Schwannoma with monoclonal plasma cell infiltration.

The authors report a very rare case of a vestibular schwannoma with an infiltrate of monoclonal plasma cells. A 45-year-old woman underwent routine excision of a presumed vestibular schwannoma. Histological analysis revealed the presence of a distinct lambda light chain restricted plasma cell population within the schwannoma. The light chain restriction and polymerase chain reaction-demonstrated monoclonality of the plasma cell population suggested the co-occurrence of a plasma cell neoplasm within a schwannoma. A search for systemic disease of plasma cell origin was unremarkable. A search of the literature suggests that this is the first report of such an occurrence.