Clinicopathologic correlations of cutaneous neuroendocrine Merkel cell carcinoma.

A study of 50 consecutive cases (22 men, 28 women; age range, 39 to 84 years; mean age, 65 years) of cutaneous neuroendocrine Merkel cell carcinoma (CNC), 39 of whom had a mean follow-up of 34 months, revealed that the prognostic significance of the histopathologic subtyping in trabecular, solid, and diffuse variants of CNC was not as important as the pathologic postsurgical staging in localized, regional, and extraregional disease. The overall mortality was 23.5%. None of the 19 patients with localized disease died of CNC, while 11% of the 24 patients with regional disease and all seven patients with extraregional disease at presentation died of CNC. A second primary malignancy was found to be associated with the CNC in 15% of the cases. The clinical course in patients with localized disease was favorable in spite of the high number of local recurrences. Also, the presence of regional metastases was not related to an unfavorable prognosis. In 68% of the cases the disease involved the lower limbs or girdle. In ten cases the overt exophytic presentation of primary CNC was replaced by the presence of tumor masses infiltrating the inguinal soft tissues with or without nodal involvement.