CT and MRI features of undifferentiated embryonal sarcoma of liver in adults

Objective To analyze the CT and MRI manifestations of undifferentiated hepatic embryonal sarcoma in adults with an aim to improve the preoperative diagnosis of this disease. Methods A retrospective analysis was carried out on the clinical data of 11 patients with undifferentiated hepatic embryonal sarcoma treated in Wenzhou People’s Hospital of Zhejiang and Wenzhou Central Hospital of Zhejiang between January 2008 and December 2018. There were 5 males and 6 females. The age ranged from 46 to 76 years (median 64 years). The site, size, morphology, margin, and pattern and degree of enhancement of the tumors were analyzed. Results Among the 11 patients, 10 patients had a single tumor, only 1 patient had multiple tumors. A total of seven patients' tumors were located in the right liver, 2 in the left liver, and 2 involved both the left and right livers. The maximum diameter of the tumors ranged from 5.5 cm to 21.2 cm, the maximum diameter (10.2±4.8 cm). The edge of tumors was clear in 9 patients and unclear in 2 patients. The tumors were elliptical in 4 patients or irregular in 7 patients. Plain CT scan showed 4 patients' tumors had mainly a cystic component, while 5 patients had both cystic and solid components. Plain MRI scan showed that five tumors were cystic and solid, with mixed internal signals. T1 weighted imaging (T1WI) showed slightly lower and lower signals; T2 weighted imaging (T2WI) showed slightly higher and higher signals. There was a low signal stripe separating inside; Diffusion-weighted imaging showed a high signal and apparent diffusion coefficient showed a low signal. The enhancement was characterized by "fast in and fast out" (marked enhancement in the arterial phase and fast clearance in the venous phase), and "delayed enhancement" (mild to moderate enhancement in the arterial phase and even more obvious enhancement in the venous or delayed phase). Conclusion Adult undifferentiated embryonic sarcoma has certain CT and MRI features. Its shape is elliptical or irregular, and mostly with a clear boundary. There were intratumoral cystic or cystic solid components, with mixed density/signal on CT and MRI, being characterized by "fast in and fast out" and "delayed enhancement" on intravenous contrast enhanced scans. Key words: Liver neoplasms; Tomography, X-ray computed; Magnetic resonance imaging; Undifferentiated embryonal sarcoma