Histopathological and Molecular Features of a Conjunctival Caruncular Deep Penetrating Nevus

Abstract

We describe the first presentation of a deep penetrating nevus (DPN) on the lacrimal caruncle. This lesion was seen in an 18-year-old woman presenting with hemorrhage of a long-standing pigmented mass on the caruncle. Histology showed a combined melanocytic neoplasm that consisted of two different melanocytic components. The differential diagnosis, based on histological examination, was a conventional melanocytic nevus, a Spitz nevus, or a combined melanocytic nevus. On the molecular level, one of the components revealed a mutation in the CTNNB1 gene encoding the β-catenin protein, while both components harbored a BRAF V600E mutation, without molecular features of a malignant melanocytic lesion. This presentation of a DPN of the lacrimal caruncle emphasizes the similarities of the caruncle with the skin.