Anaplastic lymphoma kinase-positive anaplastic large-cell lymphoma with involvement of the urinary bladder: a case report and review of literature

We report a unique case of anaplastic large-cell lymphoma (ALCL) involving the urinary bladder in a 22-year-old man. The patient presented with left lower back pain for 4 weeks. The computed tomography (CT) scan demonstrated an exophytic nodule on the left bladder wall and abdominopelvic lymphadenopathy. Histologically, a population of large pleomorphic cells extensively infiltrated the lamina propria of the bladder. These cells were diffusely and strongly immunoreactive for CD30, ALK, EMA, and vimentin, but were negative for AE1/AE3, CK20, CK7, CK5/6, P63, SMA, HMB-45, pan-Melan, S-100, Myo D1, synaptophysin, CD56, desmin, CD15, CD20, Pax-5, and CD3. Few cells exhibited positive immunohistochemical staining of CD45. The patient underwent cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) regime of chemotherapy and achieved a complete remission after four cycles. This case is the tenth documented case of systemic ALCL involving urinary bladder. Due to its rarity, it is important to be aware of the features of ALCL in bladder, and make prompt and accurate diagnosis.