A 50-year-old woman comes to the office for evaluation of a mole on her back. The mole has been present for several years, but her daughter is concerned that it might have grown larger lately. The patient has no other medical conditions but had frequent sunburns during childhood. Dermoscopic examination of the lesion is shown in the image below. The lesion has multiple color variations, including dark brown, pink, red, and whitish areas. Excisional biopsy of the lesion is performed. The whitish areas (arrows) seen on histologic examination most likely represent which of the following underlying processes?

Question

A 50-year-old woman comes to the office for evaluation of a mole on her back.  The mole has been present for several years, but her daughter is concerned that it might have grown larger lately.  The patient has no other medical conditions but had frequent sunburns during childhood.  Dermoscopic examination of the lesion is shown in the image below.  The lesion has multiple color variations, including dark brown, pink, red, and whitish areas.  Excisional biopsy of the lesion is performed.  The whitish areas (arrows) seen on histologic examination most likely represent which of the following underlying processes?

Quizplus · Accepted Answer

This patient who had multiple sunburns as a child has a skin lesion with several classic features of melanoma, including Asymmetry, Border irregularity, Color variegation, Diameter ≥6 mm (hash marks), and Evolution over time. Color variegation is a common feature of melanoma; the different colors represent different areas of activity within the tumor: Melanocyte regression is also a hallmark of treatment response to melanoma immunotherapies, such as the programmed cell death receptor-1 (PD-1) inhibitor pembrolizumab. (Choice D) This patient's skin findings are characteristic of malignant melanoma. Proliferating nonneoplastic melanocytes do not generally play a role in the development or progression of melanoma. Educational objective: Melanoma lesions often have multiple color variations. The different colors represent different activities within the tumor. Whitish/gray areas occur when cytotoxic T cells recognize tumor antigens and destroy malignant cells, leading to melanocyte regression. Red areas arise due to vessel ectasia and local inflammation, whereas brown or black areas are generally due to advancing malignant melanocytes.

A 50-Year-Old Woman Comes to the Office for Evaluation of a Mole