Merkel cell carcinoma: Spontaneous resolution and management of metastaticdisease

BACKGROUND. Merkel cell carcinoma (MCC) is a rare, aggressive, cutaneous ne oplasm. The primary form of initial treatment is wide surgical excision. Th e use of Mohs micrographic surgery as the primary form of treatment in MCC has been controversial. The course of MCC is often aggressive, with early m etastasis, widespread disease, and death. Despite the poor prognosis, spont aneous regression has occasionally been reported. OBJECTIVE. We describe the clinical course of two patients with Merkel cell carcinoma who underwent treatment with Mohs micrographic surgery for the p rimary MCC. Metastases were excised in the first case and spontaneously reg ressed in the second. Both patients are without clinical disease at the tim e of this report. METHODS. Histopathology, clinical records, and the current literature are r eviewed. RESULTS. One patients was without recurrence of MCC for 13 years of follow- up. The other patient experienced clinical spontaneous remission after noda l spread of the disease, with no recurrence for 18 months after clinical re mission and 24 months after surgery. CONCLUSION. The treatment of Merkel cell carcinoma with Mohs micrographic s urgery (MMS) has been successful for the control of primary skin disease, a nd is at least comparable to wide excision. Spontaneous regression may occu r in the course of this usually relentless and aggressive disease. The expl anation for spontaneous regression of MCC is unknown.