VEGF, a potent angiogenic factor, increases vascular permeability and induces the fluid accumulation in the peritoneal and pleural cavities. This study is designed to know whether the VEGF concentration are associated with the formation of cystic fluid of thyroid nodules and the results of treatment.

To know whether thyroid follicular cells produce VEGF, we measured the VEGF concentration in the conditioned medium after primary culture of the normal thyroid follicular cells (NT 1.0). Thirty seven patients, who had visited Ajou University Medical Center, were divided into two groups; group A (n=19) is patients whose cystic nodules disappeared completely with 1 or 2 times fine needle aspirations. In Group B (n=18), the cystic nodules recurred rapidly and required aspiration more than 3 times. Clinical records of patients were analyzed and compared with TSH and VEGF levels in cystic fluids.

The VEGF concentration in basal conditioned medium were 8.2±1.2 ng/ml in NT 1.0 and 8.2±0.6 ng/ml in thyroid cancer cell line (FTC-133). NT 1.0 was not affected by TSH stimulation. Mean concentration of TSH of all cystic fluids was 4.36µIU/ml (0.13~21.7) and there was no difference between 2 groups. Mean concentration of VEGF of all cystic fluids was 140.7 ng/ml (11.1~688.8). The VEGF concentration (287.9±289.6 ng/ml) in group B was significantly higher than that (104.2±97.1 ng/ml) in group A (P<0.05).

This study suggests that thyroid follicular cells produce and secrete VEGF, and VEGF is related with the accumulation of cystic fluid in degenerative cysts of thyroid. Cysts with high VEGF concentration promote rapid reaccumulation of the cystic fluid and possibly necessitate operation in selected patients.