Preoperative Magnetic Resonance Imaging Cannot Predict the Presence of a Rare Myoid Gonadal Stromal Testicular Tumor: A Case Report

Testicular myoid gonadal stromal tumors (MGSTs) are rare neoplasms. While past research has detailed the pathological characteristics of these tumors, the radiological differences between MGST and other types of testicular tumors have not been elucidated. Our study aimed to reveal the possible distinctive features of MGST using magnetic resonance imaging (MRI). We report a 24-year-old patient presenting with a left scrotal mass. During the patient’s preoperative MRI, we observed a testicular tumor measuring 2.5 cm that was consistent with the findings of a seminoma. The serum tumor markers were within the normal range. The T1-weighted MRI revealed a solid mass that was isointense-slightly hyperintense compared to the testicular parenchyma, while the mass appeared homogeneously hypointense on the T2-weighted imaging. The patient was planned to undergo left inguinal orchiectomy with the final pathological diagnosis of MGST. The MGST cannot be distinguished from other testicular tumors with certainty based on any MRI findings. The main tool for diagnosis should be based on the histomorphological characteristics and the immunohistochemical profile of the mass.