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Hyperpigmented lesion on palm

A 17-year-old high school baseball player presented for left anterior knee pain. During the exam, a hyperpigmented lesion was noted on the patient’s left palm. The patient was unsure of how long he’d had the lesion and said it did not bother him.

On closer examination, scattered black dots were noted within a 2 x 1–cm thickened keratotic plaque at the hypothenar eminence of the patient’s hand. There was no tenderness, erythema, warmth, or disruption of normal skin architecture or drainage.

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Hyperpigmented lesion on palm

This patient had a posttraumatic tache noir (also known as talon noir on the volar aspect of the feet); it is a subcorneal hematoma. The diagnosis is made clinically. Dermoscopic evaluation of tache/talon noir will reveal “pebbles on a ridge” or “satellite globules.” Confirmation of tache/talon noir can be made by paring the corneum with a #15 blade, which will reveal blood in the shavings and punctate lesions.1

This patient noted that the knob of his baseball bat rubbed the hypothenar eminence of his nondominant hand when he took a swing. The sheer force of the knob led to the subcorneal hematoma. Tache noir was high on the differential due to his physician’s clinical experience with similar cases. Tache noir occurs predominantly in people ages 12 to 24 years, without regard to gender.2 The condition is commonly found in athletes who participate in baseball, cricket, racquet sports, weightlifting, and rock climbing.2-4

Talon noir occurs most commonly in athletes who are frequently jumping, turning, and pivoting, as in football, basketball, tennis, and lacrosse.

Tache noir can be differentiated from other conditions by the presence of preserved architecture of the skin surface and punctate capillaries beneath the stratum corneum. The differential diagnosis includes verruca vulgaris, acral melanoma, and a traumatic tattoo.

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.

This 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.

This case was adapted from: Warden D. Hyperpigmented lesion on left palm. J Fam Pract. 2021;70:459-460. Photos courtesy of Daniel Warden, MD

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