TIR3B group contains those nodules with mild/focal nuclear atypia suggestive of papillary carcinoma and therefore considered to be at higher risk of malignancy, especially compared to TIR3A. The real risk of this category is difficult to estimate, with a rate of 20–30% reported in the first works [6,7,8,9], subsequently raised up to higher rates in more recent papers [10,11,12,13,14].

For this reason, the choice of the extent of surgery (HT or TT) in these patients is crucial and under debate.

The last American Thyroid Association (ATA) guidelines in Recommendation 19 [15] said that for patients with a solitary, cytologically indeterminate nodule, HT should be the recommended initial surgical approach, but this tool can be changed to more extent surgery if preset several epidemiological, clinical or sonographic features, and/or molecular testing when performed or patient’s preference. These risk factors include the presence of mutations specific for carcinoma, nodule size > 4 cm, ultrasound high-risk nodule, familiar history of thyroid carcinoma, or history of radiation exposure.

Unfortunately, molecular analyses are not always available and are expensive and this limits the risk analysis usually referred only to other clinical and ultrasound evidence.

The kind of initial surgical intervention should contemplate tumor size, but must also take into account all the risk factors, which are paramount in the choice of the type of treatment. HT can have some advantages, such as the theoretical low risk of surgical complications and the no need for replacement thyroid hormone therapy, and can represent a valid option. However, even in the absence of any other risk factors, it is described as an increased risk of local recurrence and worse overall survival in patients with thyroid nodule sizes between 2 and 4 cm who received HT [16].

In our analysis, most patients (78%) underwent TT; the choice of this surgical approach is supported by the increased rate of malignant thyroid lesions at final diagnosis (48%), compared to previous data available in the literature (20–30%) [6,7,8,9] and similar to a recent meta-analysis [17]. Another reason for the prevalence of TT was the patient’s preference. Some patients prefer a less extensive surgery with the realization that a second operation may be necessary if thyroid cancer is the final diagnosis. Other patients may not want to look at the possibility of a second surgical procedure and choose TT as the first step.

Although, this study was conducted in a referral center for endocrine disease, particularly thyroid diseases, and the availability of a multidisciplinary team dedicated (Thyroid Unit) with a specific attitude toward the diagnosis and the treatment of thyroid cancer. From a surgical point of view, this means a reduced risk of surgical side effects and length of hospitalization. Moreover, in our center, only a few surgeons (three) with high experience in thyroid disease surgery (more than 30 surgical interventions per year) performed thyroidectomy. From a pathologist’s point of view, this might imply a more appropriate classification in the TIR3B group only of thyroid nodules presenting real atypia in the follicular proliferation, with a consequent selection of those patients with a high suspicion of cancer and consequently exclusion of those with low-risk characteristics.

Some points in favor of TT are the treatment of potential multicentric tumors, improved disease-free survival, reduced risk of local recurrence, improved potential detection and elimination by radioiodine treatment of persistent/metastatic disease if indicated, let thyroglobulin measurement as effective, reduced risk of a second surgery.

In our study, there was a significant difference in patients’ age between the two groups. This difference may be explained because the younger patients chose to undergo the HT to have less risk of the necessity of thyroid hormone replacement therapy, considering the longest life expectancy.

Also, the time interval between diagnosis and surgery was significantly different between the two groups and was quite long mainly in HT (48 months). This long interval is due to the long waiting list of our center, where beside thyroid disease also other diseases more aggressive and dangerous are treated by surgeons. Moreover, sometimes it is the patient’s desire to wait and see and post-pone the surgical event.

All patients that received HT and had a subsequent diagnosis of carcinoma performed a contralateral surgery as completion, despite recent guidelines had a more conservative approach recommending reducing overtreatment [15]. However, most of these patients (n = 6) were treated before the year of publication of ATA guidelines, and the remaining three patients shared with the surgeon the intervention.

Regarding the post-surgical complications, the risks related to thyroid surgery clearly depend on several factors, such as the extent of surgery, whether this is the first or second operation, the features of the thyroid disease present, the presence of co-existing comorbidities, and the skills and experience of the surgeon [16, 18]. It should be shareable to perform thyroidectomy surgery in a center and a surgeon with high experience in this disease [19].

In a recent article, Chen et al. demonstrated a similar quality of life between TT and lobectomy in thyroid cancer [20].

In our analysis, no significant difference in surgical complications between TT and HT groups was present, and only one case of transient hypocalcemia was described. Moreover, in the 9 patients that received HT as the first approach and subsequently a second surgical operation, no complications were discovered.

Moreover, also considering the length of hospitalization the two groups are quite similar.

The decision on what is the best surgical treatment to propose to TIR3B patients, although affected by different variables and categories of risk, is both for the surgeon and patient a debated issue [20]. Shared decision-making is fundamental in this situation, taking into right account patients’ own preferences and giving them all the knowledge for the choice.

Our study presents some limitations: first) the retrospective design of the study; second) the relatively low number of patients included, also due to the rarity of the disease studies; third) the potential heterogeneous management of the patients due to the different surgical and clinical approaches during the period of inclusion.

In conclusion, our data showed an increased malignancy rate of TIR3B lesions (48%) than expected. This evidence could influence the surgical choice suggesting a radical approach by TT differently from what is stated by ATA guidelines.

The surgical management of patients with TIR3B thyroid nodules remains controversial. Both HT and TT seem to be adequate approaches with no significant post-surgical complications.