When Crystalloids Tell the Story: Amylase Crystalloids in Salivary Gland Cytology

Crystalloids in salivary gland cytology are uncommonly recognised findings that may provide important diagnostic clues in differentiating neoplastic from non-neoplastic lesions. Among these, amylase crystalloids are typically associated with benign salivary gland lesions, including inflammatory conditions such as sialadenitis and cystic lesions, as well as benign neoplasms such as Warthin tumour and pleomorphic adenoma. We describe a case of a 59-year-old female presenting with a parotid swelling. Ultrasonography revealed a cystic lesion in the parotid gland. Fine needle aspiration yielded yellowish fluid, and cytology smears revealed numerous nonbirefringent rectangular to rhomboidal crystalloids showing characteristic staining properties, consistent with amylase crystalloids, in a background of mixed inflammatory infiltrate. No epithelial component was identified. A diagnosis of chronic sialadenitis with amylase crystalloids (Milan Category II) was rendered. The lesion resolved post-aspiration with no recurrence on follow-up. Recognition of crystalloid morphology on cytology is essential, as it serves as a useful clue towards benign pathology and supports accurate diagnosis of benign salivary gland lesions.