Is PET/CT Able to Predict Histology in Thymic Epithelial Tumours? A Narrative Review

Abstract

Background: The usefulness of 18FDG PET/CT scan in the evaluation of thymic epithelial tumours (TETs) has been reported by several authors, but data are still limited and its application in clinical practice is far from being defined. Methods: We performed a narrative review of pertinent literature in order to clarify the role of 18FDG PET/CT in the prediction of TET histology and to discuss clinical implications and future perspectives. Results: There is only little evidence that 18FDG PET/CT scan may distinguish thymic hyperplasia from thymic epithelial tumours. On the other hand, it seems to discriminate well thymomas from carcinomas and, even more, to predict the grade of malignancy (WHO classes). To this end, SUVmax and other PET variables (i.e., the ratio between SUVmax and tumour dimensions) have been adopted, with good results. Finally, however promising, the future of PET/CT and theranostics in TETs is far from being defined; more robust analysis of imaging texture on thymic neoplasms, as well as new exploratory studies with “stromal PET tracers,” are ongoing. Conclusions: PET may play a role in predicting histology in TETs and help physicians in the management of these insidious malignancies.

Thymic Epithelial Tumors: An Evolving Field

“…Positron emission tomography (PET) is crucial in distinguishing between thymoma and thymic carcinoma, although there is little evidence about its role in differentiating hyperplasia from thymoma. Furthermore, the PET scan is a good predictor of TET histological classification [ 103 ].…”

Development and Validation of A Diagnostic Nomogram Based on PET/CT and Clinical Characteristics: Differentiating mediastinal lymphomas from aggressive thymic epithelial tumors

“…However, relying solely on morphological assessment cannot effectively differentiate between aTETs and PMLs, leading to unnecessary thymectomies or thoracotomies [12,13]. In recent years, the use of 18F-uoro-2deoxy-D-glucose positron emission tomography/computed tomography(18F-FDG PET/CT)in the evaluation of anterior mediastinal masses has gained popularity, as it not only delineates the anatomical structure of the lesion but also provides metabolic information [14]. While there have been studies exploring the role of PET/CT metabolic parameters in distinguishing TETs from PMLs, previous research didn't consider the differences in aggressiveness of TETs, often grouping low-risk thymomas and aTETs together for differentiation from mediastinal lymphomas [15][16][17].…”