HYALINE GLOBULES IN RENAL-CELL CARCINOMAS AND ONCOCYTOMAS

Hyaline globules (extracellular collections of amorphous material) are identified in 10 of 59 renal cell carcinomas (RCC) and in 2 of 9 onco cytomas. Immunohistochemical characterization of these PAS-positive st ructures revealed the presence of basement membrane material in most c ases. Collagen type IV and laminin were the predominant constituents, whereas fibronectin was detected only occasionally. Electron microscop ic examination of the globules showed concentric multilayered accumula tions of basement membrane material. No such structures were recognize d in 8 renal pelvic transitional cell carcinomas nor in 2 metanephric adenomas. RCC associated hyaline globules were always negative for alp ha(1)-antitrypsin (AAT), alpha-fetoprotein (AFP), amyloid A, cytokerat in, vimentin, or lysozyme.