Use of immunohistochemistry for identification of primary lymphoma of the bladder.

Primary lymphoma of the bladder is a rare entity, and when found in such an unusual location it frequently is difficult to distinguish between a lymphoma and an undifferentiated carcinoma. Immunohistochemical staining techniques have been used to identify tumor cell origins when the tissue type or a primary site of involvement is unknown. We report a case of primary lymphoma (nonHodgkin's type) of the bladder and the use of immunohistochemical staining to distinguish definitively tissue type and then specific immunotype.