A PubMed search of articles indexed for MEDLINE using the search term nevus spilus and melanoma yielded 2 cases4,8 of melanoma arising among 15 cases of hairy NS in the literature, which led to the suggestion that the presence of hair could be associated with an increased risk for malignant degeneration in NS (Table). This apparent high incidence of melanoma most likely reflects referral/publication bias rather than a statistically significant association. In fact, the clinical lesion most clinically similar to hairy NS is Becker nevus, with tan macules demonstrating lentiginous melanocytic hyperplasia associated with numerous coarse terminal hairs. There is no indication that Becker nevi have a considerable premalignant potential, though one case of melanoma arising in a Becker nevus has been reported.9 There is no evidence to suggest that classic CMN with hypertrichosis has a greater premalignant potential than similar lesions without hypertrichosis.
We noticed the presence of hair in our patient’s lesion only after reports in the literature caused us to look for this phenomenon.9 This occurrence may actually be quite common. We do not recommend prophylactic excision of NS and believe the risk for malignant degeneration is low in NS with or without hair, though larger NS (>4 cm), especially giant, zosteriform, or segmental lesions, may have a greater risk.1,6,9,10 It is prudent for physicians to carefully examine NS and sample suspicious foci, especially when patients describe a lesion as changing.