THE CHALLENGE OF DIFFERENTIAL DIAGNOSIS BETWEEN SQUAMOUS CELL CARCINOMA AND KERATOACANTHOMA

• Published in: Oral surgery, oral medicine, oral pathology and oral radiology Vol. 137; no. 6; p. e159
• Main Authors: REIA, Verônica Caroline Brito, TOBIAS, Mattheus Augusto Siscotto, VIOLA, Vivian Palata, CORACIN, Fábio Luiz, LARA, Vanessa Soares, SANTOS, Paulo Sérgio da Silva
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.06.2024
• ISSN: 2212-4403; 2212-4411
• DOI: 10.1016/j.oooo.2023.12.054

A 57-year-old white man with a history of sun exposure presented with a complaint of a "lesion on the lip that sometimes gets better," with an evolution of 1 year. Physical examination: dry lips, loss of mucocutaneous border on the lower lip, sessile nodule of 1 cm, yellowish, reddish borders, well-defined, crusted surface, painless, on the right side. The diagnostic hypotheses were keratoacanthoma and squamous cell carcinoma (SCC); incisional biopsy was performed. Microscopy showed fibrous connective tissue, numerous epithelial islets with dysplasia, in the center keratin accumulations, corneal beads surrounded by intense mononuclear or polymorphonuclear inflammatory infiltrate, without solar elastosis. Suprajacent, hyperkeratinized stratified epithelial lining, sometimes with a verrucous appearance resulting in keratin-filled endophytic channels. After 7 days of the biopsy, there was erythema, expected tissue repair, and in 3 months, complete disappearance of the lesion and the presence of a scar in the region. Final diagnosis of keratoacanthoma, complex due to the significant histological similarities with SCC, but with an elucidative clinical response in the diagnosis."