Lesser omental capillary-lymphatic-venous malformation with massive intralesional hemorrhage: A case report.

Lesser omental cystic capillary-lymphatic-venous malformation (CLVM) is a rare benign intra-abdominal vascular anomaly. We report the case of a 50-year-old female patient who was admitted to our hospital with epigastric pain. She was previously diagnosed with abdominal cystic lymphangioma. At the time of her visit to our hospital, abdominal computed tomography (CT) revealed massive intralesional hemorrhage. During tumor resection, the cystic lesion was found to originate from the lesser omentum. Histopathologically, the patient was diagnosed with CLVM instead of lymphangioma, based on the 2018 International Society for the Study of Vascular Anomalies (ISSVA) classification. Hemorrhage within the cyst may alter lesion imaging features, thereby complicating preoperative diagnosis. Preoperatively, we were unable to identify imaging features of vascular components other than the lymphatic component. In our case, the hemorrhage may have been caused by vascular structures pathologically identified within the lesion. Therefore, we speculated that previously reported cases of abdominal lymphangiomas complicated by hemorrhage may harbor combined vascular malformations had they been pathologically reclassified according to the 2018 ISSVA classification system. We report a case of lesser omentum CLVM that subsequently developed into intralesional hemorrhage, with a review of the relevant literature.