A case series of radiologically misdiagnosed visceral lymphatic malformations.

Background: Visceral lymphatic malformation (LM) was rare and was easily misdiagnosed on imaging. This study aims to explore the clinicopathological and imaging findings of a series of visceral LM. Cases Description: The clinicopathological and imaging [computed tomography (CT) and/or magnetic resonance imaging (MRI)] findings of 11 radiologically misdiagnosed visceral LM were reviewed. The median age was 34 years old, with a sex ratio (male:female) of 1.2:1. Most were asymptomatic and found incidentally. Their locations were the lung, liver, spleen, and pancreas. They were all cystic masses, with or without septa, and mainly showed fluid attenuation on unenhanced CT (one filled with gas), hypo-signal intensity (SI) on T1WI, and hyper-SI on T2WI with/without internal hypo-SI fibrous septa. The septa showed mild to moderate enhancement. These masses were misdiagnosed as congenital pulmonary airway malformation (CPAM), hepatic mesenchymal hamartoma, splenic cyst, pancreatic intraductal papillary mucinous neoplasms (IPMN), mucinous cystadenoma, serous cystadenoma, and pancreatic ductal adenocarcinoma. They were all excised surgically. The positive rates of D2-40, CD31, and F8 staining were 100%, 100%, and 83.3%, respectively. Conclusions: Visceral LM were all cystic masses (multicysts or unilocular); mainly showed hypo-attenuation on unenhanced CT, hypo-SI on T1WI, and hyper-SI on T2WI with internal thin and uniform hypo-SI septa showing mild to moderate enhancement. It commonly expressed D2-40, CD31, and F8. LM should be reminded of the differentiation of visceral cystic mass.