Recurrent facial keratoacanthoma in a patient with diabetes: a case report

BACKGROUND: Keratoacanthoma is a relatively common low-grade malignancy that originates in the pilosebaceous glands. Pathologically, it closely resembles squamous cell carcinoma. Keratoacanthoma is believed to have a good prognosis; however, it has been reclassified as squamous cell carcinoma, keratoacanthoma type, to reflect the difficulty in histologic differentiation of this lesion as well as its uncommon but potentially aggressive nature. Keratoacanthoma infrequently presents as multiple tumors and may enlarge (5–15 cm), become locally aggressive, and rarely metastasize. CASE PRESENTATION: A 66-year-old Arab male patient with diabetes was referred to the Maxillofacial Surgery Department with a chief complaint of a dome-shaped nodule with a smooth, shiny surface and central crateriform ulceration with a keratin plug in the form of a horn-like projection. Skin papules were present in the right lateral canthal area and extended to the lateral border of the lower eyelid, measuring 1.3 cm. On palpation, the lesion was firm, movable, and tender. The patient had a history of a similar lesion in another area of his face that had spontaneously regressed. CONCLUSION: Histological differentiation between keratoacanthoma and well-differentiated squamous cell carcinoma is difficult, particularly when a secondary infection is present. Careful establishment of the correlation among the history, clinical findings, and histopathology is highly indicated to avoid unnecessary surgical intervention.