A 62-year-old man presented to our family practice office with a skin lesion that developed over 8–10 months. Over the past 2–3 months the lesion grew more quickly. A 2–3 cm, hard brown projection was noted on the dorsal aspect of his hand. A decision was made to excise the lesion and send it for pathological evaluation. The lesion was found to be a cutaneous horn with invasive squamous cell carcinoma at the base. The margins of the sample were free of cancer cells. Cutaneous horns are raised skin lesions made of dead keratin derived from base keratinocytes. They are frequently found in areas of the body that have had solar exposure. There are a wide variety of histopathological findings at the base of these lesions. They range from benign to premalignant to malignant. Cutaneous horns should be completely excised and sent for pathological evaluation.
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This case is important because it exemplifies the necessity of performing excisional biopsies on these lesions and not performing shave excisions that can leave the base of the lesion intact.
This case also reminds us of the variety of the histopathological findings at the base of these lesions.
A 62-year-old, fair-skinned man with a long history of sun exposure presented to our office with the lesion seen in figure 1. The lesion was located on the dorsal aspect of his hand and was present for 8–10 months. He noted that over the past 2–3 months it was growing more quickly. The patient's medical history includes high-blood pressure and a 50 pack-year history of smoking. His lifelong employment was as an outdoor labourer causing him to have several areas of sun damage to his skin.
A decision was made to perform an excisional biopsy and send the sample for pathological evaluation. The results of the biopsy revealed a cutaneous horn with an invasive squamous cell carcinoma at the base of the lesion. The margins of the biopsy were clear of cancer cells.
The patient healed completely with minimal scarring and recovery of full function.
Samples, including the base of the lesion was sent for histopathological evaluation.
Differential diagnosis includes: verruca, capillary haemangioma, basal cell carcinoma, trichilemmal carcinoma and Kaposi's sarcoma.
Treatment consists of excisional biopsy of the cutaneous horn with margins of unaffected skin. Depending on the location Moh's surgery may be required.
Cutaneous horns or cornu cutaneum are hyperkeratotic projections of the skin resembling the horn of an animal.
They are usually conical in shape and are composed of dead keratin derived from base keratinocytes, and are usually grey to yellow in colour. These lesions have a wide variety of presentations and locations, but are most frequently in areas that have had solar exposure and damage.1 Cutaneous horns occur most frequently in light-skinned individuals older than 50 years of age and are more common in men.2 These lesions can be several centimetres in size. Despite the common finding of dead keratin and typical appearance of cutaneous horns, the base can have a wide assortment of histopathological findings from benign, premalignant to malignant. These include actinic keratosis, squamous cell carcinoma in situ, invasive squamous cell carcinoma, lentigo malignant melanoma, verruca, seborrhoeic keratosis, benign epithelial hyperplasia, trichilemmoma, capillary haemangioma, Kaposi's sarcoma and molluscum contagiosum.2 ,3
Owing to the wide variety of histopathological findings at the base of these lesions, it is important to completely excise the lesion at the base and send for pathological review.
Cutaneous horns are usually conical raised skin lesions that are grey to yellow in colour and are composed of dead keratin.
Cutaneous horns may have a focus of malignancy at the base.
Cutaneous horns should be excised at the base and sent for pathology.
Competing interests None.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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