Pigmented epithelioid melanocytoma (animal-type melanoma): An institutional experience

Publication date: August 2017
Source:Journal of the American Academy of Dermatology, Volume 77, Issue 2
Author(s): Michael J. Bax, Marc D. Brown, Paul G. Rothberg, Todd S. Laughlin, Glynis A. Scott
BackgroundPigmented epithelioid melanocytoma (PEM) is an uncommon, recently described entity with unknown biologic behavior. There is a high rate of regional metastases, but limited evidence of distant metastases or disease-related death.ObjectiveWe sought to report our series of patients given a diagnosis of PEM at our institution and provide mutational analysis of genes commonly implicated in melanoma in 2 cases.MethodsThe pathology database was queried for cases of PEM diagnosed at the University of Rochester. Charts were reviewed for follow-up information. Mutational analysis of melanoma-associated genes was performed on 2 cases.ResultsNine cases of PEM were retrieved in a 10-year retrospective review. Five patients underwent sentinel lymph node biopsy with 3 of 5 having a positive sentinel lymph node. All 9 patients are alive and disease-free with average follow-up of 38.75 months. Two tumors were tested for common melanoma-associated mutations, and were negative, except for a telomerase reverse transcriptase promoter deletion detected in 1 sample. The deletion has not been associated with melanoma, and therefore its biologic significance is unclear.LimitationsSmall sample size, retrospective nature, and single institution experience are limitations.ConclusionsPEM appears to have an indolent behavior. However, currently the evidence is too limited to provide insight into its true biologic potential.



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