[Ultrastructural cytochemistry of epithelial gland-like component in synovial sarcoma]

In order to analyze the mucoid substance in the epithelial component of synovial sarcoma, electron microscopic and cytochemical studies were made on three of these neoplasms. The mucoid substances in the glandular lumen were intensely stained with ruthenium red (RR), appearing as granular, fibrillar and amorphous structures. RR staining of proteoglycans was diminished after treatment with chondroitinase AC or ABC, and was partially diminished by exposure to streptomyces hyaluronidase. Trypsin treatment did not affect RR staining of proteoglycans in the lumen. On thin sections stained with periodic acid-thiocarbo-hydrazide-silver proteinate (PA-TCH-SP), deposits of reaction product were observed on the mucoid substances within the lumen, and were localized in the Golgi complex, including the rough endoplasmic reticulum, small vesicle and lysosome-like dense body. Trypsin digestion decreased the stain intensity of PA-TCH-SP. These results indicate that the lumen of the gland-like component contains glycoproteins as well as proteoglycans mainly consisting of chondroitin sulfate and hyaluronic acid, and suggest that GERL (Novikoff) is closely related to production, storage and transport of glycoproteins in the cytoplasm of tumor cells.