Papillary Thyroid Microcarcinoma in Thyroid Surgical Practice: Incidental vs. Non-Incidental: A Ten-Year Comparative Study

Background/Objectives: With evolving guidelines favoring de-escalation in the management of papillary thyroid microcarcinoma (PTMC), options such as active surveillance and minimally invasive procedures are now considered for patients with low-risk disease. However, a subset of PTMCs—particularly non-incidental cases—may exhibit aggressive behavior. This study compares disease characteristics and outcomes between incidental and non-incidental PTMCs over a 10-year period. Methods: This is a single-center retrospective comparative analysis utilizing a prospectively collected database of patients referred for thyroid surgery. Results: Papillary thyroid carcinoma accounted for 86.7% of thyroid malignancies, with PTMC comprising 36.2% (137 patients). Incidental PTMC represented 109 out of 1012 patients undergoing surgery for benign thyroid disease (10.8%). Non-incidental PTMC (NIPTMC), diagnosed preoperatively and presenting clinically without coexisting thyroid disease, was identified in 28 patients (20.4%). NIPTMCs were more frequently associated with high-risk features (75% vs. 10.1%, p = 0.004), including extrathyroidal extension (21.43% vs. 7.3% p = 0.0015), positive central lymph nodes (21.43% vs. 2.8%, p = 0.0291), positive lateral lymph nodes (28.6% vs. 0% p = 0.012), and lymphovascular invasion (3.6% vs. 0%). Multifocal PTMC was seen in 37 patients (27%), of which 27 had bilobar disease. Multifocal tumors had a higher likelihood of high-risk features (48.6% vs. 14%, p = 0.007). NIPTMC was a significant predictor of multifocality (p = 0.0098). All patients underwent surgery, none opted for active surveillance. Conclusions: NIPTMC is more often associated with high-risk features and multifocality, necessitating more extensive surgery. These findings emphasize the need for careful preoperative risk stratification to guide individualized management.