Challenges with preoperative diagnosis of low/intermediate-grade carcinoma of the parotid gland: single-center study of 112 patients

Topology-based radiomic features for prediction of parotid gland cancer malignancy grade in magnetic resonance images

PURPOSE

The malignancy grades of parotid gland cancer (PGC) have been assessed for a decision of treatment policies. Therefore, we have investigated the feasibility of topology-based radiomic features for the prediction of parotid gland cancer (PGC) malignancy grade in magnetic resonance (MR) images.

MATERIALS AND METHODS

Two-dimensional T1- and T2-weighted MR images of 39 patients with PGC were selected for this study. Imaging properties of PGC can be quantified using the topology, which could be useful for assessing the number of the k-dimensional holes or heterogeneity in PGC regions using invariants of the Betti numbers. Radiomic signatures were constructed from 41,472 features obtained after a harmonization using an elastic net model. PGC patients were stratified using a logistic classification into low/intermediate- and high-grade malignancy groups. The training data were increased by four times to avoid the overfitting problem using a synthetic minority oversampling technique. The proposed approach was assessed using a 4-fold cross-validation test.

RESULTS

The highest accuracy of the proposed approach was 0.975 for the validation cases, whereas that of the conventional approach was 0.694.

CONCLUSION

This study indicated that topology-based radiomic features could be feasible for the noninvasive prediction of the malignancy grade of PGCs.

The Diagnostic Value of Fine Needle Aspiration Biopsy in Parotid Tumors

The aim of this study was to investigate the diagnostic accuracy rates of the patients who underwent an operation for parotid mass, by comparing their fine needle aspiration biopsy (FNAB) cytology results with the final pathology. A total of 136 patient files of those who applied to Otorhinolaryngology clinic due to parotid mass and underwent parotidectomy procedure between 2010 and 2020 at a tertiary center were scanned retrospectively. Database on patient age, gender, preoperative FNAB results, and final surgical histopathology results was created. The mean age of the patients was 48.26 ± 17.37 Superficial parotidectomy was performed to 108 (79.4%) and total parotidectomy to 28 (20.6%) of the patients. The sensitivity of FNAB was found as 85.2%, specificity as 96.2%, positive predictive value as 85.2%, negative predictive value as 96.2% and accuracy as 94.0%. It is found that FNAB has the high specificity and high negative predictive value with high diagnostic accuracy on detecting preoperative malignancy in parotid gland. We think that FNAB is a significant, necessary and safe method in the diagnosis of parotid lesions in preoperative sense.

Short communication: Distribution of phospholipids in parotid cancer by matrix-assisted laser desorption/ionization imaging mass spectrometry

Background

Parotid cancer is relatively rare, and malignancy varies; therefore, novel markers are needed to predict prognosis. Recent advances in matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS), useful for visualization of lipid molecules, have revealed the relationship between cancer and lipid metabolism, indicating the potential of lipids as biomarkers. However, the distribution and importance of phospholipids in parotid cancer remain unclear.

Objective

This study aimed to use MALDI-IMS to comprehensively investigate the spatial distribution of phospholipids characteristically expressed in human parotid cancer tissues.

Methods

Tissue samples were surgically collected from two patients with parotid cancer (acinic cell carcinoma and mucoepidermoid carcinoma). Frozen sections of the samples were assessed using MALDI-IMS in both positive and negative ion modes, with an m/z range of 600–1000. The mass spectra obtained in the tumor and non-tumor regions were compared and analyzed. Ion images corresponding to the peak characteristics of the tumor regions were visualized.

Results

Several candidate phospholipids with significantly different expression levels were detected between the tumor and non-tumor regions. The number of unique lipid peaks with significantly different intensities between the tumor and non-tumor regions was 95 and 85 for Cases 1 and 2, respectively, in positive ion mode, and 99 and 97 for Cases 1 and 2, respectively, in negative ion mode. Imaging differentiated the characteristics that phospholipids were heterogeneously distributed in the tumor regions.

Conclusion

Phospholipid candidates that are characteristically expressed in human parotid cancer tissues were found, demonstrating the localization of their expression. These findings are notable for further investigation of alterations in lipid metabolism of parotid cancer and may have potential for the development of phospholipids as biomarkers.

Diagnostic Accuracy and Post-Procedural Complications Associated with Ultrasound-Guided Core Needle Biopsy in the Preoperative Evaluation of Parotid Tumors

Correct diagnosis of a parotid neoplasm based on histology preoperatively is of utmost importance in order to guide patient management. The aim of this study was to evaluate the diagnostic accuracy of an ultrasound-guided core needle biopsy of a parotid lesion and to describe associated post-procedural complications. A retrospective study was conducted between January 2015 and March 2021 of all patients who were referred to a tertiary care center for evaluation of a parotid lesion and who underwent core needle biopsy due to high-risk features or when malignancy was suspected on clinical examination or ultrasonography. Patient characteristics, histological findings, and post-procedural complications were recorded and evaluated. Among 890 patients referred for evaluation of a parotid lesion, in 138 patients a core needle biopsy was undertaken. On the basis of core needle biopsy findings, 11 lymphomas and 82 non-lymphoma malignancies were diagnosed in the parotid gland. The sensitivity of the core needle biopsy predicting the accurate tumor type was 97.56% (95% CI 91.47-99.70%) and the specificity 94.64% (95% CI 85.13-98.88%). The accuracy for the correct histopathological diagnosis was 93.48% (95% CI 87.98-96.97%). Post-procedural minor complications occurred in 19 patients (13.8%). In conclusion, a core needle biopsy can identify malignancy in the parotid gland with high sensitivity and specificity in a safe manner and therefore guide surgical treatment.

Pretherapeutic Predictive Factors for Histological High-Grade Parotid Gland Carcinoma

OBJECTIVE

The histological grade of parotid gland carcinoma (PGC) is an important prognostic factor; however, the diagnosis prior to treatment has been challenging to make. This study aimed to investigate whether the pretreatment clinical findings, including hematological inflammatory, nutritional, and immune markers, could predict the histological grade of PGC.

STUDY DESIGN

Retrospective study.

METHODS

We retrospectively enrolled 111 patients with PGC and evaluated the correlation between histological grade and pretreatment clinical findings such as age, sex, tumor staging, facial nerve paralysis, pain or tenderness, adhesion to the surrounding tissues or tumor immobility, and hematological markers.

RESULTS

Sixty patients (54%) were diagnosed with histological high-grade PGC. Univariate analysis revealed that age, T classification, N classification, TNM stage, facial nerve paralysis, adhesion/immobility, C-reactive protein (CRP), and CRP-to-albumin ratio (CAR) were significant predictors of PGC histological grade. On multivariate analysis, high T classification (T3, 4), high N classification (≥1), and elevated CRP (≥0.22 mg/dL) were independent predictors of high-grade PGC.

CONCLUSIONS

Pretreatment T classification, N classification, and CRP are significant predictors of the histological grading of PGC. Our results are useful for treatment planning and obtaining appropriate informed consent from the patients before treatment.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Effective surgical management of anterior tumors of the parotid gland: Main trunk method vs. peripheral Smethod

OBJECTIVE

Several surgical procedures have been proposed for tumors in the anterior parotid gland. Although the standard approach to other parotid tumors is generally also used for anterior tumors, handling of the facial nerve has not been addressed in any previous reports.

METHODS

A total of 654 patients with benign parotid tumors who underwent surgery in our department were classified into anterior (AT), middle (MT), and posterior tumor (PT) groups according to tumor location. Clinical characteristics, histopathological types, and frequency of postoperative transient facial palsy were examined. In the AT group, two surgical methods were compared, which were the main trunk method (MTM) and the peripheral method (PM).

RESULTS

172 patients were included in the AT group, 175 in the MT group, and 307 in the PT group. The AT group showed significant female predominance and a higher percentage of deep lobe tumors than the PT group. There was no significant difference in the rate of postoperative transient facial palsy among the AT (MTM), MT, and PT groups. The PM had a significantly shorter operating time and lower rate of transient facial palsy than the MTM.

CONCLUSION

The PM for AT was considered a useful surgical method from the standpoints of postoperative complications and operating time. In the PM, a wide operating field made identification of the facial nerve easier.

Basal cell adenocarcinoma of the parotid gland: Comparison with basal cell adenoma for preoperative diagnosis

OBJECTIVE

To summarize the diagnosis and treatment outcomes of basal cell adenocarcinoma (BCAC) of the parotid gland, a rare low-grade malignancy, at a single institution, and to investigate the treatment approach for this rare malignancy.

METHODS

We conducted a retrospective analysis of 9 patients with BCAC during 20 years from September 1999 to December 2019. Forty-five patients with basal cell adenoma (BCA), who were treated during the same time period, were used for comparison. The clinical characteristics of BCAC, diagnostic imaging, the usefulness of fine-needle aspiration cytology (FNAC) and frozen section biopsy (FSB), histological assessment of malignancy, and treatment outcomes were investigated.

RESULTS

There were no marked differences in sex, age, tumor diameter, or tumor location between BCAC and BCA cases. Among the 9 patients with BCAC, one patient was noted with pain/tenderness, and two patients were observed with adhesion to the surrounding tissues. Only one patient was diagnosed as malignant based on MRI/US. FNAC for BCAC was suspicious for malignancy in 6 of the 9 cases, which included one patient with the correct grade of malignancy, one patient with malignancy only, and 4 patients suspicious for malignancy. FSB was suspicious for malignancy in 8 of the 9 cases. Malignancy grade was determined based on infiltration to the surrounding tissues and expression of Ki-67, p53, and bcl-2. One patient with infiltration to the surrounding tissue was diagnosed as intermediate-grade malignancy, while the remaining 8 patients were diagnosed as low-grade malignancy. The BCAC cases included 7 patients with T2 and 2 patients with T1. Conservative resection was performed for all patients, and all cases are surviving cancer-free.

CONCLUSION

The malignancy of BCAC can be suspected before surgery based on symptoms/signs, diagnostic imaging, and FNAC. FSB enables the diagnosis of not only malignancy but also the grade of malignancy, which may help determine the appropriate surgical resection. Although all 9 patients with BCAC are surviving free from cancer, a long-term follow-up is warranted.