Affiliations: [a] Department of Radiology, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| [b] Department of Radiology, Zhuhai Hospital of Jinan University, Zhuhai People’s Hospital, Zhuhai, China
| [c] Department of Pathology, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
Correspondence:
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Corresponding author: Wei-Jun Peng, MD, PhD, Department of Radiology, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, 270 Dongan Road, Xuhui District, Shanghai 200032, China. Tel.: +86-15026544096; Fax: +86-21-64175590; E-mail: weijun6002@163.com.
Note: [1] Wei-Tang and Xiang-Rong Yu contributed equally to this work and should be considered co-first authors.
Abstract: OBJECTIVES:This study aimed to describe the computed tomography (CT), magnetic resonance imaging (MRI) imaging features of adrenal schwannoma and to correlate imaging findings with histopathologic findings. METHODS:The findings from multiphase CT or MRI examinations of seventeen patients with histopathologically confirmed adrenal schwannoma were reviewed. The imaging criteria included shape, size, margin, attenuation, signal intensity, secondary degeneration, and internal mass enhancement pattern. RESULTS:All cases were unilateral, round or oval solitary tumors, with diameters ranging from approximately 2.5 to 8.8 cm (median = 4.5 cm). Of the twelve cases assessed using CT, adrenal schwannoma appeared as well-circumscribed round or oval low-density suprarenal masses with a mean attenuation values of 30.1 HU of solid portions during unenhanced phase. Ten cases exhibited heterogeneous cyst formation, and one case showed calcification. Internal septa were noted in 5 cases. All solid areas displayed early mild heterogeneous enhancement and delayed progressive enhancement. Regarding MRI, solid portions of five masses were hypointense to the liver parenchyma on T1-weighted imaging (T1WI) and were heterogeneously hyperintense on T2-weighted imaging (T2WI). The enhanced pattern of solid areas of adrenal schwannoma on MRI is similar to that of CT. Cystic or hemorrhagic changes were noted in 4 cases and internal septa were noted in 3 cases. CONCLUSION:Although schwannoma is a rare entity in the adrenal gland, we believe that the following signs may suggest the diagnosis of this entity: a non-lipid containing mass, a well-defined border, a unilateral mass with cystic or hemorrhagic degeneration, septa with delayed enhancement and a characteristic progressive contrast enhancement pattern of the solid portions.
