The first reported case of ectopic breast tissue of the vulva was reported by Hartung in 1872 when he described a fully formed breast in the left labia majora [4
]. The cases that followed this initial description were of varying degrees of anatomical development and functionality of which only a few have been histologically confirmed cases of primary breast adenocarcinoma of the vulva. This is an exceedingly rare carcinoma presentation and only a handful of case studies exist as evidence on which to base clinical management. To date 25 cases have been reported involving vulva infiltrating carcinoma [3
]. As was the case with our patient, this cohort classically presents with a history of an innocuous lesion in the vulva area that was noted in their premenopausal years [1
]. The lesion has no typical characteristics and does not cause pain, so it may go ignored for years. The only way to determine pathological significance of the lesion is via biopsy with required immunohistochemistry to determine the tumor type and prognosis. For diagnostics purposes, antibodies associated with breast carcinoma include estrogen receptor (ER), progesterone receptor (PR), gross cystic fluid protein (GCDFP), HER-2/neu, cytokeratins (CK5/6, CK7, CK20), and the mucin glycoprotein antibodies, namely, MUC2, MUC3, MUC5AC, MUC6, and DAS-1. Of this group, estrogen, progesterone, and GCDFP are exceptionally specific for breast carcinoma. The literature would suggest that these tumors, aside from their unique location, act strictly as an equivalent breast mass would in regards to hormonal responsiveness and aggressiveness [1
]. Therefore, appropriate management of such lesions mirrors the evidence-based management protocols in place for breast cancer.
The majority of case reports in the literature detail management involving a wide local excision or radical vulvectomy with node dissection followed by adjuvant chemotherapy, hormonal therapy, or radiation, echoing the management of an isolated malignant breast mass. Further tailored therapy depends on histological tumor type as was the case with our patient. At present, patients with ER positive vulva cancer have been offered Tamoxifen as an adjuvant hormonal therapy given that it has been proven to increase survival in patients with ER positive breast malignancies. One study from the UK discussed the use of Anastrozole on an 81-year-old female with primary lobular breast cancer of the vulva given that it is at least as effective as Tamoxifen in postmenopausal women [5
]. Unfortunately, this case report did not give further details as to the patient's outcome, and a case report would not suffice as appropriate evidence to adopt this practice in place of Tamoxifen.
In 2006, Abbott and Ahmed [6
] of Mayo Clinic Department of Dermatology reviewed 19 cases reported in the literature and described a 51-year-old patient with a long-standing nodule on her right interlabial sulcus. Excisional biopsy and Mohs micrographic surgery demonstrated an infiltrating adenocarcinoma of the mammary-like glands involving the dermis [6
This review of 20 cases found that the mean age at diagnosis was 59.6 years, the labia majora were involved in 13 cases (65%), and the mean lesional size was 2.5
]. In keeping with our literature search, they reported that tumor histologic patterns varied significantly and the criteria for establishing the diagnosis of adenocarcinoma of mammary-like glands included identifying transition zones between normal mammary-like glands and adenocarcinomatous areas. Abbott and Ahmed [6
] concluded that aggressive surgical therapeutic regimens, particularly in the case of tumors localized to the skin, should be reassessed, given the morbidity faced by such therapy. Rather, they argued for Mohs micrographic surgery suggesting that alternate management may be adopted for tumors localized to the skin, especially in elderly patients [6
]. This tumor localization to the skin is unique to ectopic breast carcinoma given that cancer of the breast itself is not characterized as such if localized to skin only.