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Novel three‐way complex rearrangement of TRPM1‐PUM1 ‐ LCK in a case of agminated Spitz nevi arising in a giant congenital hyperpigmented macule
Author(s) -
Goto Keisuke,
Pissaloux Daniel,
Durand Luc,
Tirode Franck,
Guillot Bernard,
Fouchardière Arnaud
Publication year - 2020
Publication title -
pigment cell and melanoma research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.618
H-Index - 105
eISSN - 1755-148X
pISSN - 1755-1471
DOI - 10.1111/pcmr.12884
Subject(s) - hras , spitz nevus , pagetoid , nevus , neuroblastoma ras viral oncogene homolog , dermatology , pathology , melanocytic nevus , medicine , congenital melanocytic nevus , biology , melanoma , mutation , gene , cancer research , genetics , immunohistochemistry , kras
The genetic anomalies associated with the agminated variant of Spitz nevus have so far been limited to HRAS G13R mutations, especially when arising within a nevus spilus. A previous report exposed the case of a man with a giant pigmented macule involving his upper right limb and trunk. Since childhood, Spitz nevi have been periodically arising, within the pigmented area. The histopathology of several lesions displayed the usual criteria of junctional, compound, or intradermal Spitz nevi with a diversity of cytomorphological and architectural features. Some lesions spontaneously regressed. Genetic studies confirmed in three lesions an identical translocation involving TRPM1 , PUM1 , and LCK . No mutations in HRAS , NRAS , BRAF , or other known fusion genes linked to Spitz nevus were detected. LCK break‐apart fluorescence in situ hybridization confirmed the rearrangement was present not only in the melanocytic proliferation but also in the surrounding non‐spitzoid melanocytes. This report expands the list of genetic alterations involved both in giant congenital macules and in agminated Spitz nevi, and also extends the concept of mosaicism in melanocytes to gene translocations.