Endocrine Abstracts

The aim of the study was investigating of microvessels density (MD) and expression of vascular endothelial growth factor (VEGF) in adrenocortical tumors.

Under investigation there were 23 adrenocortical tumors: adenomas – 13, ‘border’ tumors – 4, and carcinomas – 6. Immunohistochemical studied were carried out using monoclonal antibodies to both VEGF and endothelial marker CD34 (Dako). VEGF expression was estimated as a weak one (+), moderate (++), and intensive (+++).

The degree of vascularization of adrenocortical adenomas was high. In this case, the distribution of capillaries through the tumor tissue was relatively even and they surrounded small cell groups or sometimes single cells. VEGF expression in these tumor cells was either indefinable or weak (+), approximately 50% of cells like little granules localized predominantly along cellular membrane. In the ‘border’ tumors, an extremely uneven MD was noted. In this case, in addition to narrow-lumen capillaries, significant amount of sinusoids were revealed which prevailed here and there. Microgranular or diffuse VEGF expression was observed in the tumor cellular cytoplasm (++), predominantly in the foci of hypervascularization. Adrenocortical carcinomas had a little number of vessels within cell clusters. Usually, there were not numerous narrow-lumen capillaries or vascular ‘buds’ consisting of endothelial cell strands. Thin-wall sinusoids divided tumor lobes; in connective layers and pseudocapsule, they formed narrow-wall angioma-like structures. Intensive diffuse VEGF expression was determined in the tumor cell cytoplasm both in the central areas of the tumor (++) and in the peripheral growth areas where its intensity reached ‘+++’.

The outcome obtained is indicative of the fact that VEGF expression in the adrenocortical tumor cells is inversely related to the degree of their vascularization: the higher the VEGF level in tumor cells, the lower the MD, and vice versa. Biological significance of this fact is unclear. However, one can consider that VEGF expression and estimation of MD (reaction with CD34) in adrenocortical tumors might serve an additional criterion for evaluation of their malignant potential.