Primary Malignant Lymphoma of the Epididymis: A case report of involvement by diffuse large B cell lymphoma

Lee, Mi Ja; Kee, Keun Hong

Abstract

Isolated involvement of the epididymis by malignant lymphoma is very rare and almost invariably is associated with lymphoma in the adjacent testis. To date, there are four case reports of primary epididymal lymphoma. In this case, 74-year-old man presented with a 3 cm, painless left epididymal swelling. Extensive staging work-up showed no evidence of extraepididymal spread. The epididymectomy was performed. The enlarged epididymis was firm and entirely replaced by whitish gray homogenous tumor measuring 1.8x0.9 cm. Microscopically, the tumor revealed an interductal, highly cellular infiltration, distorting the normal epididymal architecture. The lymphomatous infiltrate was polymorphic, though the predominant cell type exhibited a large irregular and vesicular nucleus. In many areas, small reactive lymphocytes, eosinophils, and occasional plasma cells were interspersed among the neoplastic cell population. Mitoses were frequent. The small lymphoid cells focally infiltrate through the wall of some tubules and small veins. A variable pattern of sclerosis was present throughout much of the tumor. Also there were non-specific granulomas. Immunohistochemical staining revealed that the large cel1s were B cells (CD20 positive) and conclusively lambda light chain restriction. The smaller reactive lymphoid cells were composed of a mixture of B cells and T cells (CD3, UCHL-1 positive). The DNA analysis of lymphoma shows a diploidy DNA content. S phase fraction is 21%. To date, the patient, who treated with chemotheraphy, remains well 9 months after diagnosis. Most lymphomas of testis and epididymis occur in older men, have an intermediate or high grade, diffuse histology, disseminate early, and follow an aggressive clinical course. This case is some similar to the conventional most lymphomas of testis and epididymis. But unusual fetures included that the tumor showed only confined to the epididymis and marked sclerosis.