Abstract / Summary
Abstract Background Primary lymphomas of the urinary bladder are rare, most of which are low-grade B-cell lymphomas. Primary anaplastic large cell lymphoma (ALCL) with bladder involvement is extremely rare, with most cases seen in adult patients. Here, we report a case of ALK-positive ALCL in a 14-year-old male. Case presentation A 14-year-old male presented with several months of gross hematuria that had become painful. Computed tomography (CT) urogram showed a mass-like thickening of the anterior bladder wall. Cystoscopy showed a 3.5-cm pedunculated lesion at the bladder dome; transurethral excision was performed. Histology revealed sheets of large pleomorphic cells with horseshoe-shaped nuclei and brisk mitotic activity. Tumor cells were positive for CD4, CD5, and CD30 (diffuse/strong) and negative for CD45. ALK immunostain showed nuclear and cytoplasmic staining. A diagnosis of ALK + ALCL was made. Staging CT was negative for disease. The bone marrow was uninvolved. The patient received multi-agent chemotherapy including brentuximab vedotin. A 2-month follow-up cystoscopy showed a well-healed resection site. Seven months after completing therapy, the patient had recurrent hematuria. Cystoscopy revealed an ulcerated lesion, but biopsies were reactive and showed no lymphoma. The patient remains under surveillance with urology and oncology. Conclusion Primary bladder ALK + ALCL is exceedingly rare in children. Uniform CD30 positivity and ALK positivity are the key diagnostic clues.