WOFAPS 2025 8th World Congress of Pediatric Surgery

Jiajun Xu, Yue Gao, Yunxiang Qiu, Jiajie Fan, Qiang Shu, Zheng Tan, Shanshan Shi

Children's Hospital Zhejiang University of Medicine

Kaposiform lymphangiomatosis (KLA) is a rare and aggressive lymphatic anomaly characterized by multifocal proliferation of malformed lymphatic vessels and life-threatening hemorrhagic complications. We report a case of a 3-year-old boy presenting with recurrent chylothorax, hemorrhagic pericardial and pleural effusions, coagulopathy, and thrombocytopenia. Imaging and pathology confirmed the diagnosis of KLA. Genetic testing revealed an NRAS p.Q61R somatic mutation. Despite initial therapy with sirolimus and vincristine, the disease progressed. Following the addition of the MEK inhibitor trametinib, and surgical interventions including mediastinal mass resection and pleural decortication, the patient's condition improved significantly. Histopathological examination and immunohistochemistry supported the diagnosis. This case highlights the clinical utility of trametinib as a targeted therapy in NRAS-mutated KLA and underscores the importance of a multimodal, individualized treatment strategy in managing complex pediatric vascular anomalies.