Given the increasing prevalence of thyroid cancer and the lack of research on the clinic pathological evaluation of patients with thyroid cancer at Mazandran University of Medical sciences, it is essential to conduct studies in this area. Such studies that analyze the clinic pathological characteristics of cancers can be a great aid to clinicians in accurately predicting the clinical behavior of the tumor. By understanding the clinic pathological characteristics of a tumor and the prognostic factors associated with it, healthcare professionals can improve the prognosis and response to treatment of cancer patients. This knowledge can help reduce mortality and morbidity, and enable clinicians to make informed decisions about the most effective treatment options based on the predicted outcome. Our study has revealed that thyroid cancer is more prevalent in women than in men, with a female – to – male ratio of 9.6 to 1. This finding has been corroborated by the most articles that have examined the clinic pathological aspects of this cancer, as evidenced by Zahi Abdul Sater's study [
8]. Thus, it is clear that certain types of cancer are more common in certain genders. Also, in the study of Bo Youn Cho et al., 82.9% of thyroid cancer patients were female [
9]. In the study by Uzma Bukheri et al., 82.4% of thyroid cancer patients were female [
10]. This could be attributed to the fact that higher estrogen levels in women are considered a risk factor for thyroid cancer [
11]. Additionally, increased detection of thyroid cancer in women, especially during the reproductive period and early life, could be due to annual gynecologic and obstetric examinations. While the gradual rise in thyroid cancer cases among men may be attributed to increased medical visits in later life [
12]. Additionally, the higher prevalence of thyroid cancer in women compared to men could be due to the difference in the immune editing system and immune tolerance between the two genders [
13]. Numerous studies have been conducted to explore the link between prior thyroid conditions, such as hypothyroidism, hyperthyroidism, multi nodular goiter, thyroid nodule, Hashimoto's and Grave's thyroiditis, and the risk of thyroid cancer. However, the epidemiological evidence regarding this association has been inconclusive [
14]. It has been suggested that thyroid hormones and TSH can directly stimulate tumor growth through surface receptors, estrogen pathways, angiogenesis, and gene expression regulation [
15]. The thyroid gland dysfunction is not only linked to other diseases, such as obesity [
16], diabetes mellitus, and vascular diseases [
17], but it can also increase the risk of cancer. Hypothyroidism is characterized by high levels of TSH, which is a known growth factor for thyroid nodules. The prolonged stimulation of TSH in hypothyroidism may contribute to the development or growth of thyroid carcinoma [
18]. In a study conducted by Zoleika Moazezi et al., which explored the risk factors of thyroid cancer through a case – control study, the prevalence of hypothyroidism among thyroid cancer patients was found to be 30.4% [
19]. Our own study corroborated this finding, with a frequency of 33% for hypothyroidism in the population of thyroid cancer patients. Papillary thyroid cancer is the most common histological variant of thyroid cancer, accounting for 80 – 85% of thyroid cancers. The 10- year survival rate of papillary cancer is more than 90% [
20]. In our study, papillary thyroid cancer was the most common pathological variant of thyroid cancer with a frequency of 85.4%. In the study of Dr.Baqer L arijani et al., papillary thyroid cancer was the most frequent pathological variant of thyroid cancer with a frequency of 79.7% [
21]. The frequency of the papillary variant of thyroid cancer was 92% according to Marco Capezzone et al [
22], 69% according Umesh Jayarajah's study [
23], and 78.8% according to Amani Saleh Hadi's study [
24]. In our study, the most common histological variant of thyroid cancer after PTC was MTC, with a frequency of 5.2%. Marco Capezzone [
22], Baqer Larijani [
21], and most other studies conducted in connection with the clinic pathological evaluation of thyroid cancer have found that the most common pathological variant after PTC was FTC. Awra F.Flemban's research has revealed that the occurrence of MTC is on the rise [
25]. In the United States alone, an estimated 1200 cases of MTC are diagnosed each year [
26]. Despite this, the cause of the increasing prevalence of MTC in certain regions remains unclear [
27]. Small local malignancies to large metastatic malignancies are all clinical manifestations of thyroid cancer [
28]. Thyroid cancer patients who develop distant metastases, particularly differentiated thyroid carcinoma, have a worse chance of survival than thyroid cancer patients who do not [
29]. Organs such the lung, bones, brain, and liver are the most typical locations for distant metastasis in thyroid tumors [
30]. Only 10% of instances of anaplastic thyroid carcinoma are restricted to the thyroid, and about 50% of cases have distant metastases [
31]. Age, high tumor size, vascular invasion, and lymph node involvement are among the characteristics that have been identified as risk factors for distant metastasis [
32]. Our study found that 7.6% of thyroid cancer patients had distant metastases, which is lower than Fiaza A. Qari's study's 11% incidence [
33]. The most frequent site of thyroid carcinoma distant metastasis in our analysis was the lung; this result is consistent with that of Abdul Aziz et al.'s study [
34]. The population of anaplastic tumors in our study had the highest frequency of distant metastasis, followed by the population of medullary malignancies, and there were no occurrences of distant metastasis reported in FTC cases. The highest frequency of distant metastasis was associated with MTC in the study of Baqer Larijani et al., and in this study, the frequency of distant metastasis in the FTC thyroid cancer population was equivalent to 21.2% [
21]. In our study frequency of distant metastasis in male thyroid cancer patients (30%) is more than in female thyroid cancer patients (5.2%). In other words, we can draw the conclusion that men are more likely than women to get severe thyroid malignancies. In contrast to the results of our investigation, the gender ratio in the study of Abdul Aziz et al. was equal [
34] More research is necessary to support this finding. The majority of thyroid tumors that are newly discovered are smaller than 2 cm in size and are most often asymptomatic [
35]. One of the clinico pathological charactristics that was also looked at in our investigation was tumor size. Our findings showed that tumors between 2 and 4 cm in size were the most prevalent, occurring 31.8% of the time (67/212) and that the prevalence of tumors of this size is rising, which is consistent with the results of Ramadani's study [
36]. The incidence of tumors between 2 and 4 cm in size remained constant in the article presented by Kent et al [
37]. Such a finding conflicts what we obtained from our research. One of the charactristics of cancer is the ability of tumor cells to invade nearby tissues [
38]. When reviewing thyroidectomy materials, pathologists should be conversant with three forms of invasion: capsular invasion, vascular invasion for tumor categorization, and extra thyroidal invasion and extension for tumor staging. Currently, the cytological background and tumor tissue shape play a role in how capsular invasion and vascular invasion are used to categorize the kind of tumor [
39]. The majority of thyroid neoplasms that have a follicular form and are encased in a fibrous capsule are actually thought to be slow-growing tumors [
40]. 38.2% (81/212) of the thyroid tumors in our study had capsule involvement. This figure corresponds to 33.5% in Shaza Samargandy's study [
41]. Lymph node involvement in our study refers to tumor infiltration in the cervical lymph nodes removed during thyroidectomy surgery. Lymph node involvement in thyroid malignancies was present in 30.7% (65/212) of the study population. In Izadi's study the prevalence of lymph node involvement in thyroid carcinoma was 21.3% [
42]. This percentage in Samargandy's study was 24.9% [
41].