Genetic analyses of a secondary poroma and trichoblastoma in a HRAS‐mutated sebaceous nevus

A sebaceous nevus is a congenital skin hamartoma caused by postzygotic HRAS or KRAS mosaic mutations. With age, affected individuals may develop secondary tumors within a sebaceous nevus. RAS mutations are harbored from the onset of sebaceous nevus, and further mutations can be expected to be requir...

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Bibliographic Details
Published in:Journal of dermatology 2021-08, Vol.48 (8), p.1268-1272
Main Authors: Minowa, Tomoyuki, Kamiya, Takafumi, Hida, Tokimasa, Okura, Masae, Kato, Junji, Idogawa, Masashi, Tange, Shoichiro, Hirano, Tomomi, Tokino, Takashi, Uhara, Hisashi
Format: Article
Language:English
Subjects:
Coexistence
Congenital diseases
Genetic analysis
HRAS gene
Mutation
Neoplasia
Nevus
NOTCH2
p53 Protein
poroma
sebaceous nevus of Jadassohn
Skin cancer
TP53
Tumors
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Summary:A sebaceous nevus is a congenital skin hamartoma caused by postzygotic HRAS or KRAS mosaic mutations. With age, affected individuals may develop secondary tumors within a sebaceous nevus. RAS mutations are harbored from the onset of sebaceous nevus, and further mutations can be expected to be required in order to explain the initiation of secondary tumors. However, genetic analyses of the secondary tumors have not been conducted. Herein, we describe the rare coexistence of a poroma and a trichoblastoma arising in a sebaceous nevus. This is the first report of an investigation of multiple genes in a secondary tumor in an SN. First, HRAS c.37G>C, which is the common mutation in sebaceous nevus, was detected in all three lesions (sebaceous nevus, poroma, and trichoblastoma). Next, to elucidate the potential second‐hit mutations in the secondary poroma and trichoblastoma, we applied a panel sequencing for skin cancers that was newly developed in our institution. Our comparison of the mutational profile of 95 skin cancer‐related genes in each of the three lesions newly revealed TP53 p.R158P in the poroma and NOTCH2 p.G329S in the trichoblastoma. TP53 p.R158P has been determined as a pathogenic mutation in other tumors, and NOTCH2 p.G329S was a novel mutation. We identified two novel mutations that may have contributed to the pathogenesis of the secondary tumor’s development. The roles of the mutations remain unclear.
ISSN:0385-2407
1346-8138
DOI:10.1111/1346-8138.15919