Successful Use of Sirolimus in Children With Large Mesenteric Lymphatic Lesions
To the Editor: We report our experience with sirolimus in children with large mesenteric lymphatic malformations refractory to conventional treatments. Cystic mesenteric lymphangiomas have a polymorphic presentation and should be surgically removed when feasible (1,2). Kaposiform hemangioendothelioma (KHE) is a locally aggressive vascular neoplasm, often associated with consumptive coagulopathy (3). Sirolimus, an mTOR inhibitor, plays a key role in angiogenesis signaling pathway and consequently on tumoral growth (4). There are few reports on sirolimus efficacy in large lymphatic lesions, but no long-term follow-up (4–6). Three children with severe mesenteric lymphatic lesions (2 cystic lymphangiomas and 1 KHE) were treated with sirolimus (Table 1). Two patients had refractory chylous ascites, severe diarrhea, and fever; the 1 with KHE had prenatal ascites, and at birth hemorrhagic ascites and thrombocytopenia. Surgery, embolization, laser, and sclerotherapy were considered not feasible. After failure of fat-free diet, parenteral nutrition, steroids, calcium heparin, octreotide and tranexamic acid, sirolimus was introduced, with a target trough blood level at 7 to 12 ng/mL. All of the patients achieved complete clinical remission, although partial on imaging, with a mean follow-up of 8 years. At last follow-up, all patients were still on treatment with trough blood level around 5 ng/mL. Sirolimus was well tolerated. Our patients had voluminous and complex malformations, and we decided to try a less invasive and innovative medical therapy. Long-term treatment with sirolimus is effective and safe in children with inextirpable mesenteric lymphatic lesions. It should be considered early in these patients’ care.