Melanocytic tumors with intraepidermal melanophages: a report of five cases with review of 231 archived cutaneous melanocytic tumors

Abstract

Dermal melanophages are frequently encountered in both benign melanocytic nevi and malignant melanoma. In contrast, intraepidermal melanophages (IEM) are under-recognized in melanocytic lesions and their biologic significance is not understood. Herein, we report the clinical and histopathologic features of five melanocytic lesions featuring IEM encountered prospectively in our dermatopathology practice at the University of Chicago. Two hundred and thirty-one (231) archived skin primary melanocytic proliferations were also investigated retrospectively in a de-identified, archival teaching set collection. Nineteen of 231 of the archived cases were positive for IEM. Among the total 24 IEM-positive cases (5 prospective and 19 archived cases), 13 were categorized as Spitz nevi (p < 0.0001) and 3 as atypical Spitz tumors (p = 0.0152). Fourteen of 24 cases with IEM also exhibited intracorneal melanocytes (p < 0.0001). IEM are evidently not rare, especially in spitzoid melanocytic neoplasms. IEM in our series were significantly correlated with intracorneal melanocytosis, possibly indicating an association between IEM and suprabasal melanocytosis and/or transepidermal elimination of melanocytes.

Melanin accumulation in dermal stem cells deteriorates their exosome‐mediated skin basement membrane construction in solar lentigo

“…On the contrary, melanin pigment has also been found in dermal tissue of SL lesions, and it has been reported that the majority of melanin pigment in the dermis is localized on CD163 and FXIIIa positive macrophages 12,13 . These melanin‐phagocytosing macrophages are termed melanophages and are also known to be frequently present in benign melanocytic nevi and malignant melanomas, 14 but detailed studies have not been conducted. Recent in vitro studies have reported the phenomenon of melanin uptake by dermal fibroblasts, 15 raising the possibility that cells other than macrophages may be taking up melanin in the dermis of SL lesions.…”