Cutaneous Melanocytomas: Variants and Caveats

There is a regular improvement in the early clinical disclosure of various atypical melanocytic neoplasms (AMN). The histopathological examination of AMN remains mandatory for establishing their diagnosis and proper management. Panels of experts in AMN diagnosis report only moderate agreement in a diversity of puzzling cases. Some AMN have been differently designated in the literature including atypical Spitz tumor, metastasizing Spitz tumor, borderline and intermediate melanocytic tumor, malignant Spitz nevus and pigmented epithelioid melanocytoma or animal-type melanoma. Some acronyms have been further offered such as MELTUMP (after “melanocytic tumor of uncertain malignant potential”) and STUMP (after “Spitzoid melanocytic tumor of uncertain malignant potential”). In this review, such AMN at the exclusion of cutaneous malignant melanoma (MM) variants, are grouped under the tentative broad heading cutaneous melanocytoma. These lesions typically follow an indolent course, although they exhibit an atypical and sometimes worrisome patterns or cytologic aspects. Rare cases of cutaneous melanocytomas progress to locoregional clusters of lesions (agminate lesions), and even to regional lymph nodes. At times, the distinction between a cutaneous melanocytoma and MM remains problematic and even proves to be merely impossible. However, multipronged immunohistochemistry helps assessing the malignancy risk.