Desmoplastic Small Round Cell Tumor: a study of CT, MRI, PET/CT multimodal imaging features and their correlations with pathology.

Purpose: Exploring the computed tomography (CT), magnetic resonance imaging (MRI), and fluorodeoxyglucose positron emission tomography (FDG-PET)/CT Multimodal Imaging Characteristics of Desmoplastic Small Round Cell Tumor (DSRCT) to enhance the diagnostic proficiency of this condition.

Methods: A retrospective analysis was performed on clinical data and multimodal imaging manifestations (CT, MRI, FDG-PET/CT) of eight cases of DSRCT. These findings were systematically compared with pathological results to succinctly summarize imaging features and elucidate their associations with both clinical and pathological characteristics.

Results: All eight cases within this cohort exhibited abdominal-pelvic masses, comprising six solitary masses and two instances of multiple nodules, except for one case located in the left kidney, the remaining cases lacked a clear organ source. On plain images, seven cases exhibited patchy areas of low density within the masses, four cases showed calcification within the masses. Post-contrast imaging displayed mild-to-moderate, uneven enhancement. Larger masses displayed patchy areas without significant enhancement at the center. In the four MRI examinations, T1-weighted images exhibited uneven, low signal intensity, while T2-weighted images demonstrated uneven high signal intensity. Imaging unveiled four cases of liver metastasis, four cases of ascites, seven cases of lymph node metastasis, three cases of diffuse peritoneal thickening, and one case involving left ureter invasion with obstruction. In the FDG-PET/CT examinations of seven cases, multiple abnormal FDG accumulations were observed in the abdominal cavity, retroperitoneum, pelvis, and liver. One postoperative case revealed a new metastatic focus near the colonic hepatic region. The range of maximum standardized uptake values (SUV) for all lesions are 6.62-11.15.

Conclusions: DSRCT is commonly seen in young men, and the imaging results are mostly multiple lesions with no clear organ source. Other common findings include intratumoral calcification, liver metastasis, ascites, peritoneal metastasis, and retroperitoneal lymph node enlargement. The combined use of CT, MRI and FDG-PET/CT can improve the diagnostic accuracy and treatment evaluation of DSRCT. However, it is imperative to underscore that the definitive diagnosis remains contingent upon pathological examination.