Acinic cell carcinoma of salivary gland with massive deposits of globular amyloid

We present the case of a 23-year-old woman with a parotid gland tumor, the fine-needle aspiration biopsy smears of which showed epithelial cells with wide cytoplasm, isolated or arranged in micropapillary groups together with psammoma bodies. The surgical specimen contained a 5-cm tumor with the histologic features of an acinic cell carcinoma (ACC) with papillary areas. Notably, the cells of the tumor seemed to follow a sequence from large cells with rounded nuclei with open chromatin and prominent nucleoli to vacuolated cells with granular material, and finally to cells undergoing apoptosis. This finding was followed by the appearance of concentrically laminated, round to polygonal, Congo red-positive, birefringent bodies that in areas accumulated and formed extensive areas with massive deposits. The picture suggested that those amyloid bodies (psammoma bodies) resulted from the accumulation of residual masses of apoptotic cells. Huge globular amyloid deposits, the suggested name for this material irrespective of the type of amyloid, have not been previously reported in ACC of salivary gland.