Primary dermal melanoma (PDM) is a subtype of melanoma confined to the dermis that may be morphologically impossible to distinguish from cutaneous metastatic melanoma (CMM).
We sought to better characterize PDM by describing the clinical, histologic, and molecular features of 49 cases of PDM and determine whether a gene expression–profiling test could help distinguish PDM from CMM.
We describe 49 cases of PDM and determined whether any clinical or histopathologic features had a statistically significant relationship with outcome. Secondly, we performed a melanoma gene expression–profiling test on a subset of the PDM and CMM cases.
Overall recurrence was infrequent and seen in 9 of 49 cases. Six patients had locoregional recurrences and 3 patients had distant metastasis. None of the clinical or histologic parameters showed a statistically significant relationship with recurrence. There was a statistically significant association of a class I signature by DecisionDx-Melanoma assay (Castle Biosciences Inc, Friendswood, TX) for PDM whereas CMM were more frequently class II (P value = .023).
The mean follow-up time was 26 months.
Most conventional staging parameters used for prognosis in cutaneous melanoma have limited applicability to PDM. The melanoma prognostic assay may be a useful tool for distinguishing PDM from CMM.Le texte complet de cet article est disponible en PDF.
Key words : American Joint Committee on Cancer, cutaneous metastatic melanoma, fluorescence in situ hybridization, gene expression profile, melanoma, primary dermal melanoma
Abbreviations used : CGH, CMM, FISH, GEP, IDN, IHC, NOS, PDM, SLNB
| Supported by the Irene D. Pritzker Foundation and partially supported by Castle Biosciences Inc.
| Disclosure: Dr Gerami has served as a consultant to Castle Biosciences Inc, Myriad Genetics, and DermTech Inc, receiving honoraria. Dr Guitart has served as a consultant to Castle Biosciences Inc, receiving honoraria. The other authors declared no conflicts of interest.
| Dr Sidiropoulos and Ms Obregon contributed equally to this article.