Hair Repigmentation as a Melanoma Warning Sign

The document discusses a rare phenomenon of localized hair repigmentation that may indicate underlying melanoma, as observed in an 85-year-old male patient. The patient presented with a localized darkening patch of hair on the scalp, under which an irregularly pigmented plaque measuring 5.0 cm in diameter was confirmed to be melanoma. The patient underwent a staged excision to remove the lesion. A PubMed search revealed 11 other reported cases of hair repigmentation associated with melanoma. The exact mechanism responsible for hair repigmentation in the setting of melanoma is unclear, but it may be caused by paracrine stimulation from melanoma cells activating adjacent benign hair follicle melanocytes to produce melanin. This process could be due to cytokines or growth factors, such as c-kit ligand. Other possible causes could be related to chronic sun damage or melanin-producing malignant melanocytes.