Ultrastructure of the acinic cell carcinoma and clear cell carcinoma of the parotid gland

Abstract

The acinic cell carcinoma and the clear cell carcinoma of the parotid are morphologically different neoplasms under electron microscopic examination. The former appears as a differentiated tumor, made of secretory serous acinar cells. The latter seems to arise from striated ducts and is composed of peculiar clear cells. These clear cells contain a large number of free ribosomes, a few mitochondria and very few other organelles. The “clear” appearance of the cytoplasm results from clumping and margination of the ribosomes after formalin fixation. These cells seem to be undifferentiated tumor cells with an RNA deficient ribosomal apparatus, which would partly explain the slow growth of these tumors.

Salivary acinic cell carcinoma: reappraisal and update

“…Echevarria's early electron microscopical investigation reported on the effects of preservation in effecting 'clear' cell phenotypes and illustrated complex phagosomes in tumor cells [80]. Later investigations using material specifically preserved for electron microscopy described variations in the electron density of the cytoplasmic granules in tumor cells [80][81][82]. These granules (Fig.…”

Ultrasound features of acinic cell carcinoma of the tongue: a rare case report

“…Four growth patterns have been described: solid, papillary cystic, follicular, and microcystic. The solid variant is characterized by numerous well‐differentiated acinar cells arranged in a pattern resembling normal parotid gland tissue 6, 12, 13, 15, 16. A solid growth pattern is the most easily recognized and dominant (38% of cases) morphological variant of acinic cell carcinoma; it is considered to be the “classic” pattern because it is typified by numerous well‐differentiated acinar cells and closely resembles a normal parotid gland 6.…”

“…Histologically, acinic cell carcinoma is composed mainly of differentiated glandular cells bearing secretory granules identical to those of the normal serous salivary acinus . Tumors in the minor salivary glands are histologically similar to those arising in the major salivary glands .…”

Ultrastructure of glycogen‐rich clear cell carcinoma of the palate

“…The trabeeular eareinoma of myothelial origin eonsists of two cell types: intercalated duct-like dark cells with few cytoplasmic organelles and elear eells rich in organelles and glycogen (Donath et al 1972). This tumor also differed from the clear cell carcinoma in that it lacked the elumping and margination of ribosomes (Eehevarria 1967).…”