Petrous apex non-secretory plasma cell myeloma with aberrant cytokeratin expression.

Multiple myeloma is a monoclonal proliferation of plasma cells with common involvement of vertebrae, ribs and skull vault. However, involvement of skull base is relatively uncommon and myeloma manifesting initially as a petrous apex mass is distinctly rare. We report a rare case of non-secretory multiple myeloma in a 52-year-old Egyptian male presenting primarily as a right petrous apex mass with abducens nerve palsy. Additionally, neoplastic cells aberrantly expressed cytokeratin. Although rare, plasma cell myeloma should be considered in the differential diagnosis of petrous apex masses.