A 77-year-old woman comes to the office due to a skin lesion. The patient first noticed it a few weeks ago when it grew rapidly and became painful. However, since she scheduled her appointment 3 weeks ago, the lesion has become somewhat smaller and less painful. Skin examination findings are as shown below: Which of the following is the most likely diagnosis of this patient's skin lesion?

Question

A 77-year-old woman comes to the office due to a skin lesion.  The patient first noticed it a few weeks ago when it grew rapidly and became painful.  However, since she scheduled her appointment 3 weeks ago, the lesion has become somewhat smaller and less painful.  Skin examination findings are as shown below:  Which of the following is the most likely diagnosis of this patient's skin lesion?

Quizplus · Accepted Answer

11ec25c8_d8b3_c6bb_bc81_a71c7b671d2b_MD0003_00 This patient has a keratoacanthoma, which presents as a rapidly growing nodule with ulceration and a central keratin plug. As in this patient, keratoacanthomas frequently regress and may resolve spontaneously over several months. Keratoacanthomas are most common in fair-skinned individuals and are often seen in areas of ultraviolet exposure (eg, face, forearms) or prior trauma. Although keratoacanthomas often have a benign course, there may be a relationship to squamous cell carcinoma, with some lesions occasionally undergoing malignant transformation. For this reason, keratoacanthomas usually warrant excisional biopsy to confirm the diagnosis. (Choice A) Basal cell carcinoma often presents as an ulcerated nodule on sun-exposed skin. However, it typically grows slowly and does not undergo spontaneous regression or form a central keratin plug. ulcerated nodule (Choice B) A cutaneous horn is a keratinaceous projection from the skin that can be seen in association with a number of benign (eg, seborrheic keratosis) and malignant (eg, squamous cell carcinoma) lesions. Cutaneous horns are typically conical or elongated and do not generally undergo rapid regression. keratinaceous projection (Choice C) A dermatofibroma is a small, firm, hyperpigmented nodule, most often located on the extremities. The lesion has a fibrous component that may cause dimpling in the center when the area is pinched (dimple or buttonhole sign), but ulceration and keratin plug formation are not seen. hyperpigmented nodule (Choice E) Molluscum contagiosum typically presents as umbilicated nodules, but large ulcers and keratin plug formation are not present. Educational objective: A keratoacanthoma presents as a rapidly growing nodule with ulceration and a central keratin plug. It frequently regresses and may resolve spontaneously over several months. Although keratoacanthomas often have a benign course, some lesions may progress to invasive squamous cell carcinoma. References: Keratoacanthoma (KA): an update and review. (http://www.ncbi.nlm.nih.gov/pubmed/26853179)

A 77-Year-Old Woman Comes to the Office Due to a Skin