Multicentricity Is More Common in Thyroid Papillary Microcancer with a Preoperative Diagnosis Compared to Incidental Microcancer.

Objective: Although multicentricity is a common feature of thyroid papillary microcancer, it might be difficult to predict this histopathological feature preoperatively.

Methods: The records of 306 papillary microcancer patients who underwent thyroidectomy were evaluated. Papillary microcancer was diagnosed as an incidental histopathological finding in 242 (group 1), and by preoperative fine-needle aspiration biopsy in 64 (group 2). Demographic data and histopathological features were compared between the two groups.

Results: Age (44 ± 11.4 vs. 43 ± 14 years) and male/female ratio (44/193 vs. 12/52) showed no significant difference between groups 1 and 2 (p > 0.05). Mean tumor size was significantly larger in group 2 (5.2 ± 2.8 mm) compared to group 1 (3.7 ± 2.4 mm) ( = 0.004). The frequency of thyroid capsule invasion (44 vs. 19%, = 0.0001), microscopic extrathyroidal invasion (25 vs. 10%, = 0.004) and multicentricity (44 vs. 29%, = 0.04), and bilateral lobar involvement (22 vs. 10%, = 0.0001) was significantly higher in group 2 compared to group 1.

Conclusion: Multicentricity with bilateral lobar involvement and aggressive histopathological features are more frequent in papillary microcancer patients diagnosed with preoperative fine-needle aspiration biopsy compared to papillary microcancer diagnosed as postoperative incidental histopathological finding.