Recurrent Acinic Cell Carcinoma of Parotid Gland Diagnosed by Fine Needle Aspiration Cytology: A Rare Case Report

Acinic cell carcinoma (ACC) is a rare malignant tumor of the head and neck region. It accounts for 12.4%–17.4% of parotid gland malignancies and approximately 3.4% of all salivary gland tumors. ACC is a low-grade salivary gland malignancy that predominantly affects females. In some cases, ACC can undergo high-grade transformation (HGT), resulting in more aggressive behavior. Here, we present a rare case of recurrent Acinic cell carcinoma with aggressive features and high-grade cytomorphology—including increased cellularity, papillary and singly scattered cells, high nuclear-to-cytoplasmic (N:C) ratio, coarse chromatin, and single-cell necrosis in the background—diagnosed via fine-needle aspiration cytology (FNAC) and further confirmed by histopathology and immunohistochemistry. This case can be categorized as ACC recurrence associated with high-grade transformation (HGT).