Ultrastructural and immunohistochemical studies of reactive and adaptive transformations of the greater omentum at tumor lesions of the ovaries

The greater omentum is an organ in which metastases of malignant neoplasms of the female reproductive system are often formed. The issues of adaptive and reactive transformations of the greater omentum under conditions of a tumor process in the organs of the female reproductive system have been insufficiently studied. The aim of the study was to elucidate morphological and functional ultrastructural and immune-histochemical changes in the greater omentum in women with ovarian tumor lesions. Using the methods of light and electron microscopy, immunohistochemistry and morphometry, the ovaries of 48 women were examined, who were diagnosed with poorly differentiated serous-papillary adenocarcinoma stage II (20 patients, group 1), stage III (28 patients, group 2). In stage III patients, numerous tumor metastases were detected in the greater omentum. The results of the study showed that in the patients of the 2nd group, in the peri-tumor areas of the greater omentum, the vessels of the microvasculature were dilated, in the connective tissue, moderate edema and leukocyte infiltration were observed. Immuno-histochemical markers showed an increase in the number of immunocompetent cells, mainly T-lymphocytes in the tumor and in the peri-tumor areas. In the tumor and in the surrounding areas of the greater omentum, the process of neoplasm of blood capillaries was noted, differences in the density of collagen fibrils in different parts of the serous membrane were revealed, and the presence of numerous holes was shown, the sizes of which were reduced in areas with metastases. The results obtained show the adaptive and reparative capabilities of the structures of the greater omentum during the tumor process in the organs of the female reproductive system, indicate the important role of the greater omentum in providing protective reactions in the abdominal cavity. In response to the invasion of tumor cells, the processes of angiogenesis are activated in the greater omentum, and the number of immunocompetent cells increases in neo-lymphogenesis. The materials of the study indicate a significant plasticity and reactivity of the greater omentum under conditions of a tumor process in the body. However, the presence of a pronounced proliferative activity of tumor cells in tumor metastases indicates that these adaptive capacities are insufficient to resist tumor invasion into the greater omentum.