A Rare Case of Retroperitoneal Teratoma Mimicking Paraganglioma on Multimodality Imaging.

Liu, Yang; Guo, Rui; Cui, Yan; Liu, Yitong; Li, Nan · Clin Nucl Med · 2026

case_report · Level V

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Abstract

A 28-year-old woman incidentally palpated an asymptomatic abdominal mass. Contrast-enhanced MRI revealed a retroperitoneal mass with arterial phase hyperenhancement and mild delayed-phase washout, raising suspicion for paraganglioma. 18 F-FDG PET/CT showed a soft tissue mass with mild and heterogeneous 18 F-FDG uptake, while 68 Ga-DOTATATE PET/CT revealed intense uptake, further supporting the presumptive diagnosis of paraganglioma. However, postoperative pathology confirmed a teratoma containing thyroid tissue with positive somatostatin receptor (SSTR) 2 and SSTR 5 expression, which may explain the false-positive uptake on 68 Ga-DOTATATE. This case may provide a critical differential diagnostic consideration in retroperitoneal masses with high 68 Ga-DOTATATE uptake.

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