Pseudomamma on the foot: An unusual presentation of supernumerary breast tissue
1. Department of Gynecology and Obstetrics, Hospital Estadual Sumaré, Universidade Estadual de Campinas. email@example.com
A 22-year-old woman sought medical care for a lesion in the plantar region of her left foot, a well-formed nipple surrounded by areola and hair. Microscopic examination of the dermis showed hair follicles, eccrine glands, and sebaceous glands. Fat tissue was noted at the base of the lesion. Clinical and histopathologic findings were consistent with the diagnosis of supernumerary breast tissue, also known as pseudomamma. To our knowledge, this is the first report of supernumerary breast tissue on the foot.
A 22-year-old woman sought medical care due to a lesion in the plantar region of her left foot present since birth. She had no complaints of pain, pruritus, or alterations in volume or color. During her pregnancy or postpartum period, there had been no change in the lesion. Family history for similar conditions was negative.
The woman had the following gynecological and obstetric history: menarche and thelarche beginning at the age of 12; gravida 1, para 1; birth of her first child at the age of 20.
On physical examination, the breasts were symmetrical having no nodes or retractions. In the plantar region of the patient's left foot, there was a well-formed nipple was surrounded by areola and hair on the surface, measuring 4.0 cm in diameter, with no palpable nodes (Figs. 1 and 2). The remaining physical examination was normal, including the mammary line. Results of the following laboratory tests were normal: complete blood count, fasting serum glucose level, urine exam, electrolytes, serum urea and creatinine. No alterations were found during ultrasound of the lesion and urinary tract.
The patient underwent an incisional biopsy of the lesion. Histologic findings were squamous epithelium with hyperkeratosis, epithelial hyperplasia without atypia, epithelial cytoplasmic vacuolation, and hyperpigmentation of the epidermal basal membrane. In the dermis there were hair follicles, eccrine glands, and sebaceous glands. Fibrosis and fat tissue were noted at the base of the lesion. No glandular tissue was identified.
Anomalies associated with breast development are not uncommon. Supernumerary nipples, and less frequently supernumerary breasts, are present in about 1-5 percent of the population . Such alterations are more common in women, usually occurring along the embryonic milk line, which extends from the axilla to the groin [1, 2].
Supernumerary breast tissue (SBT) is rarely found beyond the mammary line. However, the back , shoulder , face , and thigh  have been described as sites of SBT development. When glandular tissue is present, SBT may be affected by the same disease processes that occur in normally positioned breast tissue [7, 8, 9]. To our knowledge, this is the first report of SBT on the foot.
The classification established by Kajava  is based on the presence or absence of nipple, areola and breast glandular tissue, and is divided into eight categories:
The current case reported is included in the fifth category, i.e., presence of nipple and areola but no glandular tissue. Polythelia and pseudomamma are the two most common forms of SBT .
The study of SBT merits special attention because of some aspects. Initially, the patient seeks medical care for cosmetic reasons, expressing desire to have the lesion surgically removed, particularly if it is located in a visible area . The presence of glandular tissue in the lesion should be investigated, because SBT is not exempt from the same diseases and physiologic processes that can affect normally positioned breasts, including the cyclical alterations induced by hormone action [2, 9]. Usually, the presence of glandular tissue is suggested after the onset of puberty, first childbirth, or lactation, at times when a woman may complain of an increase in size, pain and discomfort, as well as milk secretion . In the current case, the patient was asymptomatic, even after pregnancy, suggesting a lack of glandular tissue. However, despite the clinical picture, it was necessary to perform a histologic examination to rule out the presence of glandular tissue.
Another aspect that should be kept in mind is the association between SBT and renal malformations [12, 13, 14]. Some authors describe a close association between both conditions, reporting that patients with SBT should be investigated for the presence of urinary tract malformations . However, other authors found no evidence to support such an association, suggesting that routine investigation for renal anomalies is not indicated in patients with supernumerary nipple . In the present case, ultrasonography of the urinary tract identified no malformations. In fact, there is still uncertainty as to the best approach in these patients.
Apart from renal anomalies, other organ system anomalies have been described in association with SBT, including abnormalities of the cardiovascular and gastrointestinal systems, as well as hematologic disorders [12, 16, 17]. The limited number of cases makes it difficult to establish these relationships in a clear and definite manner.
Despite the difficulties in establishing relationships between SBT and other diseases, the identification of SBT should draw the attention of the physician to these possible associations and to the occurrence of malignancy, when breast glandular tissue is present. In cases in which it is clinically impossible to rule out the presence of breast glandular tissue, we believe that a histologic examination of the lesion is required.
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