(BMJ)—A man in his 70s had a growing, tender lesion where he had hit his head 6 months prior. Exam: scaly, keratinized nodule with 2 lobules, resembling a stylized heart. Excisional bx confirmed the dx. What is it?
Verrucous carcinoma
Cutaneous squamous cell carcinoma
Cutaneous horn
You are correct. Histology confirmed a benign keratoacanthoma. Urgent excision is recommended for keratoacanthomas because of their similar presentation and clinical resemblance to cutaneous squamous cell carcinoma, other malignant lesions, and cutaneous horn (a.k.a. cornu cutaneum), another exophytic hyperkeratotic lesion. Dx is often made on histological exam. Sporotrichosis lesions occur more commonly on the distal extremities.

BMJ 2022;377:e070209