Eccrine porocarcinoma with extensive cutaneous metastases.

BACKGROUND: Eccrine porocarcinoma (EPC) is an uncommon malignant neoplasm that originates in the intraepidermal portion of the eccrine sweat duct. Although porocarcinoma is a slow-growing tumor, up to 20% of cases can metastasize to regional lymph nodes, thus increasing mortality. METHODS: We describe the clinical and histopathological features and clinical course of three cases of extensive metastatic EPC diagnosed in our department over the last 10 years. RESULTS: All three patients were women aged 89-96 years. They had numerous skin tumors on the left leg that were histologically and immunohistochemically diagnosed as metastatic EPC. Only one patient had a history of primary porocarcinoma, which had been excised 6 years earlier. The remaining two patients had a previous lesion diagnosed as squamous cell carcinoma. We treated the patients with palliative radiotherapy and/or chemotherapy. Only one patient is currently alive. CONCLUSIONS: The cases of cutaneous and regional metastatic EPC we present occurred in elderly women with major involvement of the left leg. The third case is noteworthy, as the patient presented a long latency period before metastases appeared. Difficulties in the clinical diagnosis--and occasionally histological diagnosis--of primary EPC could delay more aggressive treatment, although optimal treatment does not always guarantee a good prognosis.