Thyroid nodules represent one of the most prevalent endocrine abnormalities in clinical practice, with a palpation frequency of roughly 4–7% in the general population and up to 50–60% when identified accidentally using ultrasonography. A single thyroid nodule (STN) is characterized as a distinct enlargement within a thyroid gland that is otherwise non-palpable. While most of these nodules are benign, the primary clinical concern is to rule out malignancy, which occurs in a considerable percentage of patients [1, 2].

The incidence of cancer in solitary thyroid nodules ranges from 10% to 30%, influenced by demographic and regional factors. Thyroid cancers are the most prevalent endocrine malignancies, with papillary carcinoma being the primary histological form, succeeded by follicular, medullary, and anaplastic carcinomas. Timely diagnosis is crucial, as the prognosis for most differentiated thyroid malignancies is excellent when identified and managed promptly [3, 4].

The assessment of an isolated thyroid nodule entails a synthesis of clinical evaluation, thyroid function tests, imaging studies, and cytological examination. High-resolution ultrasonography (USG) is essential for detecting suspicious characteristics, including hypoechogenicity, microcalcifications, uneven edges, and heightened vascularity. Nonetheless, fine-needle aspiration cytology (FNAC) continues to be the fundamental examination for distinguishing benign from malignant nodules owing to its simplicity, cost-effectiveness, and high diagnostic precision [5, 6].

Notwithstanding advancements in diagnostic techniques, preoperative differentiation between benign and malignant nodules continues to pose a therapeutic barrier. Histopathological examination (HPE) is the final diagnostic gold standard. The pattern and prevalence of malignancy in solitary thyroid nodules may differ across various geographies and healthcare environments, requiring institution-specific investigations [7].

This study aimed to assess the clinical characteristics, cytological results, and histological patterns of malignant thyroid tumors manifesting as solitary nodules in patients at a tertiary referral center. The study seeks to evaluate the diagnostic efficacy of FNAC in identifying cancer in solitary thyroid nodules

This prospective observational study was carried out in the Department of General Surgery at a tertiary referral center over a duration of August 2022 to July 2023, Forty participants with clinically identified solitary thyroid nodules were enrolled in the trial following the acquisition of informed permission. Ethical approval was secured from the Institutional Ethics Committee before the initiation of the project. All patients had comprehensive clinical assessment, encompassing history taking and physical examination.

Inclusion Criteria

• Patients aged ≥18 years presenting with a clinically solitary thyroid nodule
• Patients willing to undergo diagnostic evaluation and surgical management
• Patients who provided written informed consent

Exclusion Criteria

• Patients with multinodular goiter or diffuse thyroid enlargement
• Patients with previously diagnosed thyroid malignancy
• Patients who had undergone prior thyroid surgery
• Patients with serious comorbid conditions unfit for surgery
• Patients unwilling to participate in the study

Statistical Analysis

Data were inputted into Microsoft Excel and evaluated with statistical tools. Descriptive data were presented as mean, standard deviation, frequencies, and percentages. The diagnostic efficacy of FNAC was assessed by determining sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy, with histology as the reference standard. The correlation between clinical/ultrasonographic characteristics and malignancy was evaluated using the Chi-square test or Fisher’s exact test, with a p-value <0.05 deemed statistically significant

This study investigated 40 patients with solitary thyroid nodules. All patients received clinical evaluation, ultrasonography (USG), fine-needle aspiration cytology (FNAC), and subsequent histological examination (HPE). The results are encapsulated here.

Table 1: Age and Gender Distribution of Patients

The predominant age group of patients was 41–50 years (30%), succeeded by the 31–40 years group (25%). A pronounced female predominance (75%) was noted, with a female-to-male ratio of 3:1, signifying a greater prevalence of solitary thyroid nodules in females.

Table 2: Clinical Presentation of Patients

All patients exhibited neck swelling (100%), which was the predominant complaint. Compressive symptoms, including dysphagia (12.5%) and hoarseness (7.5%), were few yet clinically significant, particularly in instances subsequently verified as malignant.

Table 3: Ultrasonographic (USG) Features of Thyroid Nodules

Ultrasonographic assessment indicated that hypoechogenicity (83.3%), uneven margins (75%), and microcalcifications (66.7%) were significantly correlated with malignant nodules. Solid composition was observed in the majority of malignant cases (91.7%), underscoring its significance as a concerning characteristic.

Table 4: FNAC Findings and Correlation with Histopathology

FNAC classified the majority of nodules as benign (62.5%). The majority of malignant patients verified by histology were either classified as malignant or suspicious on FNAC. A limited number of false-negative and false-positive instances were noted, underscoring the necessity for histological validation.

Table 5: Histopathological Types of Malignant Thyroid Tumors

Among malignant thyroid neoplasms, papillary carcinoma was the predominant type (75%), succeeded by follicular carcinoma (16.7%) and medullary carcinoma (8.3%). This distribution aligns with the established epidemiology of thyroid cancers.

Solitary thyroid nodules (STNs) are prevalent clinical occurrences and present a considerable diagnostic challenge owing to the potential for underlying malignancy. This study assessed the clinical, cytological, and histological characteristics of 40 patients with solitary thyroid nodules at a tertiary referral center, emphasizing the identification of malignant lesions [8-10].

The present study indicates that most patients were aged 41–50 years (30%), aligning with prior research that identifies the peak occurrence of thyroid nodules in the third to fifth decades of life. A significant female predominance (75%) was noted, with a female-to-male ratio of 3:1. This conclusion corresponds with existing literature, which ascribes the increased incidence in females to hormonal factors, including the influence of estrogen on thyroid cell proliferation [11-13].

The overall incidence of malignancy in this study was 30%, aligning with the documented range of 10–30% in solitary thyroid nodules. The increased occurrence may be ascribed to the tertiary care environment, where more dubious or referred patients are assessed. Analogous investigations have indicated similar malignancy rates, underscoring the necessity for comprehensive assessment of all solitary thyroid nodules [14-16].

All patients exhibited neck swelling (100%), which was the predominant presenting symptom. Compressive symptoms, including dysphagia (12.5%) and hoarseness of voice (7.5%), were less prevalent but more frequently linked to malignant lesions. The occurrence of cervical lymphadenopathy (10%) in certain patients heightened the suspicion of malignancy, aligning with findings from earlier research [17-19].

Ultrasonography (USG) is essential for assessing thyroid nodules. The current investigation identified a substantial association between malignancy and characteristics including hypoechogenicity (83.3%), uneven margins (75%), and microcalcifications (66.7%). These findings correspond with known sonographic criteria for malignancy risk categorization and have been extensively documented in prior research. The prevalence of solid composition (91.7%) in malignant nodules further underscores its importance as a suspicious characteristic [20, 21].

Fine-needle aspiration cytology (FNAC) demonstrated significant diagnostic utility in this investigation. It exhibited elevated sensitivity and specificity, accurately categorizing the majority of malignant patients as either malignant or suspicious. Nevertheless, some anomalous examples were noted, comprising one false-negative and one false-positive outcome. The discrepancies underscore the limitations of FNAC, especially in distinguishing follicular adenoma from cancer, as capsular or vascular invasion can only be verified histologically [22, 23].

Histopathological examination (HPE) is the definitive diagnostic gold standard. This study identified papillary carcinoma as the predominant malignancy at 75%, succeeded by follicular carcinoma at 16.7% and medullary carcinoma at 8.3%. This distribution aligns with global trends, wherein papillary carcinoma constitutes the predominant form of thyroid cancer and is linked to a positive outcome upon early detection [24].

This study's findings underscore the need of a multimodal approach in assessing solitary thyroid nodules. Although clinical examination and imaging offer significant insights, FNAC functions as a dependable preliminary diagnostic instrument, whereas histology validates the definitive diagnosis. Timely identification and suitable surgical intervention are crucial for enhancing patient outcomes [25, 26].,

This study illustrates that solitary thyroid nodules possess a considerable malignancy risk (30%), highlighting the necessity for meticulous and systematic assessment. A greater incidence was noted among females and the middle-aged demographic. Fine-needle aspiration cytology (FNAC) demonstrated good sensitivity and reliability as an initial diagnostic method, while ultrasonography (USG) offered significant supporting characteristics in malignancy prediction. Nonetheless, histopathology analysis continues to be the benchmark for conclusive diagnosis. Among malignant tumors, papillary carcinoma was the predominant kind, aligning with global trends. Suspicious clinical symptoms and distinctive ultrasonographic findings necessitate rapid surgical intervention.

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