Chordomas are locally invasive slow growing malignant tumors that arise from the remnant of the primitive notochord. They occur most commonly in the skull base (clivus) and lower spine; approximately 40% of chordomas and chondrosarcomas arise in the clivus (directly below the sella turcica and pituitary gland). Chordomas can behave quite aggressively and are often extensively invasive into surrounding skull base structures. A small subset of patients (~10%) may develop metastases to distant sites beyond their site of origin.
The most common presenting symptom of a clival chordoma is double vision. Less common symptoms may include visual loss, hearing loss, difficulty swallowing, facial numbness, incoordination and motor weakness and nasal congestion.
These skull base tumors are best diagnosed by MRI and CT scans which will clearly show the extent of tumor and bony destruction. Focused MRIs of the pituitary region, sinuses, temporal bones or internal auditory canals may be indicated to obtain better anatomical detail of a chordoma. Other tests may also be needed prior to surgery such as angiography (typically now performed as a CT angiogram or an MR angiogram), visual field tests, an audiogram or hormonal tests.
Initial treatment for a clival chordoma is with surgical removal or debulking. Given their midline location, most clival chordomas and chondrosarcomas are best removed via an endonasal endoscopic approach. However, some extensive and/or laterally placed chordomas may require different skull base surgical approaches. Because chordomas typically invade the bone and dura of the skull base as well as cavernous sinus area, complete surgical resection is often not possible and continued growth of residual tumor is common. Extensive surgery can certainly improve long term survival but over aggressive tumor removal can be associated with significant neurological complications. Most recurrent or residual chordomas are treated with Stereotactic Radiotherapy (SRT), stereotactic radiosurgery (SRS) or proton beam radiation. Chemotherapy is generally ineffective for treating chordomas although clinical trials of some experimental chemotherapies are available.
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