Adenoid basal carcinoma with adenoid cystic-like features—a rare diagnostic dilemma

Introduction/Objective Adenoid basal carcinoma (ABC) of the cervix is a rare, indolent tumor with no known metastatic potential. The tumor is composed of small nests of bland, basaloid cells, which do not elicit a desmoplastic response within the surrounding stroma. Cystic and clear cell change, as well as glandular differentiation, are not unusual. As such, it is important to differentiate ABC from adenoid cystic carcinoma (ACC), particularly on account of the aggressive clinical course of the latter. We herein present a rare case of ABC with adenoid cystic-like features. Methods/Case Report A 74-year-old woman with an incidental ABC, diagnosed on an excisional procedure performed for a prior diagnosis of a high grade squamous intraepithelial lesion. Subsequent hysterectomy revealed a tumor composed of nests of basaloid cells, extending into the outer third of the cervical wall, but exhibiting no peri- tumoral desmoplasia. Cribriforming associated with increased mitotic activity was focally present and showed increased Ki-67 labeling compared to the solid nests of tumor. PAS special stain highlighted rare pseudolumina with basement membrane-like material. While these features were concerning for an ACC—the lack of any significant cytologic atypia, destructive stromal invasion, and a clinically apparent lesion—was consistent with an ABC with so- called adenoid cystic-like features. Results (if a Case Study enter NA) NA Conclusion Making an accurate diagnosis requires clinicopathologic correlation and awareness of histologic overlap. Additionally, adenoid cystic-like morphology in ABCs is a little-studied phenomenon, which necessitates further research to shed light on potential clinical implications.