A Case of Rapid Transformation of a Nail Matrix Nevi to Melanoma After Messenger RNA COVID-19 Vaccine: A Cause or a Coincidence?

Subungual melanoma is a variant of acral lentiginous melanoma that arises from the nail matrix. Subungual melanomas present unique clinical challenges due to diagnostic difficulties and the lack of a standardized protocol for surveillance, also, there are no evidence-based studies that determine the ideal frequency and duration of clinical and dermoscopy follow-ups in patients with longitudinal melanonychia. This is highlighted by a case of longitudinal melanonychia in a 53-year-old patient who underwent malignant transformation to subungual melanoma after a biphasic growth. Another problem raised is how long to observe longitudinal melanonychia, with the conclusion that it should be observed for lifetime. Finally, this report also illustrates the possible role of the COVID-19 messenger RNA vaccine in cancer development and/or progression.