Cystadenocarcinoma: Report of a Rare Case in Oral Cavity

Cystadenocarcinoma is a rare tumor of the oral cavity, recently reclassified by the World Health Organization as synonymous with adenocarcinoma, not otherwise specified. This report describes a case of cystadenocarcinoma in the buccal mucosa. A 72-year-old woman was referred for diagnosis of a lesion, of unknown duration, located in the right buccal mucosa. Intraorally, the lesion appeared as a well-delimited, mobile, and submucosal nodule. A benign mesenchymal neoplasm was the main hypothesis of diagnosis. Microscopic analysis revealed a salivary gland neoplasm formed by atypical cells arranged in microcystic structures, with frequent intraluminal papillary projections. The tumor cells exhibited positivity for CK7 and negativity for CK20. Based on these features, a diagnosis of cystadenocarcinoma was established. The patient was submitted to wide surgical resection. No recurrence was observed after 12 months. Although rare, cystadenocarcinoma should be considered in the differential diagnosis of oral submucosal nodules.