A Case of Recurrent Multiple Myeloma as Testicular Plasmacytoma Without Systemic Disease.

Plasma cell neoplasms include various conditions ranging from indolent conditions such as monoclonal gammopathy of undetermined significance (MGUS) to more aggressive forms such as multiple myeloma (MM). The World Health Organization classifies plasmacytomas into two types: solitary osseous plasmacytoma (SOP) and extramedullary plasmacytoma (EMP). Most primary EMPs occur in the upper gastrointestinal tract, head and neck, upper respiratory system, central nervous system, lungs, liver, spleen, and kidneys. However, the occurrence of EMP involving the testis site is quite rare. Given the rarity of testicular plasmacytoma, there is no consensus on the standard of treatment for this diagnosis. Most EMP is radiosensitive, with few localized types responding to surgical intervention. Tumor recurrence and disseminated infiltration are treated with adjuvant chemotherapy after radiation or surgery. Our patient has a unique presentation of an individual who developed recurrent myeloma of the testis 12 years after his initial diagnosis of myeloma.