Axillary Paget's disease associated with breast carcinoma in an elderly patient

ARTICLE

Auteur(s) : Ana OLIVEIRA anacsoliveira@gmail.com, Madalena SANCHES, Manuela SELORES

Dermatology Department, Hospital de Santo António–Centro Hospitalar do Porto, Edifício ex-CICAP, Rua D. Manuel II s/n°, 4000-Porto, Portugal

Extramammary Paget's disease (EMPD) is an uncommon intraepithelial adenocarcinoma, accounting for 6.5% of all cases of Paget's disease [1]. It affects primarily the genital and perianal regions. Axillary Paget's disease is very rare [2] and even rarer is its relation with breast adenocarcinoma [3]. We report axillary EMPD in a male patient with breast carcinoma.

A 82-year-old man presented with an axillary lesion present for almost 4 years. He had been treated with topical corticosteroids and antifungals without success. There was no personal history of immunosuppression or exposure to chemicals or radiation predisposing to carcinogenesis and no family history of skin cancer. On physical examination an erythematous, well-defined plaque with eroded areas was noted on the right axilla (figure 1A). There were no adenomegalies and the breast examination, including the nipples, was unremarkable. No nipple discharge was noted.

The skin biopsy revealed large, intraepidermal, atypical, pale-staining, non-keratinizing neoplastic cells (figure 1B) and intraductal carcinoma-like structures (figure 1C). These cells stained positive for keratin AE1/AE3, keratin 20 (figure 1D) and CAM 5.2 (figure 1E) and negative for keratin 7. These findings led to the diagnosis of EMPD. Based on these findings we raised the hypothesis of a secondary EMPD. The patient underwent an MRI which revealed, on the right breast, a pericentimetric, spiculated nodule with hypersignal on T2 (figure 1F) and uptake of intravenous contrast, suggestive of malignancy. The biopsy confirmed the diagnosis of breast adenocarcinoma. The patient was referred to the Surgery Department and a total mastectomy with lymph node resection followed by adjuvant chemotherapy and radiation therapy was performed. He is in his 7^th month of follow-up with no evidence of recurrence.

Extramammary Paget's disease is a rare neoplastic disease in which there is intraepithelial infiltration by neoplastic cells showing glandular differentiation [4]. There is some controversy regarding its etiopathogenesis. The current theory is that, unlike mammary Paget's disease, EMPD arises as a primary intraepidermal neoplasm in most cases, explaining the much smaller proportion of cases in which EMPD is caused by extension of an underlying malignancy [4].

Axillary Paget's disease is very rare, with few cases reported in the literature [2]. Clinically it presents as well-defined erythematous plaques, mostly arising in areas rich in apocrine glands [5]. The diagnosis is made by skin biopsy demonstrating a thickened epidermis with large cells with abundant fine granular cytoplasm and a large centrally situated nucleus with nuclear atypia [2]. Immunohistochemistry may be helpful in distinguishing primary intradermal Paget's disease from that associated with internal adenocarcinoma [2]. Most cases are keratin-7 positive (K-7), but the few cases which do not label with this antibody are commonly associated with an underlying malignancy [2]. In contrast to K-7, keratin 20 (K-20) is found more frequently in cases of secondary EMPD [4]. In fact, in our patient, we could confirm this theory, as K-7 was positive and K-20, was negative. The immunohistochemistry of the breast nodule revealed K-7 and K-20 negative staining, in accordance to the corresponding EMPD. We could relate them based on these findings. Immunostains for GCDFP-15 and Her2/neu were not performed. We expected positive EMPD and breast stains for GCDFP-15, as it is a marker of apocrine epithelium. Her2/neu is detected in 44% of cases of ductal carcinoma and, in these cases, the immunostains should also be positive for the extramammary Paget's lesions as an extension of the breast ductal carcinoma [4].

Treatment relies on wide surgical excision as invasion of the epidermis by Paget cells often largely exceeds the visible limits of the lesion [1]. A clinical follow-up is recommended considering the high risk of recurrences [1].

Disclosure

Financial support: none. Conflict of interest: none.

References

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