Severe hemorrhage secondary to primary, isolated in situ carcinoma of renal pelvis.

Primary transitional cell carcinoma in situ of the renal pelvis is usually found in association with ureteral or vesical neoplasms. However, a case of primary carcinoma in situ of the renal pelvis without previous or concomitant ureteral or vesical carcinoma is presented. Microscopic hematuria is a common finding in cases of carcinoma in situ. Gross hematuria is unusual, but not rare. However, severe hemorrhage (hematocrit 12.1, hemoglobin 3.3 g/dL) as the presenting feature is rare. Diagnosis of such microscopic isolated lesions can be difficult to make pre-operatively. Only after nephrectomy will such a lesion be diagnosed, as was the case in this patient.