Malignant transformation of white sponge nevus: a case report of a novel keratin 4 mutation.

BACKGROUND: White Sponge Nevus (WSN) is traditionally considered a benign genetic disorder affecting the oral mucosa, primarily caused by pathogenic mutations in keratin 4 (KRT4) or keratin 13 (KRT13). Despite its benign nature, recent evidence has begun to question the malignant potential of WSN. CASE PRESENTATION: We report a case involving a 70-year-old man who presented with a white lesion on the right floor of his mouth. Initial diagnostic evaluations confirmed the lesion as WSN. Over a one-year follow-up, the lesion underwent malignant transformation, evolving into local epithelial moderate-to-severe dysplasia. Exome sequencing identified a novel insertion mutation in exon 1 of the KRT4 gene, resulting in a deletion-insertion amino acid mutation involving glycine. Single-cell RNA sequencing further revealed altered epithelial proliferation and differentiation dynamics within the lesion. CONCLUSIONS: This case not only expands the known genetic spectrum of KRT4 mutations associated with WSN but also provides preliminary evidence suggesting the malignant potential of WSN. The novel pathogenic mutation in KRT4 is postulated to alter epithelial proliferation and differentiation, thereby raising concerns about the malignant transformation of WSN. Further studies are warranted to confirm these findings.

Role of biologics in refractory recurrent aphthous stomatitis.

Refractory recurrent aphthous stomatitis (RRAS) manifests as severe ulcerative lesions of the oral mucosa with poor healing and a poor response to conventional therapy, with or without systemic diseases. Its treatment remains a clinical challenge owing to the lack of effective therapies. Recently, biologics have emerged as promising targeted therapies for RRAS. The biologics targeting specific inflammatory pathways involved in the pathogenesis of RRAS, including tumor necrosis factor-alpha inhibitors and interleukin inhibitors, offer a more precise and promising therapeutic approach for RRAS. These targeted therapies have been shown to promote healing and decrease recurrence frequency in, and improve the quality of life of patients with RRAS. Herein, the types and mechanisms of biologics currently used to treat RRAS have been reviewed; furthermore, the dose, duration, therapeutic efficacy, and adverse effects of RRAS with or without certain associated systemic diseases, and the current problems and future directions have been discussed.