Myxoid Sarcoma of the Skull Base

These images show a massive, heterogeneously enhancing, T2 hyperintense mass with large intra and extraosseous components markedly expanding the nasal cavity and paranasal sinuses (left greater than right), sella and cavernous sinuses, left petroclival synchondrosis with large dumbell shaped extension into the left cerebellopontine angle and left mastoid. There is moderate mass effect on the left brachium pontis and temporal lobes and marked left proptosis. There is mild mass effect on the optic chiasm. There is no restricted diffusion. Pathology showed a myxoid sarcoma. These lesions are characterized by T2 hyperintensity and enhancement which is seen here. They are usually seen in young to middle age adults as seen here, but they are most commonly located in the lower extremities with the skull base location being very uncommon.