Cytomorphological findings and histological correlation of papillary cystadenocarcinoma of the parotid: Not always a low-grade tumor

摘要

Papillary cystadenocarcinoma (PCAC) is a rare salivary gland tumor characterized by a predominantly cystic growth that often exhibits intraluminal papillary growthwithout specific histologic features of other cystic salivary gland tumors. The preoperative cytological diagnosis can pose a diagnostic challenge as it has to bedifferentiated from other cystic papillary tumors such as mucoepidermoid carcinoma, papillary cystic variant of acinic cell carcinoma, and low-grade cribriform CAC. Itis considered to be a low-grade malignant salivary gland tumor with an indolent biological behavior. We report a case of PCAC of the parotid in a 55-year-old malediagnosed on fine needle aspiration cytology. Although it showed mild atypia cytologically, on excision tumor showed vascular and perineural invasion with regionalnode metastasis indicating a wider morphologic spectrum than what is described. This prompted us to write a case report describing the cytological and histologicalfeatures of this rare tumor and also discuss the diagnostic challenges.