Amylase crystalloids in fine needle aspiration cytology of parotid gland: A diagnostic challenge

Differential Diagnosis Under the Microscope: Crystalloid Granuloma of the Parotid Gland

“…While many crystalloids are nonspecific, a-amylase crystalloids have only been reported in benign lesions, and their identification may be helpful in distinguishing benign from malignant lesions. 1 Although these crystalloids are found in a variety of benign salivary gland tumors, they only rarely induce a granulomatous reaction, resulting in a condition known as ''crystalloid granuloma'' (CG). We present a case of CG in the parotid gland, misdiagnosed on cytopathology and subsequently surgically resected.…”

“…Amylase crystalloids have eosinophilic, variably shaped rectangular, polyhedral, rod-like, ovoid, and rhomboid structures (Figure 3 bottom). 1,2 Amylase crystalloids in the parotid gland are generally identified in sialadenitis, cystic lesions, and Warthin tumors. 3 Although other crystalloids may be seen in malignant salivary gland tumors, amylase crystalloids have only been reported in benign lesions.…”

“…Typically, amylase-type crystalloids are nonbirefringent rectangular structures, ranging between 5 and 500 µm in size. 1 The detection of amylase crystalloids on FNA, coupled with a benign appearance on imaging, suggests that surgery may be avoided in patients with a higher surgical risk.…”