Comparative Analysis of Imaging and Pathological Features in Diagnosis of Ovarian Adult Granulosa Cell Tumor with Sarcomatoid Transformation Based on CT and Multimodal MRI

Author(s): Jin Ying Lan, Jin Han Yang, Dong Wu Chen, Yuan Hui Liang

Ovarian adult granulosa cell tumor (AGCT) is a rare, low-grade malignant sex cord–stromal tumor of the ovary that can occasionally exhibit sarcomatoid transformation—a rare and highly aggressive histologic subtype. The biological behavior and imaging manifestations of AGCT with sarcomatoid transformation differ markedly from those of conventional ovarian AGCT. Here, we report the imaging findings of a rare case of ovarian AGCT with sarcomatoid transformation. Integrated imaging with computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated the coexistence of conventional tumor components and areas of sarcomatoid transformation within the same lesion. The sarcomatoid component exhibited more aggressive imaging features, including markedly enhancing large solid masses, extensive necrosis, T2-weighted imaging (T2WI) hypointensity, and pronounced diffusion restriction on diffusion-weighted imaging (DWI), all of which correlated closely with postoperative histopathology. Histologically, regions of conventional granulosa cell tumor contained Call-Exner bodies and relatively bland cytology, whereas the sarcomatoid areas comprised highly atypical spindle cells with increased mitotic activity, consistent with high-grade sarcoma. This case underscores the value of multimodal MRI in preoperatively identifying intratumoral heterogeneity and suggesting sarcomatoid transformation, thereby providing crucial information to guide more aggressive surgical and adjuvant treatment strategies. Although surgical resection remains the primary treatment modality, comprehensive preoperative imaging evaluation is essential. Nevertheless, there is currently limited literature on the role of preoperative multimodal MRI in diagnosing and differentiating ovarian AGCTs with sarcomatoid transformation.