Primary Extra Mammary Paget's Disease of Vulva, With Apocrine Adenocarcinoma, Signet Ring Cell Differentiation and Distant Metastasis.

Extramammary Paget's disease (EMPD) with invasive carcinoma and distant metastasis is extremely rare. In vulva EMPD associated apocrine carcinoma with signet ring cell differentiation has not been described in the literature so far. Its slow evolution, varied clinical presentation and histological appearances, lead to difficulty in diagnosis of this disease. We hereby report a case of primary EMPD with invasive carcinoma and distant metastasis in a 59-year-old female who presented with erythematous indurated plaque over vulva. Histopathology revealed Paget cell infiltration throughout the epidermis with invasive carcinoma in dermis and liver metastasis on CECT. The immunohistochemical expressions of CK7, CK20, GCDFP-15, CEA, p40, CDX 2, Her-2/ neu, AR, ER, were examined to explicate the cellular differentiation of this carcinoma. According to the histological assessment, this case was diagnosed as primary EMPD with apocrine adenocarcinoma, signet ring cell differentiation, vulva. Owing to poor prognosis, a high index of clinical suspicion along with histological and immunohistochemical assessment is of utmost importance in arriving at final diagnosis.