Metastatic melanoma with spontaneous complete regression of a thick primary lesion

Fig 1. Left side of the chest skin biopsy for primary malignant melanoma. Histopathologic examination found a thick primary melanoma characterized by atypical pigmented epithelioid cells with extensive ulceration. INTRODUCTION Spontaneous regression of malignant melanoma is defined by the disappearance of melanocytic neoplastic cells partially or completely. In contrast to the partial form, complete spontaneous regression of primary malignant melanoma is a rare-occurring phenomenon, with 76 cases reported in the literature since 1866. The criteria for the diagnosis of regression were established by Smith and Stehlin and modified later. Overall, the impact of partial or complete regression on prognosis is anecdotal and controversial; however, we report a case with complete regression of a histologically diagnosed thick primary malignant melanoma with rapid development of metastatic disease and death. (Hematoxylin-eosin stain; original magnification: 3100.)