An Atypical Deep Penetrating Nevus With Mutations in Beta Catenin, BRAFV600E, and IDH1R132C in an 8-Year-Old Boy. (6th August 2022)

• Record Type: Journal Article
• Authors: Ireland, Amanda M.; Wood, Benjamin A.; Whitfield, Joseph; Amanuel, Benhur; Harvey, Nathan T.; Mesbah Ardakani, Nima
• Is Part Of: American journal of dermatopathology. Volume 44:Number 8(2022)
• Page Start: 607
• Page End: 610
• Publication Date: 2022-08-06
• Subjects: deep penetrating nevus -- IDH1 R132c -- BRAF V600E -- child -- dermatopathology; Skin -- Diseases -- Periodicals; Histology, Pathological -- Periodicals; 616.50705
• DOI: 10.1097/DAD.0000000000002198
• Languages: English
• ISSNs: 0193-1091

Abstract

Abstract: Deep penetrating nevus (DPN) is a pigmented melanocytic tumor which typically displays a wedge-shaped deep penetrating architecture. Some cases show a coexisting component resembling conventional melanocytic nevus. These morphological attributes are correlated with the acquisition of genomic alterations in the Wnt pathway on a background of underlying activating MAPK pathway mutations. Lesions with features of DPN, but displaying expansile architecture, sheet-like arrangement of cells, cytological atypia, and/or more than rare mitotic activity have been described as "atypical deep penetrating nevus" or "deep penetrating melanocytoma." The molecular correlates of these atypical morphological features are not well-established. In this case report, we describe a tumor in an 8-year-old boy with histological features of atypical DPN showing somatic BRAF V600E, beta catenin, and IDH1 R132C mutations. The combination of abnormalities in MAPK and Wnt pathways with IDH1 mutations seems to be a reproducible feature in a subset of atypical DPNs. Whether this "three-hit" combination is associated with a significant risk of adverse outcome remains to be established.