Accessory mammary tissue associated with congenital and hereditary nephrourinary malformations

The association between polythelia (supernumerary nipple) and kidney and urinary tract malformations (KUTM) is controversial. Some authors reported this association in newborns and infants. Case-control studies dealing with adult subjects are not found in the literature. The purpose of this study is to determine the frequency of the association between accessory mammary tissue (AMT) and congenital and hereditary nephrourinary defects in an adult population compared to a control group.

The study was performed in 146 white patients (123 men, 23 women) with AMT out of 2645 subjects consecutively referred to us for physical examination. The following investigations were undertaken: ultrasonographic examination of the abdomen and the kidneys, ECG, echocardiogram, roentgenogram of the vertebral column, urinalysis, and other laboratory tests. A sex- and age-matched control group without any evidence of AMT or lateral displacement of the nipples underwent the same examinations.

Kidney and urinary tract malformations were detected in 11 patients with AMT (nine men, two women) and in one control. These data indicate a significantly higher frequency of KUTM in the AMT-affected patients compared to controls (7.53% vs. 0.68%, P < 0.001). A broad spectrum of KUTM was discovered in association with AMT: adult dominant polycystic kidney disease, unilateral renal agenesis, cystic renal dysplasia, familial renal cysts, and congenital stenosis of the pyeloureteral joint.

Accessory mammary tissue offers an important clue for congenital and hereditary anomalies of the kidneys and urinary collecting systems. Patients with AMT should, therefore, be extensively examined for the presence of occult nephrouropathies.