[Detection of a malignant abdominal lymphoma by urine cytology]

Urine cytology performed in a 64 year old man with pain in the left flank and hematuria revealed tumor cells suggesting a malignant lymphoma. Subsequent radiologic and operative findings showed a neoplasm in the left renal region involving intraabdominal and left inguinal lymph nodes. Biopsies from lymph nodes confirmed the presence of a malignant lymphoma probably of histiocytic type. The histologic classification of the tumor is discussed and the rarity of the finding of lymphoma cells in the urine is noted.