The primary purpose of this study is to retrospectively identify the clinical characteristics of abdominal lymphatic malformations (ALMs) in our single center in China. The second objective of this study is to retrospectively compare the epidemiological features, clinical presentations, cyst properties, surgical treatments, and risk factors for preoperative complications of ALMs between paediatric participants and adult participants.

Lymphatic malformations (LMs) are vascular anomalies that arise from abnormal embryonic development of the lymphatic system and can present as dilated lymphatic channels or cysts lined by lymphatic endothelial cells. Abdominal lymphatic malformations (ALMs) are rare entities that account for fewer than 10% of LMs and may occur not only in the tissues or organs in the abdominal cavity, such as the mesentery, spleen and pancreas but also in the retroperitoneal space. ALMs can manifest as an infection, chronic abdominal discomfort, acute abdomen, or fatal disease.

Inclusion Criteria:

• The investigators enrolled participants who were pathologically diagnosed with lymphangioma or lymphatic malformations in the abdominal cavity (i.e., abdominal lymphatic malformations) from January 2009 to December 2022 at our institution.

Exclusion Criteria:

• The investigators excluded participants without a pathological diagnosis of abdominal lymphatic malformations through resection specimens and those with pathological confirmation of other diseases, as well as patients with complex lymphatic anomalies.

In this study, The investigators retrospectively collected and compared the data related to the preoperative information, intraoperative findings and postoperative pathological analysis of the enrolled abdominal lymphatic malformations for paediatric and adult participants.