MR imaging features of benign retroperitoneal paragangliomas and schwannomas

Yanguang Shen,Zhonghua Sun,Yingwei Wang,Huiyi Ye,Kun Zhang,Yan Zhong,Haiyi Wang,Lu Ma

doi:10.1186/s12883-017-0998-8

Yanguang Shen, Zhonghua Sun + Show 6 more

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https://doi.org/10.1186/s12883-017-0998-8

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Abstract

BackgroundTo determine whether MRI feature analysis can differentiate benign retroperitoneal extra-adrenal paragangliomas and schwannomas.MethodsThe MRI features of 50 patients with confirmed benign retroperitoneal extra-adrenal paragangliomas and schwannomas were retrospectively reviewed by two radiologists blinded to the histopathologic diagnosis. These features were compared between two types of tumours by use of the Mann-Whitney test and binary logistic regression. The patients’ clinical characteristics were reviewed.ResultsAnalysis of MRI images from 50 patients revealed no significant differences in the quantitative MRI features of lesion size, ratio of diameter and apparent diffusion coefficient. There were significant differences in the qualitative MRI features of location, necrosis, cysts and degree of tumour enhancement for two readers, with no significant differences in the other qualitative MRI features between these tumours. The combination of necrosis with degree of tumour enhancement during the arterial phase increased the probability that a retroperitoneal mass would represent retroperitoneal extra-adrenal paraganglioma as opposed to schwannoma.ConclusionWe have presented the largest series of MRI features of both benign retroperitoneal extra-adrenal paragangliomas and schwannomas. Some MRI features assist in the differentiation between these tumours, with imaging features consisting of necrosis and avid enhancement during the arterial phase, suggestive of retroperitoneal extra-adrenal paragangliomas.

Highlights

To determine whether Magnetic resonance imaging (MRI) feature analysis can differentiate benign retroperitoneal extra-adrenal paragangliomas and schwannomas
To the best of our knowledge, description of the MRI features of retroperitoneal extra-adrenal paragangliomas and schwannomas has been reported on small sample sizes in the literature, and no joint assessment has been performed for the imaging appearances of these two similar entities, which may be expected to have overlapping imaging findings in view of their common pathologic characteristics
Demographic data and clinical characteristics In this study, a total of 50 lesions in 50 patients were identified for inclusion in the analysis, consisting of 24 retroperitoneal extra-adrenal paragangliomas (Fig. 1) and 26 retroperitoneal schwannomas (Fig. 2)

Summary

Introduction

To determine whether MRI feature analysis can differentiate benign retroperitoneal extra-adrenal paragangliomas and schwannomas. Primary neurogenic tumours, which constitute 10% to 20% of primary retroperitoneal tumours, occur in a younger age group and are usually benign [1]. These tumours can be classified as ganglion cell origin, paraganglionic system origin (pheochromocytomas and paragangliomas), or nerve sheath origin (neurilemmomas, neurofibromas, neurofibromatosis, and malignant nerve sheath tumours). To the best of our knowledge, description of the MRI features of retroperitoneal extra-adrenal paragangliomas and schwannomas has been reported on small sample sizes in the literature, and no joint assessment has been performed for the imaging appearances of these two similar entities, which may be expected to have overlapping imaging findings in view of their common pathologic characteristics. The purpose of our study was to retrospectively analyse the MRI imaging differences of benign retroperitoneal extra-adrenal paragangliomas and schwannomas, for those with non-functional paragangliomas

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