An uncommon location for accessory breast tissue: inner thigh

Abstract

Sir: Polymastia or accessory breast tissue has been described in humans for centuries. Ectopic breast tissue can occur anywhere along the bilateral primitive embryonic milk line, extending from the axilla to the groin [3]. Its reported incidence varies between 0.4–6 %, so it is an infrequent clinical finding [1]. Accessory mammary tissue has been repeatedly reported to occur in axilla, chest, abdominal wall, and vulva. A 64-year-old female patient presented with a lump in the inner aspect of her right thigh present for at least 10 years. The only complaint was the friction that the lump caused while walking. Physical examination revealed a skin colored dermal nodule 2 cm in diameter with a papillomatous appearance centrally (Figs. 1 and 2). An underlying 5cm subcutaneous firm mobile nontender mass beneath this nodule was present in the medial side of her right thigh at the junction of the upper one third and lower two thirds of the thigh (Figs. 1 and 3). Medical history was unremarkable except for hypertension. The authors diagnosed this as an accessory nipple associated with glandular tissue. The condition was explained to the patient but she refused any imaging modalities and did not accept surgical treatment. In the 5-week-old human embryo, it is reported that ectodermal streak develops on the ventral surface of the embryonic trunk and extends from the axilla to the groin bilaterally [1, 3]. Most of this milk line disappears soon after its formation but persists bilaterally only in the thoracic region to form future breasts [1, 3]. On occasion, residual fragments may persist and give rise to accessory breast tissue along the original distribution of the milk line in other regions [1, 3, 5]. Less commonly, accessory breast tissue has also been reported to occur in locations outside the milk line: face, posterior neck, chest, mid-back, buttock, vulva, flank, hip, posterior and/or lateral thigh, shoulder, and upper extremities [4, 5]. The incidence of each anatomic location varies [5]. The authors concluded that there were two other reported cases with accessory breast tissue present in the inner thigh after reviewing the drawing that Patten used in his book printed in 1946 [4]. The accessory breast tissue may take several forms [3]. This patient possibly has a supernumerary breast with a nipple associated with glandular tissue located in the medial side of her right thigh. Alghamdi et al. reported surgical excision percentage for accessory breast tissue to be 28% in their studies. The other Eur J Plast Surg (2008) 31:339–340 DOI 10.1007/s00238-008-0286-3