Background. To evaluate thyroid cancer probability operating on follicular neoplasia.

Materials and methods. Retrospective examination of 86 patients that underwent surgery during the period 2000–2006 due to follicular neoplasia (n = 71) and suspected cancer (n = 15) diagnosed via fine needle aspiration biopsy of the thyroid gland. Sonography and intraoperative biopsy tests were performed. After the final histological test the patients were assigned to 2 groups: A – cancer of the thyroid gland (n = 24) and B – benign changes (n = 62).

Results. Hypoechogenic nodes of mononodal and multinodal goitre were typical for A group (p = 0.04). Cytological features for A group were: ruptures of cytoplasm through the nuclear membrane (4 out of 4 patients – 100%) (p = 0.06), inclusions of reddish colloid in the cytoplasm (4 out of 6 patients – 66.7%) (p = 0.34) and atypical cells (13 out of 25 patients – 52%) (p = 0.50). Out of 12 patients that had been diagnosed with cancer by the intraoperative biopsy test, the diagnosis was confirmed for 10 (83.3%), and benign changes were stated for 2 (16.7%) by final histological test.

Conclusions. Thyroid cancer was diagnosed both in the hypoechogenic mononadal and multinodal gland (p = 0.04). When follicular neoplasia was diagnosed by a cytological test, cancer of the thyroid gland was stated for 21.1% of patients by a histological test. Sensitivity of an intraoperative biopsy test was 55.6%, specificity was 93.1%.

Keywords: follicular neoplasia, thyroid cancer, cytological test, intraoperative biopsy test