Is partial ablation appropriate for benign thyroid nodules? A retrospective study with long-term follow-up after microwave ablation.

OBJECTIVE: This retrospective study aimed to investigate the efficacy and safety of partial ablation (PA) for benign thyroid nodules (BTNs) using microwave ablation (MWA) in a long-term follow-up. MATERIALS AND METHODS: Between February 2015 and April 2019, 236 patients with 236 BTNs (maximum diameter ≥2 cm) treated with ultrasound-guided MWA were enrolled. Contrast-enhanced ultrasound (CEUS) was performed within 3 d after ablation to determine whether there was residual tissue according to which the patients were assigned PA or complete ablation (CA). The volume reduction ratio (VRR) and complications were evaluated during follow-up. RESULTS: Eighty-two patients were enrolled in the PA group, and 154 were enrolled in the CA group. Both groups achieved continuous reductions in nodule volume and increases in VRR within 2 years after ablation. Although the VRR of the PA group at 4 years was lower than that of the CA group (65.54 vs. 95.08%; p<.05), PA still achieved 'technical efficacy' with a volume reduction of more than 50%. The complication and side effect rates between the two groups showed no significant difference (p>.05). CONCLUSIONS: Both PA and CA were safe and effective in reducing the volumes of BTNs in the long-term follow-up. For nodules with a large initial volume and dangerous location, PA with a small amount of residual tissue may be acceptable.

Laser and radiofrequency ablations for benign and malignant thyroid tumors.

A growing body of evidence is being published regarding the safety and efficacy of minimally invasive image-guided ablation techniques. While clinical applications of these techniques are increasing, international societies have started to publish treatment guidelines and to make efforts to standardize both terminology and reporting criteria for image-guided thyroid ablations. Laser ablation and radiofrequency ablation (RFA) are among the most common ablation techniques either for benign and malignant thyroid nodules. Unlike laser ablation and RFA in the treatment of benign thyroid nodules, where safety and efficacy have been widely demonstrated, evidence regarding local tumor control of thyroid malignancies is still limited. However, preliminary results are encouraging and image-guided thermal ablation techniques can be considered a valid alternative to surgery for the treatment of benign thyroid nodules and recurrent thyroid cancers. This review evaluates the basic concept of RFA and laser ablations, their techniques, clinical outcomes, and complications based on the suggestions of several society guidelines. Multidisciplinary collaboration remains critical to identify patients which may benefit from minimally invasive image-guided thermal ablations, especially if surgery or radioiodine therapy are not feasible options.

Thyroid malignancy markers on sonography are common in patients with benign thyroid disease and previous iodine deficiency.

OBJECTIVES: The purpose of this study was to evaluate the characteristics of benign thyroid nodules on sonography and ultrasound elastography in a population exposed to iodine deficiency. METHODS: We conducted a prospective systematic evaluation of preoperative thyroid sonography and elastography in patients assigned for surgical excision of benign thyroid nodules. Two experienced sonographers performed all sonographic and elastographic examinations. Thyroid nodules were evaluated by 7 generally accepted sonographic malignancy risk markers and assigned an elasticity score on elastography. The final diagnosis of a benign thyroid nodule was based on histopathologic analysis of resected thyroid gland tissue. RESULTS: We evaluated 232 thyroid nodules in 105 patients (86 women and 19 men). In total, 57% of the examined nodules had 1 or 2 malignancy risk markers present, and 24% did not have any markers present. A solid nodule larger than 15 mm was the most common malignancy risk marker observed (63%), followed by low elasticity (33%), microcalcifications (26%), and hypoechogenicity (15%). In an analysis stratified according to the number of nodules (solitary versus multiple), low elasticity was described more frequently in solitary nodules (61.9% versus 30.4%; P= .004). A large nodular volume was a predictor (P < .05) of microcalcifications and intranodular vascularization, whereas an absent halo sign and a solid nodule were found less frequently in nodules with larger volumes. CONCLUSIONS: Our results show that routine preoperative malignancy risk evaluation of presumably benign thyroid nodules is of little value when performed on patients exposed to iodine deficiency.

Solitary Necrotic Nodule of the Liver: A Benign Mimicker of Malignancy.

Solitary necrotic nodule (SNN) of the liver is an uncommon and benign finding in liver pathology. Typically, it appears as a single and asymptomatic lesion, primarily located at the subcapsular region of the right lobe of the liver. Unfortunately, it is easy to mistake this benign lesion for a primary or secondary neoplastic lesion, making it a potential diagnosis pitfall for liver malignancies. The diagnosis of SNN can be difficult to determine as the imaging findings frequently lack specificity. This brings out the importance of histomorphological examination to accurately identify this lesion, and to rule out any possible malignancies. We report here the case of a 35-year-old woman with a history of squamous cell carcinoma of the cervix, who presented a solitary nodule on her liver that was falsely diagnosed as a metastatic lesion in the liver at imagery. The aim of this article is to highlight the importance of using special stains and immunohistochemical staining for diagnosing SNN and excluding any necrotic metastases of the liver. We demonstrated that the absence of a reticulin meshwork in the necrotic core should prompt consideration of a necrotic metastasis in the liver, rather than a solitary necrotic nodule.

Oxidative stress mediates the associations between phthalate exposures and thyroid cancer/benign nodule risk.

Epidemiological studies have suggested that phthalate exposures are associated with increased risks of thyroid cancer and benign nodule, while the underlying mechanisms are largely unknown. Here, we explored the mediation effects of oxidative stress (OS) biomarkers in the associations between phthalate exposures and the risks of thyroid cancer and benign nodule. Urine samples collected from 143 thyroid cancer, 136 nodule patients, and 141 healthy controls were analyzed for 8 phthalate metabolites and 3 OS biomarkers [8-hydroxy-2-deoxyguanosine (8-OHdG), 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA), and 8-iso-prostaglandin F2α (8-isoPGF2α)]. Multivariable linear or logistic regression models were used to explore the associations of OS biomarkers with phthalate metabolite concentrations and the risks of thyroid cancer and nodule. The mediation role of OS biomarkers was also investigated. Urinary monoethyl phthalate (MEP), monomethyl phthalate (MMP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP), mono (2-ethylhexyl) phthalate (MEHP), and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) were positively associated with at least 2 OS biomarkers (all P-values<0.01), and part of these positive associations varied in different subgroups. All 3 OS biomarkers were positively associated with the risks of thyroid nodule and cancer (P-values<0.001). The mediation analysis showed that OS biomarkers significantly mediated the associations between urinary MEHOP concentration and nodule, as well as between urinary MMP, MEHP, and MEHHP concentrations and cancer and nodule, with the estimated proportions of mediation ranging from 15.8% to 85.6%. Our results suggest that OS is a potential mediating mechanism through which phthalate exposures induce thyroid carcinogenesis and nodular formation.

Identifying and Predicting Diverse Patterns of Benign Nodule Growth.

CONTEXT: The natural history of benign thyroid nodules is typically characterized by slow growth and minimal risk of malignant transformation. Available data have, to date, been unable to elucidate the diversity of benign nodule growth patterns over time nor predictive of which patients follow which pattern. OBJECTIVE: We aimed to better define the diverse patterns of benign nodule behavior and their predictors. METHODS: We prospectively studied 389 consecutive patients with solitary, solid, cytologically benign thyroid nodules ≥1 cm and follow-up ultrasound for at least 4 years. Demographic, sonographic, biochemical data were collected at initial evaluation, and subsequent growth patterns were identified over the follow-up. Predictors of growth at initial evaluation and 3 years of follow-up were defined. RESULTS: The mean (±SD) follow-up was 7.7 (±2.7) years. Three distinct growth patterns were identified: A) stagnant nodules with average growth rate < 0.2 mm/year; B) slow-growing nodules with a rate 0.2 to 1.0 mm/year; and C) fast-growing nodules increasing > 1.0 mm/year. Fast-growing nodules represented 17.2% of the cohort, and were more frequent in patients younger than 50 years (OR 2.2 [1.2-4.1], P = 0.016), and in larger nodules (2.0-2.9 cm, OR 3.5 [1.7-7.1], P = 0.001; >3.0 cm, OR 4.4 [1.8-10.4], P = 0.001 vs reference 1-1.9 cm). In a multiple regression model, nodule growth at 3 years at an average growth rate over 0.2 mm/year over 3 years since initial evaluation was an independent predictor of longer-term fast nodule growth, even after adjusting for age, biological sex, TSH level, and nodule size (P < 0.001). CONCLUSION: The natural history of benign nodule growth is diverse, with over 80% of nodules demonstrating minimal to no growth long-term. Nearly 20% of cytologically benign nodules may exhibit a fast, continued growth pattern, which can be predicted by the 3-year growth rate pattern. These findings can help inform decision making for tailored benign nodule follow-up and monitoring.

Radiofrequency Ablation for Benign Thyroid Nodules.

CONTEXT: Thermal ablative techniques of the thyroid have recently gained clinical traction as a therapeutic alternative that provides symptomatic relief and confers potential advantages over surgery. A truly multidisciplinary technique, thyroid ablation is currently performed by endocrinologists, interventional radiologists, otolaryngologists, and endocrine surgeons. Radiofrequency ablation (RFA), specifically, has seen widespread adoption, particularly in the treatment of benign thyroid nodules. This review summarizes current evidence on the application of RFA in benign thyroid nodules, and provides a start to finish overview of procedural preparation, performance, and outcomes. EVIDENCE ACQUISITION: A narrative review of literature focusing on RFA in the treatment of benign nodular disease was performed. Emphasis was placed on consensus statements, best practice guidelines, multi-institutional studies, and systematic reviews to summarize key concepts in candidacy, techniques, expectations, and outcomes. FINDINGS: RFA is increasingly recognized as a first-line treatment strategy in the management of symptomatic nonfunctional benign thyroid nodules. It can also be considered in functional thyroid nodules with small volumes or in patients ineligible for surgery. A targeted and efficacious technique, RFA results in gradual volume reduction that preserves the function of the surrounding thyroid parenchyma. Proper procedural technique, proficiency in ultrasound, and experience in ultrasound-guided procedures are instrumental to maintaining low complication rates and achieving successful ablation outcomes. CONCLUSIONS: In pursuit of a personalized approach, physicians across disciplines are increasingly incorporating RFA into their treatment algorithms, most commonly for benign nodules. As with any intervention, thoughtful selection and implementation ensure a safe procedure with optimal patient benefit.

Radiofrequency ablation for benign thyroid nodule treatment: New solution in our center.

INTRODUCTION AND IMPORTANCE: Thyroid nodules are one of the most common thyroid disorders and are estimated at 4-7 % in the general population. Although it is estimated that 95 % of thyroid nodules are benign and only 4.0-6.5 % malignant, a combined assessment of clinical data, ultrasound imaging, and FNAB is needed to estimate the risk of malignancy. Several minimally invasive nonsurgical modalities have been developed to treat thyroid nodules, including ethanol ablation (EA), laser ablation (LA), microwave ablation (MWA), and radiofrequency ablation (RFA). Since 2006, this method had been used to treat thyroid nodules and reported to have good efficacy and safety for treating benign thyroid nodules and recurrent thyroid cancer. This paper aims to provide the efficacy and safety of the RFA procedure in benign thyroid lesions. CASE PRESENTATIONS: Here we report 34 cases of patients with thyroid nodules who underwent RFA procedures. After the procedure, patients were followed up in the first, third, sixth, and twelfth months. The ratio of decreasing volume in the first, third, sixth, and twelfth months was as follows 81.6 %; 76.89 %; 63.48 %, 60.11 %. CLINICAL DISCUSSION: Factors that are thought to predict RFA response include small volume nodule (<12 ml), the presence of a fluid component and well-defined margins, the absence of vascularization, and nonfunctioning status. However, RFA has several limitations, including the procedure that is highly operator dependent to maximize its efficacy, the possibility of persistent lesions, and the lack of a final histological diagnosis that does not completely exclude aggressive histological variants. CONCLUSION: The RFA procedure has minimal side effects, is highly effective, and is short in procedure time.

SFE-AFCE-SFMN 2022 Consensus on the management of thyroid nodules : Follow-up: How and how long?

The SFE-AFCE-SFMN 2022 consensus deals with the management of thyroid nodules, a condition that is a frequent reason for consultation in endocrinology. In more than 90% of cases, patients are euthyroid, with benign non-progressive nodules that do not warrant specific treatment. The clinician's objective is to detect malignant thyroid nodules at risk of recurrence and death, toxic nodules responsible for hyperthyroidism or compressive nodules warranting treatment. The diagnosis and treatment of thyroid nodules requires close collaboration between endocrinologists, nuclear medicine physicians, surgeons, and other specialists. Therefore, this consensus statement was established jointly by 3 societies: the French Society of Endocrinology (SFE), French Association of Endocrine Surgery (AFCE) and French Society of Nuclear Medicine (SFMN); the various working groups included experts from other specialties (pathologists, radiologists, pediatricians, biologists, etc.). This section deals with the follow-up of thyroid nodules, low-grade tumors and microcarcinomas.

Cancer rate of Bethesda category II thyroid nodules.

Aim Thyroid nodules are very common and may be found in more than 50% of the population. Fine-needle aspiration cytology (FNAC) of thyroid nodules is a very useful diagnostic tool with high sensitivity and predictive value for diagnosis. The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) uses six categories for thyroid cytology reporting (I-nondiagnostic, IIbenign, III-atypia of undetermined significance (AUS)/ follicular lesion of undetermined significance (FLUS), IV-follicular neoplasm/suspicious for follicular neoplasm (SFN), V-suspicious for malignancy, and VI-malignant. Our objective was to determine the malignancy rate in Bethesda II nodules. Methods From June 2010 to May 2020 a retrospective analysis was performed among 1166 patients who underwent thyroid surgery for benign thyroid diseases in our institution. Thyroid cytopathological slides and Ultrasound (US) reports were reviewed and classified according to the BSRTC. Data collected included age, gender, cytological features, and histological type of thyroid cancer. Results During the study period, 44.77% (522/1166) of patients with an FNA categorized as Bethesda II underwent thyroid surgery. Incidental malignancy was found in 1.53% (8/522) cases of Bethesda II. The most common malignant tumour type was papillary thyroid carcinoma. Conclusion The current study demonstrates that incidental thyroid carcinoma can be diagnosed after thyroidectomy even in patients with an FNA categorized as Bethesda II.

Clinical, pathological and radiologic features of minute pulmonary meningothelial-like nodules.

OBJECTIVES: Reports about the radiologic features of minute pulmonary meningothelial-like nodules are sparse. This study aims to investigate the radiologic features of minute pulmonary meningothelial-like nodules. METHOD: From January 2016 to April 2019, 7589 patients underwent pulmonary resections at Fudan University Shanghai Cancer Center. Postoperative pathology records were reviewed retrospectively. Fifty-nine patients with minute pulmonary meningothelial-like nodule were included. The identification of minute pulmonary meningothelial-like nodules in pathology specimen included pathologically confirmed in resected nodules, and discovery in the peripheral tissue of other resected nodules incidentally. We went back and checked all the pre-operative scans of patients to analyze surgical decision and observe any change of visible minute pulmonary meningothelial-like nodule over time. Clinic, radiologic and pathological features were collected. RESULT: Fifty-nine patients included 10 men and 49 women, with a mean age of 57.7. Five patients had history, while 54 patients were non-smokers. 79 min pulmonary meningothelial-like nodules was found. Of them, 36 nodules were not visible on computed tomography scan. 43 nodules were visible on computed tomography scan, with an average size of 5.3 mm in 29 patients. Computed tomography appearance included pure ground-glass opacity in 36, mixed in 2, and solid nodules in 5. Nearly half of patients had a pre-operative follow-up more than 6 months (13/29, 44.8%). The median pre-operative radiologic follow-up was 4.9 months. Approximately 90% of patients underwent pulmonary surgery because of other malignant nodule on chest computed tomography scan (52/59, 88.1%). CONCLUSION: Most minute pulmonary meningothelial-like nodules tend to present as ground-glass opacity, especially pure ground-glass opacity. Continuous computed tomography monitoring revealed no radiologic change over time. Continuous computed tomography monitoring was necessary part of management of minute pulmonary meningothelial-like nodule.

The significance of Hashimoto's thyroiditis for postoperative complications of thyroid surgery: a systematic review and meta-analysis.

INTRODUCTION: Hashimoto's thyroiditis (HT) is one of the most common immune-mediated diseases. It makes thyroid surgery more complicated and difficult because there may be adhesions between the thyroid gland and surrounding structures. However, it is still controversial whether HT patients carry a high risk for postoperative complications of thyroid surgery. The purpose of this study was to investigate the significance of HT for the postoperative complications of thyroid surgery. METHODS: A search for studies assessing the postoperative complication risks of HT patients compared with that of patients with benign nodules (BNs) was performed in PubMed, EMBASE and Web of Science. Nine studies (20,118 cases, 1,582 cases of HT and 18,536 cases of BN) were identified, and the data from the relevant outcomes were extracted and analysed. RESULTS: There were no significant differences between the HT group and BN group in recurrent laryngeal nerve palsy (RLNP) and permanent hypoparathyroidism (PHP). The rate of transient hypocalcaemia (THC) was significantly higher in the HT group (16.85%) than in the BN group (13.20%). CONCLUSIONS: The meta-analysis showed that HT only increased the risk of the postoperative complication THC compared to BN. Understanding the significance of HT in postoperative hypoparathyroidism after thyroid surgery would help clinicians perform sufficient preoperative (and postoperative) assessments and to optimise surgical planning.

Clinical and functional results of radiofrequency ablation and microwave ablation in patients with benign thyroid nodules.

OBJECTIVES: To determine how well ultrasound-guidance percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA) performed for benign symptomatic thyroid nodules in terms of clinical and functional outcomes. METHODS: Patients who had a thyroid nodule-linked symptoms acting as dysphagia, cosmetic issues, pain, a foreign body sense, hyperthyroidism secondary to autonomous nodules, or concern of malignancy were involved in the study. The primary was the comparison in symptom scores obtained at 1, 3, and 6 months after RFA and MWA. The volume alterations in nodules and alterations in thyroid gland functions were secondary objectives. RESULTS: This prospective study carried out from November 2014 and January 2017 at the General Surgery Department, Marmara University, Faculty of Medicine, Istanbul, Turkey included a total of 100 nodules (50% MWA, 50% RFA). There were statistically significance in pain scores, dysphagia scores, and foreign body sensation scores at 1, 3, and 6 months after therapy in both ablation groups (p=0.0006, p=00004, p=0.0005). At the same time, there were statistically significant reductions in size and volume of the nodules for RFA and MWA (p=0.0004, p=0.0003). There was no significant difference between the RFA and MWA groups' cosmetic scoring and volume changes (p=0.68, p=0.43). CONCLUSIONS: Alternative therapies for benign symptomatic thyroid nodules include RFA and MWA. The findings of this research revealed that both approaches are safe and effective.

Urinary biomarkers of phthalates exposure and risks of thyroid cancer and benign nodule.

Phthalates have been reported to affect the function and growth of thyroid. However, there is little data on the effect of phthalates on thyroid oncogenesis. Here we explored the associations between phthalates exposure and the risks of thyroid cancer and benign nodule. We sex-matched 144 thyroid cancer, 138 benign nodule patients and 144 healthy adults from Wuhan, China. Eight phthalate metabolites in spot urine samples were quantified using high-performance liquid chromatography and tandem mass spectrometry. The associations of creatinine-corrected urinary phthalate metabolites with the risks of thyroid cancer and benign nodule were assessed using multivariable logistic regression models. We found that urinary monomethyl phthalate (MMP), mono(2-ethyl-5hydroxyhexyl) phthalate (MEHHP) and mono(2-ethylhexyl) phthalate (MEHP) associated with increased risks of thyroid cancer and nodule, with adjusted odds ratios (ORs) ranging from 1.74 to 4.78 comparing the extreme tertiles, and urinary monobutyl phthalate (MBP) was associated with decreased risks of thyroid cancer and benign nodule (all P for trends < 0.05). Male-specific positive associations of urinary monoethyl phthalate (MEP) with thyroid cancer and nodule as well as urinary mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) with thyroid cancer were also observed. Our results suggest that exposure to certain phthalates may contribute to increased risks of thyroid cancer and benign nodule.

Programmed death-ligand 1 overexpression is a prognostic marker for aggressive papillary thyroid cancer and its variants.

Programmed death-ligand 1(PD-L1) expression on tumor cells is emerging as a potential predictive biomarker in anti-PD-L1 directed cancer immunotherapy. We analyzed PD-L1 expression in papillary thyroid carcinoma (PTC) and its variants and determined its prognostic potential to predict clinical outcome in these patients. This study was conducted at an academic oncology hospital which is a prime referral centre for thyroid diseases. Immunohistochemical subcellular localization (IHC) analyses of PD-L1 protein was retrospectively performed on 251 archived formalin fixed and paraffin embedded (FFPE) surgical tissues (66 benign thyroid nodules and 185 PTCs) using a rabbit monoclonal anti-PD-L1 antibody (E1L3N, Cell Signaling Technology) and detected using VECTASTAIN rapid protocol with diaminobenzidine (DAB) as the chromogen. The clinical-pathological factors and disease outcome over 190 months were assessed; immunohistochemical subcellular localization of PD-L1 was correlated with disease free survival (DFS) using Kaplan Meier survival and Cox multivariate regression analysis. Increased PD-L1 immunostaining was predominantly localized in cytoplasm and occasionally in plasma membrane of tumor cells. Among all combined stages of PTC, patients with increased PD-L1 membrane or cytoplasmic positivity had significantly shorter median DFS (36 months and 49 months respectively) as compared to those with PD-L1 negative tumors (DFS, both 186 months with p < 0.001 and p < 0.01 respectively). Comparison of PD-L1+ and PD-L1- patients with matched staging showed increased cytoplasmic positivity in all four stages of PTC that correlated with a greater risk of recurrence and a poor prognosis, but increased membrane positivity significantly correlated with a greater risk of metastasis or death only in Stage IV patients. In conclusion, PD-L1 positive expression in PTC correlates with a greater risk of recurrence and shortened disease free survival supporting its potential application as a prognostic marker for PTC.

The McGill Thyroid Nodule Score's (MTNS+) role in the investigation of thyroid nodules with benign ultrasound guided fine needle aspiration biopsies: a retrospective review.

BACKGROUND: Ultrasound guided fine needle aspiration (USFNA) biopsies of thyroid nodules sometimes create a decision-making dilemma for surgeons as they may yield falsely benign results. The McGill Thyroid Nodule Score + (MTNS+) was developed to aid in clinical guidance regarding the management of patients with these USFNA results. The aim of this study was to assess the MTNS+ as a clinical tool in patients with benign preoperative thyroid nodule USFNAs and to analyze the relationship between nodule size and malignancy in these patients. METHODS: We conducted a retrospective chart review of 1312 patients who underwent thyroidectomies between 2010 and 2015 at the McGill University Teaching Hospitals. Patients with Bethesda II (benign) USFNA results, calculated MTNS+, and nodule size evaluated on ultrasound were included in the study. The false-negative rate was calculated, and MTNS+ and nodule size were each compared to final pathology results. Binary logistic regression was used for statistical analysis. RESULTS: Of the 1312 patients, 101 met the inclusion criteria and together had an average MTNS+ score of 6.83, which corresponds to a predicted malignancy rate between 25 and 33 %. Final pathology revealed malignancy in 16 (15.8 %) subjects. The average MTNS+ of patients with malignant nodules on surgical pathology was 8.25, while that of patients with benign nodules was 6.56. Patients with nodule size 1-1.9 cm (a) and 2-2.9 cm (b) each had an equal rate of malignancy of 2.97 % (n = 3), nodule size 3-3.9 cm (c) had a rate of 1.98 % (n = 2), and nodule size ≥4 cm (d) a rate of 7.92 % (n = 8). CONCLUSION: The rate of malignancy (15.8 %) is higher than expected when reviewing the risk of malignancy in nodules considered as Bethesda class 2. On the other hand, the rate is lower than the 25-33 % predicted by the MTNS+. We also found a higher malignancy rate for nodules above 4 cm in size, but size was a poor predictor of malignancy when used alone. Therefore, while the MTNS+ may be helpful at helping to identify USFNAs that are incorrectly classified as benign, the percentage risk of malignancy is lower than expected.

Predictive factors for benign lesions in partially or radically resected kidneys in a single independent cancer center.

OBJECTIVE: To assess the incidence and predictive factors of benign renal lesions in surgical specimens obtained at our institution. METHODS: We carried out a retrospective assessment of 96 renal nodules, diagnosed by dynamic multi-detector row helical computed tomography, and resected by either radical or partial nephrectomy between January 2004 and November 2011. The incidence of benign lesions in 1-cm increments of diameter was determined and the predictive factors for these lesions were then evaluated. RESULTS: Of the 96 nodules, histology confirmed that 13 (13.5%) were benign. The incidence of benign lesions was 25.0% for nodules <1 cm, 23.8% for nodules 1-1.9 cm, 11.5% for nodules 2-2.9 cm, 7.7% for nodules 3-3.9 cm, and 7.1% for nodules ≥4 cm. Multivariate analysis showed that younger age (<60 years; odds ratio [OR] = 5.23), female gender (OR = 4.78), and smaller nodule size (<3 cm; OR = 6.14) were significant predictive factors for benign lesions. CONCLUSIONS: The incidence of benign lesions in this study (13.5% of total cases) was relatively low compared with recent studies from Western countries that reported an incidence of 15-20%. Significant predictive factors for benign lesions included younger age, female gender, and smaller tumor size.