This combination of vascular features with excess keratin fit perfectly with the name of the diagnosis: angiokeratoma. The dark color of the lesion on magnification, or in this case with dermoscopy, showed the lacunar pattern of dilated vessels. The overlying keratin was likely accentuated because it was on an extensor surface; the rim of hyperpigmentation is common for these lesions.
Angiokeratomas result from dilation of the blood vessels underneath the epidermis. There are different inciting events that lead to the 5 different types of angiokeratomas. The overlying epidermal changes are secondary to the underlying process of capillary ectasia.1 This lesion was not part of a cluster, so it was characterized as a solitary angiokeratoma. Smaller lesions are usually less keratinized and are commonly seen on the scrotum and vulva, where there are usually multiple lesions (referred to as angiokeratoma of Fordyce).
Zaballos2 studied the dermoscopic characteristics of 32 solitary angiokeratomas and reported 6 findings in at least half of the solitary lesions. The most common features were dark lacunae in 94% of the lesions, white veil in 91%, and erythema in 69%. Peripheral erythema, red lacunae, and hemorrhagic crusts were all seen at a rate of 53%. The most common location was the lower extremities.
This patient’s previous pathology report from a shave biopsy was found, confirming that the original diagnosis was angiokeratoma. Since the patient’s lesion had not resolved and was symptomatic from minor trauma, he was scheduled to come back in for an elliptical excision to remove the lesion.
Image and text courtesy of Daniel Stulberg, MD, FAAFP, Professor and Chair, Department of Family and Community Medicine, Western Michigan University Homer Stryker, MD School of Medicine, Kalamazoo.