Superficial Wnt-Activated Melanocytic Nevi/Melanocytomas With a Junctional Component: A Case Series.

Autor:	Ng S; Department of Pathology & Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY., Hall KC; Department of Pathology & Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY., Busam KJ; Department of Pathology & Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY., Lezcano C; Department of Pathology & Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY., Moy AP; Department of Pathology & Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY., Pulitzer M; Department of Pathology & Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY., Sriharan A; Department of Pathology & Laboratory Medicine, Dartmouth Hitchcock Medical Center, Lebanon, NH; and.; Geisel School of Medicine at Dartmouth, Hanover, NH., Yan S; Department of Pathology & Laboratory Medicine, Dartmouth Hitchcock Medical Center, Lebanon, NH; and.; Geisel School of Medicine at Dartmouth, Hanover, NH., Linos K; Department of Pathology & Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY.
Jazyk:	angličtina
Zdroj:	The American Journal of dermatopathology [Am J Dermatopathol] 2024 Oct 01; Vol. 46 (10), pp. 648-652. Date of Electronic Publication: 2024 Aug 14.
DOI:	10.1097/DAD.0000000000002804
Abstrakt:	Abstract: The conventional morphological characteristics of Wnt-activated deep penetrating/plexiform melanocytomas/nevi (DPN) are those of large spindled or epithelioid melanocytes with distinctive voluminous amphophilic cytoplasm, fine pigmented granules, and surrounding melanophages. The central molecular hallmark is the activation of the Wnt-pathway predominantly driven by mutations in the beta-catenin ( CTNNB1 ) gene. Although typically lacking a junctional component, a lesser-known superficial variant with a junctional component has been identified, which could potentially lead to diagnostic challenges. This study presents a cohort of 11 such cases displaying a junctional component of DPN from 10 patients (5 women and 5 men; age range: 27-78 years; median age: 51 years). The nevi were distributed as follows: 1 conjunctival, 1 scalp, 2 lower limb, and 6 truncal lesions. Eight cases were combined with a conventional nevus, 2 cases displayed pure DPN cytology exhibiting only a junctional element, and 9 cases exhibited some degree of lentiginous architecture. All cases demonstrated a low mitotic index (<1 mitosis/mm 2 ). Immunohistochemistry revealed positive BRAF V600E staining in 8 cases (8/11), whereas all cases tested (11/11) were PRAME negative. Nuclear beta-catenin and LEF1 staining was consistently strong and diffuse with DPN cytology (11/11), along with robust cyclin D1 staining in all cases tested (11/11). By contrast, all 9 conventional nevi showed an absence of nuclear beta-catenin staining (0/9) and weaker, mosaic-type LEF1 and cyclin D1 staining was observed. This study emphasizes the diagnostic challenge these nevi can pose in the absence of a conventional, deeper DPN component, which can potentially be misdiagnosed as melanoma. Competing Interests: The authors declare no conflicts of interest. (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)
Databáze:	MEDLINE
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