Abdominal cystic lymphangiomas are uncommon congenital benign tumors. Ninety-five percent of lymphangiomas occur in the head and axilla, while intra-abdominal lesions (e.g., located in the omentum, mesentery and retroperitoneum) are rare.
Lymphangiomas result from the abnormal development of the lymphatic system. Pathologically, the lymphatic tissue of the small bowel or retroperitoneum does not communicate with the main lymphatic vessels, which leads to the development of a cystic mass formation.
Abdominal lymphangiomas are more common in boys and usually occur in childhood. The study performed by Konen (et al) showed a male-to-female ratio of 5:2 and mean age at presentation of 2.2 years.
The clinical symptoms are variable. An abdominal lymphangioma may be diagnosed incidentally on prenatal US, as it was initially identified in this patient, but chronic or acute symptoms are common. Chronic symptoms include chronic abdominal pain and progressive abdominal distension. Acute symptoms usually include acute abdominal pain and distension, vomiting, fever and peritonitis.
Due to the variable presentation, complex imaging studies are necessary when evaluating this condition. Both US and CT have been shown to be very sensitive in the diagnosis.
Plain abdominal radiographs most commonly reveal a soft-tissue mass with displacement of bowel loops. Although not diagnostic, plain films help to identify complications such as bowel displacement and/or intestinal obstruction. On US, a cystic lymphangioma appears as a sharply defined cystic or multicystic mass often with internal septations. On CT, the typical appearance is a large, thin-walled, multiseptated cystic mass with usually homogeneous fluid contents. CT also plays an important role in providing key preoperative information such as anatomical location, adjacent organ involvement, size and complications.
Complete resection is the treatment of choice and has an excellent prognosis. Although an abdominal lymphangioma is considered benign, it may become locally invasive. Therefore any involved organ must also be resected. Incomplete resection may lead to recurrence. Follow-up imaging, therefore, is advised, with ultrasound as the modality of choice.