OBJECTIVE
Study of morphometric and ultrastructural features of follicular adenomas of the thyroid gland.
MATERIAL AND METHODS
The study was conducted on the surgical material of the thyroid glands of 11 patients with a preliminary cytological conclusion of “Follicular neoplasia” and a further histologically established diagnosis of “Follicular adenoma”. Material — fragments obtained from morphologically verified nodes of follicular adenoma, fragments of tissue outside the nodular formation served as control samples. Light and transmission electron microscopy were used to study semi-thin and ultra-thin sections of the thyroid glands, respectively. Morphometric analysis and statistical processing were performed on semi-thin sections.
RESULTS
In follicular adenoma, the formation of intracellular microfollicles and narrowing of the lumen of the follicles with hypertrophy of the tumor cells: a reliable increase in the area of cells and their nuclei (p≤0.01), the numerical density of mitochondria (p≤0.001), a decrease in the diameter of the follicles (p≤0.001) were noted. The common ultrastructural features of the studied follicular adenomas are heterogeneous changes in the synthetic apparatus against the background of a sharp increase in the number of mitochondria. A possible mechanism of morphological rearrangements of tumor cells in follicular adenoma is compensatory adaptation at the level of cellular energy systems in response to dysfunction of the synthetic apparatus of thyrocytes. In the studied follicular adenomas with classical microfollicular morphology, signs of other, rarer histological patterns were found in a number of cells or in individual follicles, in particular, signet ring cell and clear cell patterns.
CONCLUSION
The diversity of the detected morphological rearrangements reflects the stage-by-stage development of follicular adenomas. A number of ultrastructural features suggest that the rarer histological patterns described for follicular adenomas originate from the classical microfollicular pattern as a result of multidirectional transformation.
