Benign and malignant oncocytoma

Abstract

s ONCOCYTES I designated a special type A of epithelial cells arising through a transformation of epithelial cells in different or- gans.l7 They are characterized by their larger size compared with the original cells; the cytoplasm is more or less densely filled with more or less acidopliilic granules that sometimes coalesce and make the cytoplasm look almost homogeneous. Thus one can distinguish between pale, dark, and "colloid" oncocytes (Figs. 7, 12, and 13) following the nomenclature used for the oncocytes of the parathyroid gland,32 the oxyphil cells of Welsh. Electronmicroscopy studies36 showed that the cytoplasm is extremely rich in mitochondria. Histochemically, it is characterized by the abundance of oxydative enzymes?* 12, 3 4 9 35 and the presence of adenosine triphosphatase (ATPaSe).lG The presence of lipids is suggested by a very weak staining with Sudan, by a strong one (Fig. This histochemical characterization applies equally to the oncoqtes of the salivary glands12 as to those of the thyroid35 and p a r a t h y r ~i d ~~ and oncocytes in tumors of the thyroid (Figs.