Brief ReportCombination of Congenital and Deep Penetrating Nevus by Acquisition of β-Catenin ActivationGarrido, Maria C MD, PhD*; Nájera, Laura MD, PhD†; Navarro, Antonia MD‡; Huerta, Victoria MD§; Garrido, Enrique MD*; Rodriguez-Peralto, Jose-Luis MD, PhD*; Requena, Luis MD, PhD¶Author Information *Department of Pathology, Hospital Universitario 12 de Octubre, Universidad Complutense, Instituto de Investigación I+12, Madrid, Spain; †Department of Pathology, Hospital Universitario Puerta de Hierro, Madrid, Spain; ‡Department of Pathology, Hospital Universitario Ramón y Cajal, Madrid, Spain; §Department of Pathology, Hospital Santa Caterina, Girona, Spain; and ¶Department of Dermatology, Fundación Jimenez-Diaz, Madrid, Spain. Correspondence: Maria C. Garrido, MD, PhD, Dpto de Anatomía Patológica, Hospital Universitario12 de Octubre, Avda de Córdoba s/n, 28041 Madrid, Spain (e-mail: [email protected]). The authors declare no conflicts of interest. The American Journal of Dermatopathology: December 2020 - Volume 42 - Issue 12 - p 948-952 doi: 10.1097/DAD.0000000000001704 Buy Metrics Abstract Deep penetrating nevus (DPN) is an intradermal, sometimes compound benign melanocytic lesion, which involves the reticular dermis, occasionally reaching the subcutis, which can raise concern for melanoma both clinically and histologically. Recently, it has been genetically defined by the combination of MAPK activating and β-catenin activating mutations. We sought to investigate genetic alterations in 2 cases of combined nevi of congenital melanocytic and DPN. Case 1 was a 16-year-old woman with a pigmented lesion on the trunk since birth, which was completely excised. Histopathological examination revealed a combined congenital nevus with a DPN. Comparative genomic hybridization showed no major genetic alterations, except for gain of 6q11.1 and point mutation of B-RAF V600E. Case 2 was a 62-year-old woman with a congenital pigmented lesion on the back. The lesion was diagnosed as a combined nevus of congenital and DPN. Comparative genomic hybridization showed no genetic alterations, and the NRAS Q61K was detected in both components. DPN is in most cases part of a combined nevus. Our cases showed strong and uniform nuclear expression of β-catenin and cyclin D1 in the DPN component suggesting the evolution of the congenital nevus to the DPN clone by acquiring β-catenin activating mutation. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.