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Parotid pleomorphic adenoma: can a biopsy be omitted in the setting of a characteristic MRI?
Amy S Wong1,2,3, Pramit M Phal4,5, Michelle Thong6,7
1Department of Otolaryngology Head and Neck Surgery, Epworth HealthCare, Melbourne, VIC, Australia. amyw2@student.unimelb.edu.au.
Objective:
Pleomorphic adenoma (PA) is the most common benign parotid tumour. Magnetic resonance imaging (MRI) and fine-needle aspiration cytology (FNAC) are routinely used during preoperative work up. However, there is insufficient evidence to support the use of MRI alone to diagnose a PA. This paper aims to evaluate the diagnostic performance of MRI and FNAC in the diagnosis of PA and develop an MRI assessment tool to potentially reduce an invasive biopsy.
Methods:
A retrospective cohort study was conducted in 155 patients with histopathologically confirmed parotid tumours with preoperative MRI and/or FNAC between 2015 and 2020. Two experienced head and neck radiologists, both with over 20 years' experience, blinded to final histopathology, evaluated 100 MRIs. Diagnostic values for detecting PA with MRI and FNAC were evaluated. An MRI assessment tool was developed based on clinical criteria and MRI characteristics typical for a PA.
Results:
The sensitivity, specificity, positive predictive value (PPV), negative predictive value, (NPV) and diagnostic accuracy for predicting PA were 93%, 97%, 96%, 94% and 95% (Area under ROC curve (AUC) 0.95) for FNAC and 95%, 90%, 86%, 96% and 92% (AUC 0.93) for MRI respectively. There was no statistically significant difference between MRI and FNAC for diagnosing PA with regards to sensitivity (p = 0.628), specificity (p = 0.162) or overall accuracy (p = 0.361).
Conclusion:
MRI is a noninvasive imaging technique that can predict PA with similar sensitivity, specificity and diagnostic accuracy compared with FNAC. The PA MRI assessment tool aims to assist in surgical management decisions, while potentially reducing the need for an invasive biopsy.
Insights
Magnetic resonance imaging (MRI) and fine-needle aspiration cytology (FNAC) accurately diagnose pleomorphic adenoma (PA). MRI offers a non-invasive alternative to FNAC, potentially reducing the need for biopsies.
Area of Science:
- Radiology
- Oncology
- Diagnostic Imaging
Background:
- Pleomorphic adenoma (PA) is the most common benign parotid tumor.
- Preoperative diagnosis typically involves MRI and FNAC.
- Current evidence is insufficient to support MRI alone for PA diagnosis.
Purpose of the Study:
- Evaluate the diagnostic performance of MRI and FNAC for PA.
- Develop an MRI assessment tool to potentially reduce invasive biopsies.
Main Methods:
- Retrospective cohort study of 155 patients with parotid tumors (2015-2020).
- Preoperative MRI and/or FNAC data analyzed.
- Two experienced radiologists evaluated 100 MRIs blinded to histopathology.
Main Results:
- FNAC: 93% sensitivity, 97% specificity, 95% accuracy (AUC 0.95).
- MRI: 95% sensitivity, 90% specificity, 92% accuracy (AUC 0.93).
- No statistically significant difference in diagnostic performance between MRI and FNAC.
Conclusions:
- MRI can predict PA with comparable sensitivity, specificity, and accuracy to FNAC.
- An MRI assessment tool can aid surgical decisions and potentially reduce invasive biopsies.
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Computed Tomography (CT) scan:
Computed Tomography (CT) scans use X-ray technology to generate detailed images of bones, organs, and tissues. During the scan, the patient lies on a moving table...