Background: Living-donor kidney transplantation tend to be more common in Asian countries. Previous studies have shown that donor nephrectomy does not increase operation-related mortality or end-stage renal disease (ESRD) risks in usual healthy donors. However, these results were based on studies performed in western countries, and only few results have been reported in the Asian population including Korea. We aimed to analyze the short and long-term risks of living kidney donors in Korea. Methods: We retrospectively analyzed medical records of 1,352 patients who had undergone donor nephrectomy from August 2005 to December 2020 at Seoul St. Marys Hospital. We collected baseline characteristics such as obesity, hypertension, dyslipidemia, diabetes, and GFR. Immediate postoperative complications were graded according to the Clavien-Dindo classification. Hemoglobin, BUN, Cr, GFR, proteinuria, glucose, cholesterol, and triglyceride levels were assessed at regular follow-up intervals. Long-term mortality and incidence of comorbidities were also assessed. Results: Of the 1,352 patients, 740 patients had 5-year follow-up results, and 137 patients had 10-year follow-up results. Five (0.4%) patients had severe postoperative complications; one patient requiring ICU care due to postoperative bleeding. Before donation, 3.0% were hypertensive, 4.7% had dyslipidemia, and 0.1% were diabetic. After donation, 5.8% were hypertensive, 4.9% had dyslipidemia, and 0.1% had diabetes. All donors had eGFR above 60 mL/min/1.732 before nephrectomy, but 19.7% donors showed eGFR below 60 after long-term follow-up, and 4.9% reached eGFR below 40. No mortality or ESRD requiring hemodialysis were reported during follow-up. Conclusions: Donor nephrectomy is a safe procedure with low risk of operation related complications. There was no significant difference in renal function, or cardiovascular comorbidities in donors compared to the healthy population. Limitations of our study was that the donors were from a single center, and many were lost during follow-up. Further studies including data from donors before 2005 may show additional outcomes, on mortality and renal failure.

Background: Criteria for the preoperative diagnosis of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) have not yet been confirmed. This study aimed to analyze differences in clinicopathological characteristics between follicular variant of papillary thyroid carcinoma (FVPTC) subtypes to determine which parameters are relevant in differentiating NIFTP from other variants. Methods: We retrospectively analyzed the records of 199 patients with a preoperative diagnosis of FVPTC who underwent thyroid surgery at Seoul St. Mary’s Hospital (Seoul, Korea) from 2011 to 2015. Clinicopathological features were analyzed retrospectively via a complete review of medical charts and pathology reports of patients. Results: The NIFTP and invasive encapsulated FVPTC (EFVPTC) groups showed relatively benign features, with a majority of the patients categorized as Bethesda category III (25.8% and 25.6%, respectively) or IV (34.8% and 30.2%, respectively), while the infiltrative FVPTC group showed more malignant features, with more patients categorized as category V (28.6%) or VI (47.6%) ( p < 0.001). BRAF V600E mutations were significantly less prevalent in the NIFTP group (0%) and invasive EFVPTC group (4.7%) compared with the infiltrative FVPTC group (34.9%) ( p < 0.001). Multivariate analysis showed that absence of BRAF V600E mutation (OR 20.311, p = 0.004) and lymph node metastasis (odds ratio 10.237, p = 0.004) were significantly associated with NIFTP. Conclusion: Although Bethesda category was a statistically significant factor in distinguishing FVPTC subtypes, it was not effective in conclusively distinguishing NIFTP and invasive EFVPTC. Absence of BRAF V600E mutation and lymph node metastasis are important features in distinguishing NIFTP from other subtypes.