Abstract

Adenoid cystic carcinomas (ACC) are slow growing, aggressive malignancies of the salivary glands. ACC is a rare head and neck carcinoma that has a tendency for local recurrence and distant metastasis. The gene fusion most commonly associated with ACC is MYB-NFIB, resulting from translocation t(6;9). Here we report a case of a 68-year-old male presenting with a progressively enlarging right lower lip nodule. The lesion was submucosal and extended to the gingival sulcus and right lower chin skin fixation. Histologically, the lesion presented as squamous mucosa with large solid nests lined by basaloid cells with variable moderate to severe nuclear atypia, desmoplastic stroma, and irregular nests comprising the majority of the tumor. Few cribriform-tubular structures are in the background, and there is pagetoid extension into the lower portion of a hair follicle. Tumor cells exhibited diffuse cytokeratin expression, Ber-EPA4, and diffusely strong CD117. No reactivity for P63, S100, D2-40, P40, or GATA3 was present. Molecular testing reveals novel YAP1-ZNF215 gene fusion. YAP1 is a transcription regulator known for its role in the development and progression of certain cancers. However, YAP1 is not known for its fusion with ZNF215 in ACC. Adenoid cystic carcinomas have an infiltrative growth pattern and are capable of perineural invasion. This patient underwent wide local excision with 1 cm circumferential margins and has no known recurrence to date. Our case contributes to the knowledge of adenoid cystic carcinomas with a unique molecular gene fusion.