Thin needle biopsy in the diagnosis of ureteral obstruction with malignancy.

Ureteral obstruction after treatment for abdominal cancers is a common situation in which the thin needle biopsy presents an attractive low morbidity alternative to laparotomy for the diagnosis of malignant disease. A negative biopsy is still nonconclusive, although helpful in determining the next step in the patient's management. In our own series, biopsy in the region of ureteral obstruction revealed tumor rather than benign disease in four of five patients. No morbidity was encountered.