Management of Merkel cell carcinoma with emphasis on small primary tumors--a case series and review of the current literature.

A case series of Merkel cell carcinoma (MCC) is reported here and illustrates some of the current controversies in clinical management of this disease. From 1988-2007, 145 cases (74 men and 71 women) were analyzed. These were combined with other cases in the literature, hence the total number of patients was 433. Nodal metastases occurred clinically at presentation in 9/105 (9%) patients with primary tumor size <1 cm. The rate of nodal metastases is too high to obviate sentinel node biopsies even for these small tumors. For the 87 patients with intermediate tumor size (>1 - <2 cm), nodal metastases occurred clinically in 11 of 87 patients (13%) at presentation and 23 of 87 patients (26%) during follow-up. Distant metastases occurred in 20 of 87 patients (23%) only at follow-up. The risks of nodal and distant failures for tumors of intermediate sizes were sufficient to be classified as high-risk for clinical study purposes.