Giant solitary extradural plasmacytoma of the skull: illustrative case

Abstract

BACKGROUND Solitary extradural plasmacytoma of the skull (SEPS) is an extremely rare entity with only 35 cases reported in the English-language literature. SEPS is a rare presentation of plasma cell dyscrasias, accounting for 4% of plasma cell tumors. The diagnosis of solitary plasmacytoma requires exclusion of multiple myeloma (MM) and prompt diagnosis and treatment. OBSERVATIONS The authors describe the case of a 52-year-old man with SEPS. He presented with a painless, progressive, soft swelling mass in the left parietal region. Magnetic resonance imaging revealed a left frontotemporal extra-axial lesion that involved the ipsilateral orbital apex and posterior ethmoidal cells. Biological studies did not reveal features suggestive of MM. A diagnosis of SEPS was based on microscopic examination and immunohistochemical analysis after surgery. The patient had an excellent recovery and was discharged the day after surgery without neurological deficit. LESSONS SEPS is a potentially curable disease, and total resection with or without radiotherapy is associated with a good prognosis and long-term recurrence-free survival. Distinction between SEPS and MM is of paramount importance because the prognosis and treatment differ.