Highlighting the immunohistochemical profile of melanocytomas: review

The histological assessment of atypical melanocytic neoplasms is mandatory to ensure proper diagnosis and treatment. However, for some atypical lesions, expert pathologists report only moderate concordance in the diagnosis. In addition, certain atypical neoplasms have been coined differently in the literature. These designations include among others atypical and metastasizing Spitz tumor, malignant Spitz naevus, borderline and intermediate melanocytic tumor, and melanocytic tumor of uncertain malignant potential (MELTUMP) or Spitzoid melanocytic tumor of uncertain malignant potential (STUMP). These neoplasms are grouped here under the heading melanocytoma. Such melanocytic lesions have a benign outcome but exhibit an atypical and worrisome aspect. Rare individual cases of melanocytomas can progress to locoregional disease (agminate melanocytomas), and even beyond. At times, the distinction between melanocytoma and melanoma is difficult and may even be impossible. However, multipronged immunohistochemistry can help define malignancy risk stratification and therapeutic guidelines.