Plasmacytoma of the Skull-base: A Rare Tumor.

Plasmacytoma of the skull-base is a rare entity. Differential diagnosis includes chordoma, osteosarcoma, carcinoma nasopharynx, meningioma, metastatic carcinoma, lymphoma, and multiple myeloma. Accurate and precise diagnosis is extremely important for plasmacytoma of the skull-base as its treatment and prognosis is different from other skull-base lesions. A 41-year-old man presented with concerns of headache, diplopia, and left eye strabismus. A magnetic resonance image (MRI) of his brain showed a large expansile mass measuring 51 mm involving the clivus and central skull-base. Trans-sphenoidal tumor decompression was done. A biopsy confirmed the plasmacytoma. A positron emission tomography-computed tomography (PET-CT) scan showed a single 2-(18F) fluoro-D-glucose (FDG) avid lesion at the skull-base. The results of all other relevant investigations such as hemoglobin, renal function test, serum calcium, serum protein immunoelectrophoresis, serum quantitative immunoglobulin, bone marrow biopsy, serum lactate dehydrogenase, and beta-2 microglobulin levels were within normal limits. He was treated with radical radiotherapy. He developed complete clinical response after radiotherapy.