A Case Report of A Rare Giant Parotid Pleomorphic Adenoma with Atypical Preoperative Cytological Presentation of Category-IVB SUMP.

Abstract

Giant pleomorphic adenomas of the parotid gland are rare, particularly in younger patients, and their preoperative cytological evaluation can be challenging. The Milan System for Reporting Salivary Gland Cytopathology (MILAN) provides a framework for categorizing salivary gland lesions, but atypical presentations complicate diagnosis. A 31 year-old female presented with a large parotid mass, clinically suggestive of a giant pleomorphic adenoma. Preoperative fine needle aspiration cytology (FNAC) was atypical, categorized as SUMP (Salivary gland neoplasm of undetermined malignant potential) according to the MILAN system. The cytological features included cellularity with varying degrees of atypia and occasional necrotic debris, which raised concerns about the potential for malignancy. Subsequent surgical resection confirmed the diagnosis of a giant pleomorphic adenoma, measuring 13 cm in maximum dimension. Histopathological examination revealed classic features of pleomorphic adenoma with no evidence of malignancy. The atypical cytological presentation was attributed to the large size of the tumor and its degenerative changes. This case highlights the diagnostic challenges of atypical cytological findings in large pleomorphic adenomas. The MILAN system, while effective, may require careful interpretation in cases with significant tumor size and atypical features. Accurate diagnosis necessitates correlation of cytological findings with clinical and histopathological data.