Large, firm, erythematous, nodular lesions with central keratin plugs that arise rapidly are the hallmark of keratoacanthomas (KAs).
KAs commonly manifest on the hands and face and can alarm patients who are unfamiliar with their rapid growth. Since KAs can involute spontaneously after their growth and scarring phase, they were previously regarded as a benign lesion. KAs have a characteristic central keratin plug; this contrasts with basal cell carcinomas, which have central ulceration or scabbing. Currently, KAs are considered a subtype of squamous cell carcinoma (SCC). KAs tend to grow much faster and are raised, unlike SCCs, which normally have scale surrounding macular or slightly raised erythematous tissue.
Treatments include surgical excision, cryosurgery, curettage with electrodesiccation, topical 5-fluorouracil, imiquimod, intralesional methotrexate, or bleomycin.1 The isolated form of KAs is most common, but there are syndromes of multiple KAs that can be treated with systemic retinoids.
For this patient, the KA was transected across the base level with the surrounding skin and sent for pathology. At the same visit, the base was curetted down to the dermis and treated with electrodesiccation. This was followed by a repeat cycle of curettage and electrodesiccation. The patient was advised that if the pathology report showed invasive SCC, excision with margins would be recommended; otherwise, she would be followed clinically. Pathology did confirm a KA type of SCC. At the 6-week follow-up, the area was healing well, with no evidence of recurrence.
Photo and text courtesy of Daniel Stulberg, MD, FAAFP, Department of Family and Community Medicine, University of New Mexico School of Medicine, Albuquerque