POROCARCINOMA DETECTED BY FINE-NEEDLE ASPIRATION BIOPSY OF A NODE METASTASIS - A CASE-REPORT

BACKGROUND: Porocarcinomas were first reported by Pinkus and Meherenga n in 1963 as uncommon malignant adnexal tumors of the skin characteriz ed by epi dermotropism with pagetoid diffusion within the epidermis. C ASE: The cytologic findings of an eccrine porocarcinoma lymph node met astasis in a 65-year-old female and histologic features of the skin re currence are reported. Metastasis was firstly identified by fine needl e aspiration biopsy (FNAB) performed on one inguinal lymph node. Cytol ogically the tumor was characterized by atypical malignant cells showi ng clear granular or keratinized cytoplasm and vesicular nuclei, with prominent nucleoli, which were irregularly dispersed or forming nests or cords, sometimes harboring central necrosis. The skin metastasis, d etected after the cytologic FNAB diagnosis, showed superficial dissemi nation within the epidermis and dermal invasion. CONCLUSION: Cytologic diagnosis of porocarcinoma metastases by FNAB is important for adequa te treatment, but adherence to strict diagnostic criteria is necessary . The tumor cells could be histogenetically related to the intraepider mal duct cells of the eccrine sweat glands, and pagetoid diffusion is considered a sort of homing phenomenon.