Proliferating Cell Nuclear Antigen Staining in
Deep-Penetrating Nevi

Darius R. Mehregan, MD, David A. Mehregan, MD and Amir H. Mehregan, MD, Monroe, Michigan

Deep-penetrating nevus is a term proposed by Seab et al. to describe a distinctive benign melanocytic growth. The histologic differential diagnosis includes Spitz nevus, blue nevus, combined blue nevus and acquired melanocytic nevus, and malignant melanoma.

Clinically, the lesions often appear darkly pigmented. Clinicians may suspect either a blue nevus or a malignant melanoma and are often concerned about the extension of pigment into the subcutaneous fat at the time of excision.

Proliferating cell nuclear antigen (PCNA, cyclin) is a 36 kd marker of cellular proliferation that represents an accessory protein of DNA Delta-polymerase. The expression of PCNA is increased during the late G growth phase and peaks in the S phase of the cellular cycle. Recent studies have suggested that such markers of cellular proliferation may be useful in differentiating benign from malignant neoplasms or as prognostic markers in malignant neoplasms. Staining for PCNA has been reported in studies of squamous cell carcinoma, basal cell carcinoma, keratoacanthoma, and malignant melanoma. We have reviewed histologic sections of deep-penetrating nevi for the presence of PCNA and our results are reported.

JAAD 1995;33:685-7