland. It extends into the sphenoid sinus but not the prepontine cistern.
- Skull base chondrosarcoma arises off midline at the petro-occipital fissure. Calcifications are more common.
- Skull base meningioma has hyperostosis of adjacent bone. Homogeneous enhancement with "dural tail“. Commonly causes narrowing of encased vessels.
- Sellar haemangioma may show the same signal characteristics, but it is located within the cavernous sinus. Also, it is seen in younger age groups.
- Treatment:
- Surgical resection (conventional surgery vs. endonasal transclival resection)
- Complete excision difficult due to close proximity of critical structures
- Significant occipital condyle extension may require surgical fusion & instrumentation
- Proton beam radiotherapy: Post-op and unresectable tumors
- Surgical resection (conventional surgery vs. endonasal transclival resection)
