Supernumerary nipples and Becker's nevus : a previously undescribed association. Report of 9 patients including a subset with uropathies

Supernumerary nipple (SN), or polythelia, is a congenital anomaly of ectodermal origin, and which is clue for a broad spectrum of kidney and urinary tract malformations. Becker's nevus (BN) is a hamartomatous defect of ectomesodermal origin usually occurring after puberty. Here we describe the clinical association between SN and BN and discuss the further association of these two cutaneous defects with urinary tract malformations. We have observed that 9 out of 169 (5.32%) adult Caucasian subjects with SN had clinical evidence of BN. An ipsilaterality of the two defects was recorded in 8 out of the 9 patients. Moreover, 2 out of the 9 had concomitant occurrence of uropathies, in the form of familial renal cysts, associated with ipsilateral SN and BN. Our observation deals with an association never-before encountered, between SN and BN. The further concomitance of renal cysts represents a previously unreported association with a hypothetic syndrome-like pattern. A possible explanation may be in the developmental field defect concept reflecting a disturbance early in embryogenesis in the specific polytopic fields involved. We suggest the acronym SNUB (Supernumerary Nipple, Uropathies - for familial renal cysts - and Becker's nevus) for this association.