Cross-sectional Imaging of Parotid Gland Nodules: A Brief Practical Guide

Adenoid cystic carcinoma of head and neck: Summary and review of imaging findings

Purpose

Current reports of adenoid cystic carcinoma of the head and neck (ACC) are all case reports, and there is no basilar summary of its imaging findings. This study aims to summarise ACC's computed tomography (CT) and magnetic resonance imaging (MRI) findings to improve radiologists' knowledge of this disease.

Methods

We collected clinical and imaging data of patients with ACC during the last decade, and two radiologists retrospectively analysed the imaging characteristics.

Results

Of the 16 patients included, six were able to self-perceive bulkiness, and 11 had regional pain. Tumour morphology was regular in six cases, with clear borders in 11 cases, invasion of the surrounding bony mass in 12 cases, and invasion of peripheral nerves in 15 cases. CT mostly shows an irregular soft-tissue density mass with mild-to-moderate enhancement after contrast medium administration. On MRI, the ACC showed isointense or hypointense signals on T1-weighted images (T1WI) and hyperintense or slightly hyperintense signals on T2-weighted images (T2WI). All signals were markedly enhanced after gadolinium enhancement.

Conclusions

ACC often has an irregular morphology, sometimes with a cystic component, enhancement on enhancement scans, easy destruction of adjacent bone, and invasion of peripheral nerves. The diagnosis should be considered when these features are encountered in clinical practice.

Post-operative Diagnosis of Primary Parotid Tuberculosis in a Patient Initially Diagnosed as Benign Pleomorphic Adenoma

Primary parotid tuberculosis is a well-known but extremely rare entity even in endemic countries. Most of the cases are diagnosed late in the course of illness when the parotid shows features of cold abscess leading to facial disfigurement. Early diagnosis is a clinical challenge due to lack of clinical suspicion as well as absence of clinical or radiological tests suggestive of the disease. Fine needle aspiration cytology features of early tuberculosis can easily be confused with a pleomorphic adenoma. When ultrasound examination of a parotid lesion is atypical, image guided core needle biopsy can be helpful in differentiating these kinds of rare diseases from more common parotid pathologies.

Point‐of‐care ultrasound scan as the primary modality for evaluating parotid tumors

Objectives

This study aimed to explore ultrasonography as a single imaging modality for the initial assessment of parotid lesions compared to computed tomography (CT) and magnetic resonance imaging (MRI).

Methods

A retrospective cross‐sectional study was performed on 264 parotid gland lesions evaluated in a dedicated point‐of‐care ultrasound (POCUS) clinic with concurrent fine needle biopsy (FNB). Two hundred and nine of these lesions also underwent CT or MRI imaging. Histopathology results, when available, were recorded and compared to imaging impressions.

Results

Surgeon‐performed POCUS classified parotid masses accurately when compared to final histopathology (90/96, 94%). Using predefined criteria, POCUS determined the nature of parotid lesions more definitively than the descriptive CT or MRI radiology reports (p <.001). Sub‐analysis showed that ultrasonography was able to distinguish between benign pathologies with high degree of accuracy (Warthin tumor—82%, pleomorphic adenoma—64%).

Conclusions

POCUS can accurately distinguish between benign and malignant parotid lesions. POCUS may suffice as the only imaging study for benign lesions, obviating the need for additional cross‐sectional imaging. This can be combined with fine needle or core biopsy in the same visit, resulting in expedient diagnosis, low cost, and lack of radiation exposure.

Level of Evidence

2b, individual cross‐sectional cohort study.

An approach to evaluate the quality of radiological reports in Head and Neck cancer loco-regional staging: experience of two Academic Hospitals

OBJECTIVES

To evaluate the quality of the reports of loco-regional staging computed tomography (CT) or magnetic resonance imaging (MRI) in head and neck (H&N) cancer.

METHODS

Consecutive reports of staging CT and MRI of all H&N cancer cases from 2018 to 2020 were collected. We created lists of quality indicators for tumor (T) for each district and for node (N). We marked these as 0 or 1 in the report calculating a report score (RS) and a maximum sum (MS) of each list. Two radiologists and two otolaryngologists in consensus classified reports as low quality (LQ) if the RS fell in the percentage range 0-59% of MS and as high quality (HQ) if it fell in the range 60-100%, annotating technique and district. We evaluated the distribution of reports in these categories.

RESULTS

Two hundred thirty-seven reports (97 CT and 140 MRI) of 95 oral cavity, 52 laryngeal, 47 oropharyngeal, 19 hypo-pharyngeal, 14 parotid, and 10 nasopharyngeal cancers were included. Sixty-six percent of all the reports were LQ for T, 66% out of all the MRI reports, and 65% out of all CT reports were LQ. Eight-five percent of reports were HQ for N, 85% out of all the MRI reports, and 82% out of all CT reports were HQ. Reports of oral cavity, oro-nasopharynx, and parotid were LQ, respectively, in 76%, 73%, 100% and 92 out of cases.

CONCLUSION

Reports of staging CT/MRI in H&N cancer were LQ for T description and HQ for N description.

[Performance of the magnetic resonance imaging in parotid gland tumor histopathology]

Introduction

salivary gland tumors mainly occur in the parotid gland. These tumors are rare but are characterized by histological heterogeneity, thus posing diagnostic challenges. Magnetic resonance imaging (MRI) is currently the most reliable imaging test for the evaluation of these tumors. The purpose of this study was to highlight the diagnostic value of MRI and its role in parotid gland tumor histopathology.

Methods

we conducted a retrospective descriptive and analytical study of 50 patients with parotid gland tumor, operated and treated in the ear, nose and throat (ENT) Department and in the Department of cervicofacial surgery at the Tahar Sfar University Hospital of Mahdia between 2001 and 2019. All patients underwent preoperative MRI of the parotid gland.

Results

out of 50 patients included in the study, 36 (72%) had benign tumor and 14 (28%) malignant tumor. The sensitivity of MRI for the diagnosis of malignant tumor was 92.8% with a specificity of 97.2%, a negative predictive value of 93% and a positive predictive value of 97%. With respect to benign tumor characterization, MRI suggested the diagnosis of Warthin tumor in all cases (13 cases) and of pleomorphic adenoma in 22 out of 23 cases. There were two diagnostic errors: MRI suggested the diagnosis of pleomorphic adenoma instead of adenoid cystic carcinoma in one case and of malignant tumor instead of pleomorphic adenoma due to diffusion restriction.

Conclusion

MRI is highly efficient in the assessment of parotid tumor histology and, especially, after the advent of new functional sequences. However, only histological examination allows to confirm with certainty the diagnosis.

Ultrasound and Bioptic Investigation of Patients with Primary Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is a chronic and heterogeneous disorder characterized by a wide spectrum of glandular and extra-glandular features. The hallmark of pSS is considered to be the immune-mediated involvement of the exocrine glands and B-cell hyperactivation. This leads pSS patients to an increased risk of developing lymphoproliferative diseases, and persistent (>2 months) major salivary gland enlargement is a well-known clinical sign of possible involvement by B cell lymphoma. Better stratification of the patients may improve understanding of the mechanism underlying the risk of lymphoproliferative disorder. Here, we summarize the role of different imaging techniques and a bioptic approach in pSS patients, focusing mainly on the role of salivary gland ultrasonography (SGUS) and a US-guided core needle biopsy (Us-guided CNB) as diagnostic and prognostic tools in pSS patients with persistent parotid swelling.

Narrative review of multiparametric ultrasound in parotid gland evaluation

Disorders affecting parotid gland represent a heterogeneous group comprising congenital, inflammatory and neoplastic diseases which show a focal or diffuse pattern of appearance. The differentiation of neoplastic from non-neoplastic conditions of parotid glands is pivotal for the diagnostic imaging. Frequently there is evidence of overlapping between the clinical and the imaging appearance of the various pathologies. The parotid gland is also often object of study with the combination of different techniques [ultrasound-computed tomography-magnetic resonance imaging (US-CT-MRI), ex.]. Compared to other dominant methods of medical imaging, US has several advantages providing images in real-time at lower cost, and without harmful use of ionizing radiation and of contrast enhancement. B-mode US, and the microvascular pattern color Doppler are usually used as first step evaluation of parotid lesions. Elastography and contrast-enhanced US (CEUS) has opened further possible perspectives to improve the differentiation between benign and malignant parotid lesions. The characterization of the parotid tumors plays a crucial role for their treatment planning and for the prediction of possible surgical complications. We present, here an updated review of the most recurrent pathologies of parotid gland focusing on the diagnostic power of multiparametric US including CEUS and ultrasound elastography (USE); limitations, advantages and the main key-points will be presented.

Diagnostic value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in sublingual and submandibular salivary gland tumors

The aim of the present study was to compare the diagnostic accuracy of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) with that of conventional imaging studies (CIS), such as CT or magnetic resonance imaging (MRI), in the clinical diagnosis and staging of submandibular and sublingual salivary gland tumors. In addition, the data obtained were used to evaluate the significance of maximum standardized uptake value (SUVmax) in diagnosing benign or malignant lesions. For the present study, 18 patients with submandibular or sublingual neoplasms underwent F-18 FDG PET/CT imaging with accompanying CT or MRI. The diagnostic values from 43 F-18 FDG PET/CT scans and 28 CIS of the 18 patients were compared to the gold standard histopathological and/or cytopathological diagnosis. The results demonstrated that the diagnostic accuracy for predicting primary tumors was similar between F-18 FDG PET/CT and CIS. By contrast, PET/CT imaging was more accurate in detecting lymph node metastasis compared with CT or MRI (95.4 vs. 66.7%). F-18 FDG PET/CT had a sensitivity of 88.9% and a specificity of 97.1%, whereas CT or MRI had a sensitivity of 54.5% and a specificity of 75.0%. F-18 FDG PET/CT also enabled screening for distant metastasis, as observed in 10 cases in the present study. Furthermore, there were no significant differences in SUVmax between benign or malignant salivary gland lesions, as high glucose metabolism was also observed in benign tumors. In conclusion, F-18 FDG PET/CT provides more accurate diagnostic information for the evaluation of submandibular and sublingual salivary gland tumors as compared with CIS in terms of lymph node and distant metastasis.

Intraparotid mucous retention cyst in an infant: a rare case report

Mucocoeles can be defined as benign lesions that have resulted from extravasation or retention of saliva in the extraglandular spaces, and commonly affect the minor salivary glands. This case details a mucous retention cyst within the parotid gland of an infant, and its management.

Review and characteristics of 585 salivary gland neoplasms from a tertiary hospital registered in the Polish National Major Salivary Gland Benign Tumors Registry over a period of 5 years: a prospective study

&lt;b&gt;Introduction:&lt;/b&gt; A Polish National Major Salivary Gland Benign Tumors Registry (SGR) is a report of benign salivary gland neoplasms (SGNs) from 26 different centres in Poland, introduced in 2014. The aim of this study is to analyze demographic characteristics and clinico-pathological factors of benign SGNs treated in large tertiary institutions and to determine possible correlations between selected variables. &lt;br&gt;&lt;b&gt;Material and method:&lt;/b&gt; Analysis of 585 patients recorded in SGR and operated on for SGNs in the Department of Otolaryngology and Laryngological Surgery, University of Medical Sciences, Poznań, Poland, over a 5-year period. Patient age, sex, occupation, place of residence, tumor location, size, histology, recurrence, facial nerve function after surgery, wound healing, surgery procedure, availability of pre-operative imaging examinations, fine-needle aspiration cytology (FNAC) results were analyzed. &lt;br&gt;&lt;b&gt;Results:&lt;/b&gt; 338 females and 247 males with a mean age of 53 years were operated on. In total, 96.2% of tumors originated from the parotid and 3.8% from the submandibular gland. The most frequent primary tumor diameter was 2-4 cm (59.5%) followed by &lt;2 cm (29.2%) and &gt;4 cm (8.4%). Tumors of over 4 cm were frequently removed by partial superficial parotidectomy, while those under 2 cm - by extracapsullar dissection (ECD). Pleomorphic adenomas (PA) were predominant (58.8%), followed by Warthin's tumor (WT) - 37.1%. Patients with WT were on average 13.3 years older than patients with PA. &lt;br&gt;&lt;b&gt;Discussion:&lt;/b&gt; This research can be helpful to better understand the clinico-pathological features of SGNs. Long-termin hospital-based analysis is important for subsequent metaanalyses and comparisons with other centers. The reasons why not all patients' data are reported to the national SGR should be further precisely analyzed.

Accuracy of combined quantitative diffusion-weighted MRI and routine contrast-enhanced MRI in discrimination of benign and malignant salivary gland tumors

BACKGROUND

Preoperative imaging of salivary gland tumors is important for predicting and differentiating benign from malignant tumors, and for aiding management planning. We aimed to investigate the accuracy of combined quantitative diffusion-weighted magnetic resonance imaging (MRI) and routine contrast-enhanced MRI in the evaluation of salivary gland tumors and the differentiation of benign from malignant tumors.

RESULTS

This study included 51 patients with a total of 16 benign and 35 malignant lesions that were detected by histopathological analysis. There was a statistically significant difference between the apparent diffusion coefficient values (ADC) of malignant and benign lesions (0.69 ± 0.22 × 10^-3 mm²/s and 1.39 ± 0.52 × 10^-3 mm²/s respectively). The optimal cut-off ADC value was 1.08 with 75% specificity and 97% sensitivity. The routine contrast-enhanced MRI had predicted benign and malignant tumors with 65% sensitivity and 44% specificity. The sensitivity and specificity were greatly increased when quantitative diffusion-weighted MRI was combined with routine contrast-enhanced MRI: 100%, and 88% respectively. A receiver operating curve was generated. The area under curve was 0.88 (p < 0.001, 95% CI: 0.76-0.99).

CONCLUSION

Combined quantitative diffusion-weighted MRI with ADC measurements and routine contrast-enhanced magnetic resonance imaging are helpful tools for the evaluation of salivary gland tumors and help differentiate benign from malignant lesions.