Metastatic PRAME-Expressing Juvenile Spitzoid Melanoma on the Buttock

Since the cost of molecular biological methods for Spitzoid neoplasms is expensive, the number of institutes that employ these methods might be limited. Preferentially expressed antigen in melanoma (PRAME) is a tumor-associated antigen that is useful to distinguish melanoma from other melanocytic disorders, including pediatric Spitzoid tumors that are difficult to diagnose by conventional methods alone. In this report, we report a case of PRAME-expressing juvenile Spitzoid melanoma with lymph node metastasis. Unexpectedly, there were few PRAME-expressing cells in the primary tumor, whereas most metastatic tumors expressed PRAME in the metastatic lymph node. These observations might suggest that, in Spitzoid melanomas, a limited number of melanoma cells possess metastatic potential and that metastatic lesions possess clonality.