Primary mucosa-associated lymphoid tissue (MALT) lymphoma arising from the male urethra. A case report and review of the literature

Primary non-Hodgkin's lymphomas rarely arise from the lower urinary tract, the urethra being the most uncommon site of origin. Herein, we report the immunohistochemical findings of a case of primary marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) arising from the male urethra. To clarify the clinicopathological findings of primary urethral lymphoma, we reviewed 14 previously reported cases. A 56-year-old man presented with gross hematuria. Cystourethroscopy demonstrated a nodular bulge of the urethral wall. Histologically, a transurethral biopsy specimen showed a dense lymphoplasmacytoid infiltrate in the urethral mucosa. The tumor cells were composed of centrocyte-like cells, plasma cells and plasmacytoid cells. A few plasma cells contained intracytoplasmic pseudoinclusions (Dutcher bodies). Immunohistochemical study revealed monotypic intracytoplasmic kappa-light chain in the plasma cells and plasmacytoid cells. The patient received a total of 50 Gy extrabeam irradiation. Follow-up 21 months later did not disclose any sign of local or other recurrences.