Lower pole hydronephrosis stimulating neoplasm in duplicated kidney.

An interesting case of nonobstructive lower pole hydronephrosis associated with reflux and simulating a neoplasm is presented and discussed. Advanced hydronephrosis localized to one portion of a duplicated kidney in adults may simulate a renal neoplasm on intravenous pyelogram. Upper pole hydronephrosis is a well-described clinical entity and is prominent in the differential diagnosis of renal mass lesions. Although lower pole hydronephrosis occurs more commonly, it has only rarely been reported to cause confusion in the diagnosis of renal masses. An interesting case of lower pole hydronephrosis simulating a neoplasm is presented and discussed.