thyroid nodules are relatively widespread involving 4 - 7% of general population ( 1 - 3 ) . these nodules are more common in female gender and their prevalence increases with aging , history of radiotherapy and also goiterogenic regimen intake ( 3 ) . however , it is impossible to distinguish them from malignant nodules in clinical settings . many diagnostic tests such as radionuclide scan , high resolution ultrasound and also biopsy by fna ( fine - needle aspiration ) have been introduced for patients in need for surgical interventions . previous studies have demonstrated that fna biopsy is an exact , cheap and also the simplest diagnostic test for rapid definition of thyroid nodules ( 4 - 6 ) . it has been even shown that fna is associated with higher sensitivity and specificity than frozen section method ( 7 - 9 ) . as a result , fna is making the surgical decision making easier leading to a decrease in unnecessary surgeries for thyroid nodules as well as significant benefits in searching for malignancies of the gland ( 4 , 5 , 10 ) . 
 
 due to cheapness , easiness , accessibility and absence of significant adverse effects , use of fna is increasing resulting in early detection of malignancies in early stages . the defects mostly relates to lack of sample competence , sampling techniques , the pathologist 's expertise and the overlap in cellular characteristics for benignity or malignancy ( 11 - 13 ) . based on some studies , accuracy and sensitivity of this method in determination of thyroid nodules situation has been questioned . having that in mind , we designed this study to assess the patients which were reported as follicular lesions in their preoperative fna and their frozen section evaluation were of other pathologic diagnosis . the conclusions of the study not only can be a basis for future studies , but also may be used in decision making for therapeutic strategies . in this cross - sectional study , records of adult ( above 18 years old ) patients with thyroid nodule referred to surgery or internal medicine clinics of rasoul - e - akram hospital were reviewed , from year 2013 to 2014 . patients ' data including age , gender , duration of nodule appearance , family history of the condition and the primary fna results were gathered . for patients underwent thyroid surgery , frozen section and permanent pathologic results were recorded too . among the cases , the prevalence of follicular adenoma , papillary and follicular carcinoma , hurtle cell adenoma and carcinoma in frozen sections and permanent pathology were obtained . in this study , 42 patients with thyroid nodule were included whose fna results were reported as a follicular lesion . meansd age of patients was 39.3  16.51 years ( range : 9 - 80 years ) . about 67% ( n= 28 ) and 32% ( n= 14 ) of patients were male and female , respectively . location of the lesions in the gland in 20(47.6% ) cases was in the right side ; however left - sided ( 35.7% ) and bilateral ( 16.7% ) lesions were also observed . diagnosis of papillary carcinoma was made for 13 ( 31% ) patients in frozen section . the procedure also defined 25 ( 59.5% ) cases as benign , 3 cases as non - papillary malignancies . results of permanent histology showed that follicular adenoma is the most prevalent lesion which appeared in 25 ( 59.5% ) cases with follicular lesions . after that , papillary and follicular carcinoma were seen in 10 ( 23.8% ) and 4 ( 9.5% ) cases , respectively . hurtle cell pathologies were the least common findings , including adenoma ( 4.8% ) and carcinoma ( 2.4% ) . despite constituting only 1% of human malignancies , thyroidal cancer is the most common endocrine malignancy . the condition is also responsible for the highest mortality in endocrine cancers ( 14 ) . the peak incidence of papillary , follicular and medullary types is in fourth and fifth decades of life and also in seventh and eighths for anaplastic carcinoma ( 15 ) . papillary carcinoma is the most common type of thyroid cancer which typically involves individuals with age between 30 to 40 ; women are more involved than men ( 17 ) . it shows a strong lymphotropic nature having a great tendency to metastasize to lymph nodes and progressing to a multifocal pattern in thyroid gland . the prognosis is excellent with appropriate treatment extending 10 year survival up to 90% ( 18 ) . the present study was designed to compare frequency of papillary cancers in patients with thyroid nodules that were initially detected as follicular lesions by fna . mean age of patients was 39.33 and women were twice as men . 
 
 in a study conducted by herrera et al , clinical presentations and prognostic factors were assessed in 229 mexican patients with ptc ( papillary thyroid carcinoma ) . the mean age was 4216 that is very close to the result of our study . in addition , proportion of women to men was 205 to 24 which is greater than the relation in our patients ( 18 ) . 
 
 in our study based on final histology results , 15 out of 42 patients needed repeated surgery for total thyroidectomy among which 11 patients underwent the surgery based on their frozen section performed durint the first surgery . based on the results of frozen section , in 5 patients whom underwent total thyroidectomy , final pathology did not confirm existence of malignancy . regarding diagnosis of ptc in patients with follicular lesions reported in frozen sections , 13 cases were diagnosed as papillary carcinoma . however , 5 cases were reported as benign lesions eventually . 
 
 according to our data , diagnostic sensitivity of frozen section for detecting papillary carcinoma was 84.4% with a specificity of 80% . , respectively we can conclude that negative reports reported by frozen section for papillary diagnosis is valuable and lobectomy can be performed with certainty based on negative results . callcut et al , in 2004 assessed 102 patients undergoing surgical resection due to follicular neoplasm . mean age in our study was lower but higher frequency of female patients was a common point . in mentioned study , 41 ( 32% ) 5 ( 4% ) and 3 ( 2% ) also were reported as malignant and intermediate . all patients with malignant frozen section result , had malignancy in their final pathologic report . in the study , sensitivity , specificity , positive and negative predictive values were 67% , 100% , 100% and 96% , respectively . 
 
 in another study published by chen et al , 125 patients with the follicular lesions undergoing exploratory surgery were included . in 104 patients frozen section besides , wrong results of frozen section were observed by histology in 6 patients ( 22 ) . in our study , frozen section changed the type of surgery in 16 ( 38% ) cases . according to the , a second surgery was avoided in 11 out of 15 cases ( 73.3% ) . 
 
 in a study by udelsman et al , evaluation of frozen section results in patients with follicular lesions , among 61 patients who had surgery , frozen section was obtained for 29 ones . in the group without frozen section , one patient had undergone the method due to the nodule s appearance which turned out to be follicular carcinoma . malignancy was reported in 1 ( 3.4% ) patient 's frozen section for which total thyroidectomy was performed . histology reported well - differentiated thyroid cancer in 6 ( 21% ) patients in frozen section group and 3 ( 10% ) patients in non - frozen section group . in our study , diagnostic accuracy of frozen section was lower than udelsman 's study . 
 
 in another study performed in 2009 regarding fna cytology and frozen section results in patients with follicular lesions , 210 patients with thyroid nodule and also follicular thyroid neoplasm s that frozen section was obtained for them at the time surgery were included . mean age was 43 years ( from 18 to 76 years ) and 77.6% of participants were female . follicular adenoma and hyperplasia were observed in 181 ( 86.2% ) and 6 ( 2.9% ) cases . in the present study sensitivity , specificity , positive and negative predictive values and accuracy of fna was 13% , 97.3% , 37.5% , 90% and 88.1% , respectively . these were 17.4% , 100% , 100% , 90.8% and 91% for frozen section respectively ( 23 ) . results of the study demonstrated a 73% reduction in second surgery in patients with follicular thyroid lesions . this percentage is differed in different studies and is mostly affected by pathologists and case selection criteria . due to the reduction in reoperation and consequently , adverse effects and costs , obtaining a frozen section at the time of surgery in patients with follicular thyroid lesions is recommended . omid jahangiri in data collection and for constructive criticisms of an earlier version of this paper .
background : fine needle aspiration ( fna ) has led to a decrease in unnecessary surgeries for thyroid 
 nodules . 
 this study was designed to compare diagnostic value of fna and frozen section methods 
 in the follicular lesions . 
 methods : this is a cross - sectional study based on the medical records of 42 patients who were referred 
 to surgery clinic of rasool - e - akram hospital in tehran with complaint of thyroid nodules . all 
 fnas were diagnosed as follicular lesions in pathologic evaluation . all the patients underwent thyroid 
 surgery and their frozen section results were also assessed . finally , diagnostic value of the two 
 tests was compared based on final permanent histologic report . 
 results : forty two patients with follicular thyroid nodules diagnosed with fna were included . 
 during the operation , using frozen sections , diagnosis of papillary carcinoma , non - papillary malignancies , 
 benign lesion and intermediate cytology was made in 13 ( 31% ) , 3 ( 7% ) , 25 ( 59.5% ) , 1 
 ( 2.5% ) patients , respectively . 
 results of permanent histology showed that follicular adenoma is the 
 most prevalent lesion which appeared in 25 ( 59.5% ) cases . 
 papillary and follicular carcinomas were 
 detected in 10 ( 23.8% ) and 4 ( 9.5% ) cases , respectively . 
 conclusion : results of the study demonstrate a 73% reduction in second surgery in patients with 
 follicular thyroid lesions based on intraoperative frozen section results .