Eccrine porocarcinoma: epidemiologic and histopathologic characteristics.

Background: Porocarcinoma is a rare tumor, representing 0.005% of all malignant epithelial neoplasms. The majority of publications are single case reports. The objective of this study was to describe the epidemiologic and histopathologic characteristics of patients diagnosed with eccrine porocarcinoma.

Methods: A retrospective study was carried out from January 1994 to December 2010. Cases with a histopathological diagnosis of eccrine porocarcinoma were included. The investigated variables were frequency, gender, age, time of evolution, localization, morphology, referral clinical diagnosis, and histopathology patterns. The information was analyzed using descriptive statistics.

Results: During this 17-year period, 33 cases diagnosed with eccrine porocarcinoma were detected. Female gender was predominant with 64% cases. The average age was 74 ± 12 years. The most frequent location was the head with 37% cases; the most common observed morphology was nodular, in 46%. The main referral diagnosis was squamous cell carcinoma in 67% of cases. With regard to the histopathology characteristics, necrosis predominated in 64% cases, comedonecrosis in 45% cases, squamous differentiation in 42% cases, and melanocyte colonization in 21%.

Conclusions: Our series presents some clinical and histopathology differences with previously reported, such as the most frequent localization in the head and the presence of melanocyte colonization.