[Differential diagnosis of epithelial thymoma and seminoma (histological and electron-microscopic study)].

The paper describes two observations of thymus gland tumours: epithelial thymoma and seminoma. Differential diagnosis of these tumours is very important for the proper selection of the method of treatment as seminoma is more radio-sensitive than epithelial thymoma. Epithelial thymoma is characterized by coarse-fiber stroma, perivascular grouping of cell elements and the lack of glycogen in them. Seminoma consists of light and dark cells containing much glycogen in their cytoplasm. Differences between these tumours are most clearly seen in electron microscopic studies. In epithelial thymoma cells have processes, numerous tonofilaments, desmosomes, and basal membrane. Seminoma cells contain glycogen, no tonofilaments or basal membrane, few desmosomes.