Primary Osteosarcoma of the Skull Base in a Pregnant Patient.

An 18-year-old female who was 14 weeks pregnant first noted vision loss in her left eye six days prior to admission. Ophthalmologic examination revealed 20/20 vision in the right eye and count fingers vision in the left eye. A marked relative afferent pupillary defect was present in the left eye. Ophthalmoscopic examination revealed a trace optic nerve pallor temporally in the left eye without associated disc oedema or haemorrhage. Magnetic resonance imaging of the brain demonstrated a heterogeneous mass of the left sphenoid sinus extending superiorly causing compression of the intracranial portion of the left optic nerve, and laterally into the left cavernous sinus. The patient underwent transphenoidal resection of the tumour whose histologic morphology revealed a grade 2 osteosarcoma. Following resection, vision returned to 20/20 in the left eye. The patient has been treated with chemotherapy with close monitoring of her pregnancy.