Verruca vulgaris similarly contains puncta but typically appears as a raised lesion with a disruption of the stratum corneum.5
Acral melanoma can be distinguished from tache/talon noir by dermoscopic evaluation and/or paring of the corneum. On dermoscopic evaluation, both acral melanoma and tache/talon noir will reveal parallel ridge patterns; this finding has an 86% sensitivity and 96% specificity for early acral melanoma.6 What differentiates the 2 is the “satellite globules” or “pebbles on a ridge” that are seen with a subcorneal hematoma. Furthermore, paring the corneum would demonstrate an absence of blood within the ridges of the skin shavings, pointing away from tache/talon noir as the diagnosis.1-3,5-7
Traumatic tattoo can also mimic tache/talon noir, due to foreign-material deposits in the skin (gunpowder, carbon, lead, dirt, and asphalt). A history of penetrating trauma should help to narrow the differential. Attempts at paring with traumatic tattoo may or may not help with differentiation.1
In this case, time does heal all wounds
Talon/tache noir are benign conditions that do not require treatment and do not affect sports performance. The lesion will usually self-resolve within a matter of weeks from onset or can even be gently scraped with a sterile needle or blade, which can partially or completely remove the pigmentation from within the parallel ridges.3,5,8
Our patient was advised that the lesion would resolve on its own. His knee pain was determined to be a simple case of patellofemoral syndrome or “runner’s knee” and he opted to complete a home exercise program to obtain relief.