[Problems of the differential diagnosis and classification of liposarcomas (electron microscopy study)].

Ultrastructure of both liposarcomas of different histological types and those with non-verified diagnosis are studied. Liposarcomas are shown to contain a basic complex of ultrastructural features of lipid differentiation and different histological types of these tumours have, in principle, identical features varying in the degree of their expression. The questions of a differential diagnosis of liposarcomas and other tumours can be successfully solved on the basis of the above findings, and even more, a group of liposarcomas with a severe cataplasia that does not have histological analogues may be distinguished.

[Ultrastructure of human embryonal liposarcoma].

Human embryonal liposarcoma and embryonal fat have been studied histologically, in semithin sections, and electronmicroscopically. Specific ultrastructural features of embryonal liposarcomas allowing them to distinguish from other tumours are as follows: the presence of lipid vacuoles varying in size, number and structure, small mitochondria with dense matrix, specific filamentous apparatus, basal-like material in plasma cell membrane and in the intercellular space cytoplasmic sprouts forming peculiar "pockets" and general cell architectonics. Similarities and differences in the ultrastructure of embryonal liposarcomas and embryonal fat are found.

[Early oncological pathology of the stomach].

The paper reports the results of a study of 586 gastrobioptical and cytological preparations obtained in the course of endoscopic examination of 223 patients with gastritis, polyps and gastric ulcers and resected material from 46 patients who had small-size malignant tumors of the stomach (up to 1 cm in dia). Gastrobiopsy revealed dysplasia-like changes in the epithelium in 33% of cases of chronic gastric diseases. Dysplasia in the mucosa surrounding tumor was identified in all cancer patients.