Incidental thyroid carcinoma in surgically treated multinodular goiter: a retrospective study

Multinodular goiter (MNG) is a common thyroid disorder frequently encountered in clinical practice. Although it is generally considered a benign condition, thyroid carcinoma may occasionally be detected in patients undergoing surgery for MNG. The reported prevalence of malignancy in this setting varies widely across different populations and clinical series. The present study aimed to evaluate the incidence of incidental thyroid carcinoma in patients undergoing surgical treatment for multinodular goiter and to analyze the associated demographic and clinicopathological characteristics.

This retrospective study included patients with a preoperative diagnosis of multinodular goiter who underwent total or partial thyroidectomy between January 2018 and May 2024 at the Department of Medical and Surgical Sciences, University Hospital "Ospedali Riuniti" of Foggia. Clinical, demographic, and pathological data were collected from medical records. Statistical analyses were performed to explore potential associations between patient characteristics and the occurrence of incidental thyroid carcinoma.

A total of 223 patients were included in the study. Incidental thyroid carcinoma was identified in 32 cases, corresponding to an overall incidence of 14.4%. Among these patients, 24 were female (75%) and 8 were male (25%), with a female-to-male ratio of 3:1. The incidence of carcinoma was 13.3% in female patients and 19% in male patients, although this difference did not reach statistical significance (χ ² = 0.929; p = 0.335). Papillary thyroid carcinoma represented the most common histological subtype, accounting for 78.1% of cases. Patients diagnosed with carcinoma were significantly younger than those without malignancy (mean age 49.4 ± 16.7 vs. 56.2 ± 13.1 years; p = 0.008). Logistic regression analysis showed that increasing age was associated with a progressive reduction in the probability of malignancy (OR=0.963; p = 0.009).

Incidental thyroid carcinoma represents a relatively frequent finding in patients undergoing surgery for multinodular goiter. Papillary carcinoma is the predominant histological subtype, and no significant sex-related differences were observed. Although variables such as age and thyroid weight may contribute to risk stratification, the current evidence remains insufficient to support modifications to existing screening strategies for thyroid nodules.

This article was retrospectively registered on the 10th of April 2025. The UIN for ClinicalTrial.gov Protocol Registration and Results System is: NCT06924242 for the Organization UFoggia (https://clinicaltrials.gov/ct2/show/NCT06924242).