Ectopic breast tissue presenting as an anal polyp.

Mammary glands begin developing during the sixth week of embryogenesis and extend as 2 surface thickenings from the axillary to inguinal regions.1 At 2–3 months' gestation, these thickenings develop further as mammary ridges. Supernumerary breasts or nipples, polymastia and polythelia respectively, occur in 1%–2% of the general population.2–4 They may arise anywhere along the mammary ridges, developing from extramammary buds or, more rarely, from tissue that was displaced from these ridges.1 We report a case of an unusual anal polyp presenting as an intermittently prolapsing lesion. The pathological features were those of breast tissue.