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.