Keratoacanthomas as a Complication of Dermal Filler Injections

Keratoacanthomas (KAs) are common squamous neoplasms that originate in the pilosebaceous glands. KAs are considered by some physicians to be well-differentiated squamous cell carcinomas. The exact cause of KAs is unknown; however, they are associated with sun exposure, genetic factors, immunosup pression, carcinogens, viruses, and trauma.

Histologically, a KA is characterized by deep, bulbous lobules of keratinizing, well-differentiated squa mous epithelium with a keratin-filled central crater. There is marked acanthosis with hyperkeratosis and little or no parakeratosis.

Multiple KAs may be classified as the Ferguson-Smith type, the Grzybowski type, and the Witten and Zak type. KAs grow rapidly and, in most cases, resolve spontaneously. Althoaugh KAs rarely progress to metastatic carcinoma, early diagnosis and treatment are recommended.

In this article, we describe a patient who developed multiple facial KAs after receiving dermal filler injections. The patient responded favorably to treatment with acitretin 50 mg once daily for 1 month. This is a rare presentation of KAs occurring after dermal filler injections.