Parotid incidentalomas: a systematic review

Incidentally found parotid gland lesion in 18F-FDG PET/CT for staging evaluation of patients with hepatocellular carcinoma: remote possibility of metastatic tumor or second primary salivary gland malignancy

OBJECTIVES

We primarily aimed to evaluate whether parotid incidental lesion (PIL) in 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for staging evaluation of patients with hepatocellular carcinoma (HCC) would represent a possibility of extrahepatic metastasis or second primary malignancy (SPM). Additionally, we explored the incidence of PIL in HCC patients and examined any associated risk factors.

METHODS

We retrospectively analyzed patients with HCC who underwent 18F-FDG PET/CT at our institution from 2010 to 2022. The pathological findings of PILs in HCC patients were investigated for confirmatory identification of the risk of HCC metastasis or SPM in parotid gland. Healthy controls received 18F-FDG PET/CT for health screening were also enrolled to compare the incidence of PILs with HCC patients. Various parameters associated with patient demographics and characteristics of HCC were analyzed to find the related factors of PILs.

RESULTS

A total of 17,674 patients with HCC and 2,090 healthy individuals who had undergone 18F-FDG PET/CT scans were enrolled in the analyses. Among the 54 HCC patients who underwent pathological confirmation for PILs, benign primary parotid tumor was most commonly observed (n = 43 [79.6%]); however, no malignant lesions were detected, including HCC metastasis. The incidence of PILs was higher in patients diagnosed with HCC compared with the control group (485 [2.7%] vs. 23 [1.1%], p = 0.002). Analysis for the risk factors for PILs revealed that patient age, sex, and positive viral markers were significantly associated with the incidence of PILs in patients with HCC (all p < 0.001).

CONCLUSIONS

Our study demonstrates that PILs are more frequently identified in patients with HCC on 18F-FDG PET/CT. However, no malignant PIL, including extrahepatic metastasis of HCC, was identified. Therefore, the presence of PIL should not impede or delay the treatment process for patients with HCC. Additionally, we suggested that for future swift and straightforward differential diagnoses of PIL, the development of additional protocols within the PET/CT imaging could be beneficial.

Frequency and malignancy rate of incidental focal salivary gland lesions identified by 18F-fluorodeoxyglucose-positron emission tomography

PURPOSE

We aimed to evaluate the frequency and malignancy rate of incidental salivary gland lesions (ISGLs) in patients undergoing 18F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT).

METHODS

Using a predefined algorithm, all descriptions of FDG-PET/CT scans performed in the North Denmark Region at the Department of Nuclear Medicine, Aalborg University Hospital from 1.12 2009 to 31.12 2019 were electronically searched for focal uptake in one or more salivary glands.

RESULTS

In total, 28,362 FDG-PET/CT scans were performed in the study period. ISGLs were found in 197 (0.7%). A total of 193 (98%) had parotid gland ISGL, and four (2%) had submandibular ISGL. No sublingual lesions were found. Ultimately, 117 patients (60%) were referred to the Department of Otorhinolaryngology-Head and Neck Surgery for evaluation. Fine needle aspiration biopsy was performed in 97 patients, and the most frequent cytopathology was Warthin's tumour (n = 62). Two patients had verified malignancy: one with histopathologically proven acinic cell carcinoma and one with cytopathologically proven metastasis from an oral squamous cell carcinoma.

CONCLUSIONS

Incidental salivary gland findings on FDG-PET/CT are rare, and the risk of malignancy is low. Patients with ISGL may be evaluated secondary to the primary disease, but special attention should be given to patients with prior or known head-and-neck malignancies and patients with symptoms from the salivary glands, including swelling.

Association of Ultrasonography With Final Histopathology in Diagnosing Thyroid Malignancy: A Single-Institute Retrospective Study

Background Thyroid nodules are well-defined regions of aberrant echogenicity within the thyroid parenchyma that are radiologically distinct from the normal thyroid gland. The most common incidental finding in imaging scans that include the neck is a thyroid nodule. Rarely are thyroid nodules cancerous, as the majority are benign. Aim The current study aims to assess the concordance between ultrasound (US) of thyroid nodules and final histopathology results to identify the different types of detected thyroid lesions. Methodology A retrospective study reviewed the medical files of all patients presenting to the Armed Forces Hospital, Southern Region, with suspected thyroid nodules from April 2018 to January 2020. Data were extracted using pre-structured proforma to avoid inconsistency. Data extracted included patient demographic, swelling laterality, size, and US and histopathological findings. Results In the present study, 47 samples had a mean age of 44.27 (SD = ±13.5) years, 85.1% were of the female gender, the majority (85.1%) had multiple nodules, 38.3% were with Thyroid Imaging Reporting and Data System (TI-RADS) TR4 US score, and the median size of the nodule on US was 3 cm with a range of 0.6 to 14 cm. The study showed that 10% of TR1 samples were lymphocytic in histopathology, 66.7% of TR3 samples were benign multinodular goiter in histopathology, and 55.6% of samples of TR4 were malignant in histopathology. Conclusions The current study showed that the malignancy rate of the examined nodules was not uncommon both by US and histopathology, where papillary carcinoma was the most detected malignancy. The study showed a satisfactory agreement rate between TI-RADS classification by US sonography and histopathological reporting, where TR4 and TR5 by the US were mainly categorized as pre-malignant/malignant lesions by histopathology.