Unilateral Pigmented Extramammary Paget's Disease of the Axilla Associated with a Benign Mole: A Case Study and a Review of Literature

Abstract

Pigmented extramammary Paget's disease (PEMPD) is an uncommon intraepithelial adenocarcinoma and a rare variant of Paget's disease affecting skin that is rich in apocrine sweat glands such as the axilla, perianal region and vulva. It most commonly occurs in postmenopausal women and presents as a superficial pigmented scaly macule, mimicking a melanocytic lesion. The histological presentation is adenocarcinoma in situ with an increased number of melanocytes scattered between the Paget's cells. Therefore, PEMPD may be misdiagnosed as a melanocytic tumour both clinically and histologically. The tumour cells are usually positive for cytokeratin 7, epithelial membrane antigen, Cam 5.2, HER2, and mucicarmine stain while S100 and human melanoma black-45 highlight the processes of reactive dendritic cells. The association between Paget's cells and intratumoural reactive melanocytes is still unclear. We report our first case of PEMPD associated with an intradermal naevus involving the axilla in a 63-year-old woman.

Atypical cells on reflectance confocal microscopy may not represent melanoma: A case of axillary pigmented extramammary Paget disease

“…The true diagnosis of PEMPD was elucidated after immunohistochemistry (IHC) was performed for markers expressed in melanocytic and Paget cells. To our knowledge, this is the first case of PEMPD occurring in the axilla to be described on RCM, and the fifth reported case of axillary PEMPD in the English literature 5,6,8,14 . It is also the first case of PEMPD to be described explicitly in an African American patient.…”

“…Immunostaining for CK7-the most sensitive and specific marker for EMPD 3 , as well as CK8/18, helped to identify the round-oval single and nested cells as Paget cells. In other reported cases of PEMPD, Paget cells were most commonly positive for: CK7, 2,3,[5][6][7][8][9][10][11][12][13][14]16 carcinoembryonic antigen (CEA), 1,2,4,5,[10][11][12]14,16 cytokeratin CAM 5.2, 1,5,7,8,10,12,16 epithelial membrane antigen (EMA), 3,5,8,12,16 and gross cystic disease fluid protein 15 (GCDFP-15). [5][6][7]12 Dendritic melanocytes were generally positive for human melanoma black 45 (HMB-45), 1,2,4,5,[7][8][9]11,12 melanoma antigen/melanoma antigen recognized by T cells...…”

“…To our knowledge, this is the first case of PEMPD occurring in the axilla to be described on RCM, and the fifth reported case of axillary PEMPD in the English literature. 5,6,8,14 It is also the first case of PEMPD to be described explicitly in an African American patient.…”

“…PEMPD has been reported in men and women, of white and Asian races, with presentation in the fifth to ninth decades of life (average age 62). [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Lesions were primarily located in the genital area (vulva, scrotum, and perineum), and less commonly on the axilla, abdomen, and thigh. Most were clinically interpreted as other pigmented neoplasms, including seborrheic keratosis, atypical melanocytic nevus, and melanoma.…”

“…There are few well‐described cases of PEMPD in the literature to date, most of which highlight its diagnostic challenges. PEMPD has been reported in men and women, of white and Asian races, with presentation in the fifth to ninth decades of life (average age 62) 1‐14 . Lesions were primarily located in the genital area (vulva, scrotum, and perineum), and less commonly on the axilla, abdomen, and thigh.…”