The authors have indicated no significant interest with commercial supporters. E ccrine porocarcinoma is a rare malignant sweat gland tumor. Pinkus and Mehregan first described it in 1963 1 as an epidermotropic eccrine carcinoma, and Mishima and Morioka introduced the term eccrine porocarcinoma in 1969. 2 Approximately 20% of cases metastatize to regional lymph nodes and, more rarely, visceral metastases can occur. Robson and colleagues 3 have defined some prognostic factors in primary localized porocarcinoma.We report a case of eccrine porocarcinoma and its clinical course after local therapy and analyze prognostic factors. Case ReportA 78-year-old man was referred to the Medical Oncology Service of University Hospital, Ramó n y Cajal, Madrid, Spain, with a diagnosis of malignant poroma in the left proximal extremity.In January 2004, he consulted for an erythematous verrucous plaque on the back of his left thigh that persisted after three cryotherapy treatments. An excision of the lesion was performed in February 2004.The histopathologic examination showed, at scanning magnification, an asymmetric neoplasm (Figure 1) with poor circumscription and marked variation in size and shape of neoplastic cells. The tumor had an intraepidermal and an invasive intradermal component with an infiltrative growth pattern that involved the resection margin. Higher magnification revealed poroid and cuticular neoplastic cells with nuclear and citoplasmic pleomorphism, nuclear hyperchromatism, and mitotic activity (15 mitoses per 10 high-power fields). They showed ductal differentiation and intracitoplasmic lumen formation (Figure 2). The tumor depth was 2.20 mm, and it showed lymphovascular invasion.A second surgery was performed with expanded margins. The histology report revealed a porocarcinoma infiltrating to the dermoepidermal limit without involving surgical margins.In October 2005, the patient presented with left inguinal lymph nodes that had been increasing for 2 months. A fine-needle aspiration was performed with a diagnosis of metastases from malignant poroma. A computed tomography (CT) body scan showed a conglomerate of left inguinal lymph nodes of approximately 3 cm in diameter. A left iliac-inguinal lymphadenectomy was performed, and the pathologic study revealed metastases in one of eight inguinal nodes and three of five external iliac nodes.The patient was referred to the department of medical oncology. A CT body scan was performed that did not show any evidence of systemic disease.

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