Primary Classical Hodgkin Lymphoma of the Urinary Bladder: Expanding the Spectrum of Bladder Lymphoid Neoplasms.

Primary classical Hodgkin lymphoma of the urinary bladder is an extremely rare entity, with only a few documented examples in the literature. Most of the previously reported tumors represent secondary bladder involvement by systemic classical Hodgkin lymphoma, whereas only two tumors have been documented as primary classical Hodgkin lymphoma of the bladder. Here, we report a 71-year-old woman who presented with hematuria and urinary incontinence. PET/CT revealed a 44 × 53 × 60 mm hypermetabolic mass on the posteroinferior wall of the bladder, invading the anterior vaginal wall (SUVmax 18.2), with only regional pelvic lymph node involvement (SUVmax up to 8.8). Histopathologic examination of the transurethral resection specimen showed classical Reed-Sternberg cells within a mixed inflammatory infiltrate. Immunohistochemically, the tumor cells were positive for PAX5 (weak), CD30, CD15, and negative for LCA, CD20, CD79a, CD3, CD5, CD10. The tumor cells were also positive for Epstein-Barr virus (EBV)-encoded RNA (EBER) by in situ hybridization. In the absence of systemic involvement, the patient was diagnosed with primary classical Hodgkin lymphoma of the bladder. This rare presentation highlights the importance of considering classical Hodgkin lymphoma in the differential diagnosis of bladder tumors with atypical morphology.