Incidental Discovery of Supernumerary Breast Tissue in Dissection Course: Case Report and Review of Literature

Abstract

Accessory mammary tissue is rare in the clinical practice, and may be present as polythelia or polymastia. Polythelia (one or more supernumerary nipples) is a congenital condition, being detectable during childhood. Polymastia (more than two mammary glands) may not be evident until puberty. During the seventh gestational week, the embryologic mammary line (“milk line”) is represented by two thickened strips of ectoderm, which extend from the axilla to the inguinal region, and only a small portion of this line might persist. In case it doesn't disappear, an accessory breast may develop anywhere along the streak. The objective of this work is to report the finding of accessory breasts in the lower thoracic wall of a body belonging to the Body Donation Program at UFCSPA. The body in question was female, Caucasian, 84 years old, with no history of breast cancer. During dissection, two accessory breasts were identified in the lower thoracic wall, below the chest muscles, equidistant from each other, the right one measuring 3,0 × 2,7cm, and the left measuring 2,5 × 2,5cm. Samples for histological analysis were extracted and using hematoxylin and eosin staining. Breast tissue was identified, confirming the hypothesis of polymastia. Accessory breast tissue is an uncommon finding in women (2–6%) as well as in men (1–3%). Usually it develops along the course of the embryologic mammary line, and may be solitary or multiple, arising on one or both sides of the line. They are usually asymptomatic, not demanding medical intervention. However, in cases of development in females, the surgical resection of the accessory breast may be necessary, once there is greater symptomatology due to the influence of hormonal variations. There are reports of neoplasic proliferation in this tissue (0,3%). Therefore, this finding becomes important in the medical practice, since it should be remembered as a possible source of malignant neoplasm, and in the differential diagnosis of other soft‐tissue tumors.