A Case of p63 Positive Diffuse Large B Cell Lymphoma of the Bladder.

Diffuse large B cell lymphoma (DLBCL), currently the most common type of non-Hodgkin lymphoma (NHL), is an aggressive B cell neoplasm that typically presents in older adults as a rapidly enlarging mass. The enlarging mass typically represents a lymph node, although extranodal disease can occur in a significant percentage (40%) of cases. The most common extranodal sites of involvement include the gastrointestinal tract and skin; primary bladder lymphoma represents only 0.2% of extranodal non-Hodgkin lymphomas. We report a case of diffuse large B cell lymphoma occurring in the bladder of an 83-year-old gentleman with an initial presentation of hematuria. This neoplasm displayed large, atypical cells with vesicular chromatin and prominent nucleoli that involved the bladder mucosa with invasion into muscularis propria, prostate, and urethra. Positive staining for p63 initially raised suspicion for poorly differentiated urothelial carcinoma; however, lack of staining for pancytokeratin and positive staining for LCA, CD20, CD79a, and PAX-5 confirmed the diagnosis of diffuse large B cell lymphoma. Though it does not occur in all cases, p63 can be positive in a significant percentage of cases of DLBCL; therefore, a diagnosis of lymphoma remains an important entity on the differential diagnosis of aggressive and particularly poorly differentiated neoplasms. [ABSTRACT FROM AUTHOR]