Primary sclerosing lipogranuloma with broad necrosis of the scrotum

A-25-year-old man was admitted because of a painless tumor of the scrotum. The patient denied a history of exogenous material injection and trauma in the scrotum. Physical and radiological examination revealed a mass in the scrotum, and blood laboratory tests showed no significant findings except for mild eosinophilia (5.6%). Resection of the mass was performed. The mass was isolated and located in the subcutaneous tissue of the scrotum. The mass was rectangular and symmetrical, and measured 65 x 45 x 15 mm. Histologically, the mass was composed of adipose tissue with fibrosis. Many epithelioid granulomas with multinucleated giant cells of foreign body and Langhans' types and heavy infiltrates of lymphocytes and eosinophils were recognized. Characteristically, the lesion showed broad coagulative and lytic necrosis. Congestion and edema suggestive of ischemia were seen in some areas. Special stains for acid-fast bacteria, gram-positive bacteria and fungi failed to detect any microorganisms. Polymerase chain reaction for mycobacterium tuberculosis revealed no reaction products. Immunohistochemically, the majority of lymphocytes were CD45RO-positive T cells, and S-100 protein-positive cells and CD68-positive macrophages were scattered in small amounts. The appearances were typical for sclerosing lipogranuloma except for the necrosis. Although the pathological mechanism of the broad necrosis is unclear, the necrosis might be the result of ischemia. Our case suggests that primary sclerosing lipogranuloma of the scrotum might show broad necrosis, and that T-cell-mediated immune response might play a part in the formation of lipogranuloma.