Making a Difference: Blue Nevus versus Melanoma

Abstract

The blue nevus is an uncommon lesion that may appear worrisome due to its similar appearance to the sinister melanosarcoma. The blue nevus is a subset of dendritic melanocytic proliferations that is commonly believed to be remnant embryonal neural crest cells that failed to migrate from the dermis. This is a case of a 58-year-old male who presented with a bluish lump on his right third finger for 6 months complaining of dull ache, swelling and decreased range of motion (ROM). The impression of the lesion was of a blue nevus, a benign tumour that required investigation and follow up due to concern for a melanoma. His pain and decreased ROM can be attributed to repeated use due to his trade and were later deemed as a red herring presentation. Although histopathology continues to be the gold standard in the diagnosis and classification of melanocytic nevi lesions, ultrasound imaging can be considered as a quick tool to characterise and quantify such lesions as a preliminary exam to rule out more concerning features of melanomas.