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

ABSTRACT

Papillary cystadenocarcinoma (PCAC) is a rare salivary gland tumor characterized by a predominantly cystic growth that often exhibits intraluminal papillary growth without specific histologic features of other cystic salivary gland tumors. The preoperative cytological diagnosis can pose a diagnostic challenge as it has to be differentiated from other cystic papillary tumors such as mucoepidermoid carcinoma, papillary cystic variant of acinic cell carcinoma, and low‑grade cribriform CAC. It is 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 male diagnosed on fine needle aspiration cytology. Although it showed mild atypia cytologically, on excision tumor showed vascular and perineural invasion with regional node metastasis indicating a wider morphologic spectrum than what is described. This prompted us to write a case report describing the cytological and histological features of this rare tumor and also discuss the diagnostic challenges.