Nail dystrophy mostly affects thumb nail bilaterally, but single nail involving the middle finger has also been reported.11 A hangnail is a small, torn piece of skin, on eponychium or paronychium, next to a fingernail or toenail.

Each digital artery dives into the pulp at the distal phalanx level, giving off a branch parallel to the paronychium. This then subdivides into several small fine branches that supply the nail bed as it traverses distally.

Involvement of the eponychium and paronychium is common with advanced disease.

Many patients with subungual melanoma have a history of a thin pigmented streak that had remained unchanged for years and then suddenly began to enlarge--eventually involving the entire nail bed with subsequent penetration to the eponychium or paronychium, ulceration, or granuloma formation.

One or more of the following regions were sampled from each dog: axilla, groin, chin, ventral neck fold, paronychium, and interdigital spaces (dorsal or plantar) according to clinical signs.