Chordomas originate from remnants of the notochord during embryonic development. During the embryonic period, the upper part of the notochord extends to the base of the skull, including the sphenoid and occipital bones. Some portions reach the intracranial surface and are connected to the dura mater above the sella turcica, while the occipital portion can extend to its inferior surface (the pharyngeal side). Other portions may lie between the basal skull bones and the pharyngeal wall. The lower part of the notochord is distributed predominantly in the central and paracentral regions of the sacrococcygeal area. As a result, chordomas commonly develop in these areas, with the clivus at the cranial base and the sacrococcygeal region being the most frequent sites, followed by spinal involvement.
Chordomas are low-grade malignant tumors characterized by slow growth but are locally aggressive. They are most commonly observed in individuals aged 30 to 40 years, with no significant sex predilection.
The clinical manifestations of intracranial chordomas vary depending on the tumor's location and its direction of growth:
- Sellar Chordomas: Hypopituitarism is the main presentation, manifesting as symptoms such as erectile dysfunction, amenorrhea, and weight gain. Compression of the optic nerve may lead to primary optic atrophy, decreased vision, and bitemporal hemianopia.
- Parasellar Chordomas: These primarily affect cranial nerves III, IV, and VI, with abducens nerve involvement being the most common.
Gross pathological examination often reveals a friable, lobulated, and rounded tumor with a pseudocapsule. Microscopic pathology shows tumor cells with a signet-ring appearance. Chordomas can be classified into three types: conventional chordoma, chondroid chordoma, and dedifferentiated chordoma.
Typical CT imaging features include expansile osteolytic destruction, often accompanied by adjacent soft tissue masses, scattered calcifications, and bone fragments. MRI findings demonstrate low signal intensity on T1-weighted images and high signal intensity on T2-weighted images, which better delineate tumor boundaries and their relationship to cranial nerves.
Because chordomas are relatively resistant to radiation therapy, conventional radiotherapy usually serves a palliative role. Endoscopic tumor resection via transnasal and/or transoral approaches remains the primary treatment method.