Early View
CASE STUDY

Proliferative Neurocristic Hamartoma Arising From a Congenital Melanocytic Nevus: A Case Report

Aizlynn Anne J. Robledo

Aizlynn Anne J. Robledo

Department of Dermatology, MacKay Memorial Hospital, Taipei, Taiwan

Search for more papers by this author
Yu-Hung Wu

Corresponding Author

Yu-Hung Wu

Department of Dermatology, MacKay Memorial Hospital, Taipei, Taiwan

Department of Medicine, MacKay Medical University, New Taipei City, Taiwan

Correspondence:

Yu-Hung Wu ([email protected])

Search for more papers by this author
First published: 15 July 2025

Funding: The authors received no specific funding for this work.

ABSTRACT

Proliferative neurocristic hamartoma (PNH), a rare variant of proliferative nodule, is a benign cutaneous proliferation with melanocytic, neurosustentacular, and mesenchymal differentiation that develops within a congenital or acquired melanocytic nevus. We report the case of a 38-year-old female who presented with a brownish-black plaque on the right medial sole that appeared during childhood and showed rapid nodular growth in the center over the past year. Histological examination revealed a well-demarcated dermal nodule characterized by spindle cell proliferation in a haphazard pattern in the center, with a congenital melanocytic nevus in the periphery. Immunohistochemical staining for S-100, SOX-10, HMB45, EMA, Glut-A, and CD34 demonstrated melanocytic, perineural, and fibrous differentiation in the central nodule, consistent with PNH. The mitotic activity was very low for the Ki-67 stain, and the PRAME stain was negative. Accurate pathological diagnosis is essential to reassure the patient of the nature of this changing mole and exclude the possibility of melanoma.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

The full text of this article hosted at iucr.org is unavailable due to technical difficulties.