Anaplastic large cell lymphoma: a unique presentation with urinary bladder involvement: a case report.

Anaplastic large cell lymphoma (ALCL) is a T-cell lymphoma composed of large pleomorphic CD30-positive cells. While systemic ALCL frequently involves extranodal sites, involvement of the urinary bladder is extremely rare. We report a case of systemic ALCL presenting with bladder involvement. A 28-year-old man presented with hematuria, dysuria, and lower abdominal pain. Imaging revealed pelvic lymphadenopathy and a thickened bladder wall. Bladder biopsies showed diffuse infiltration of the lamina propria by large pleomorphic cells, with preservation of the overlying urothelium. Immunohistochemistry demonstrated cell membrane and Golgi region staining for CD30 and epithelial membrane antigen. This is the first documented instance of systemic ALCL presenting with bladder symptoms.