Ultrastructure of Glial Brain Tumors and Pathomorphological Assessment of Changes after Cryodestruction

Background: The role of cryosurgery in modern oncological practice is steadily growing now. Stereotactic cryodestruction of gliomas is one of minimally invasive techniques that helps to carry out more sparing surgical interventions in patients with glial tumors of deep, functionally significant structures. This study was aimed at studying the effects of cryoablation at the cellular level.

Materials and Methods: The authors analyzed the results of histological examination of the surgical material of 6 patients with supratentorial glial brain tumors of various degrees of malignancy. The sampling of the material for the study was carried out immediately before the introduction and after the extraction of the cryoprobe.

Results: A comparative electron microscopic examination in the areas of glial tumors after the cryodestruction showed manifestations of its gross destruction: ruptures of nervous tissue, fragmentation of the cytolemma and karyolemma, vacuoles of various sizes, including near the nucleus, various disorders of the chromatin structure, accumulation of gliofibrils in the absence of other organelles. The structure of myelin fibers in the glioma site after the cryotherapy was very diverse: there were myelin fibers with intense myelinopathy and axonopathy. The neuropile around the cells had a low electron density, or bundles of gliofibrils were found in it.

Conclusions: At EME of tumor tissue we found not only the specific, previously described signs of damage at the tissue level, but also the ultrastructural changes. The presented results show that the tumor cryodestruction not only results in direct destruction of tumor cells, but also triggers other mechanisms of glioma cell death. The above points to the need for prospective randomized controlled clinical studies with a large number of patients to determine the effectiveness of this promising method for the treatment of patients with glial brain tumors.