Intra-abdominal lymphatic malformation management in light of the updated International Society for the Study of Vascular Anomalies classification

Abstract
The International Society for the Study of Vascular Anomalies (ISSVA) classification distinguishes between common lymphatic malformations and complex lymphatic anomalies. These entities have overlapping features but differing responses to treatment. Surgery has been the mainstream treatment in intra-abdominal lymphatic malformation, with variable reported success in the literature. The aim of this study was to review the outcome of different treatments for intra-abdominal lymphatic malformations in children. We retrospectively reviewed all intra-abdominal lymphatic malformations from 1999 to 2019 in children treated by the surgical team or followed in the vascular anomalies clinic of our institution. Children were classified into one of three groups: group A, isolated intra-abdominal lymphatic malformation; group B, common lymphatic malformation in continuity with other regions; or group C, intra-abdominal involvement as part of a complex lymphatic anomaly or associated syndrome. Fifty intra-abdominal lymphatic malformations were diagnosed; five of these were excluded. In group A (n=28), the treatment was surgical resection (n=26) or sclerosing treatment (n=1), with one case of spontaneous regression; no recurrence was observed in 25 patients. In group B (n=7), three patients had partial resection and all had recurrence; four had sclerotherapy alone with good response. In group C (n=10), therapeutic options included surgery, sclerosing treatment and pharmacotherapy, with variable outcomes. The management of intra-abdominal malformations requires a team approach. Sclerotherapy is successful in treating macrocystic lymphatic malformation. Surgery is successful in treating isolated intra-abdominal common lymphatic malformation, albeit at times at the cost of intestinal resection, which could be avoided by combining surgery with preoperative sclerotherapy. With surgery there is often limited resectability, and therefore recurrence in intra-abdominal lymphatic malformations that are part of complex lymphatic anomalies associated with syndromes, or in common lymphatic malformations in continuity with other regions. Sclerotherapy is an effective modality in these instances along with pharmacotherapy.