Although lymphangiectasia is common in the neck and axilla, it rarely involves intra-abdominal organs [1]. Intestinal lymphangiectasia is characterized by dilatation of intestinal lymphatics [2,3]. The clinical presentations of intestinal lymphangiectasia include pitting edema, chylous ascites, pleural effusion, diarrhea, malabsorption and intestinal obstruction.　Acute peritonitis is a rare presentation, and it may mimic other surgical pathologies [4,5].

An 8-year-old male child presented to the emergency department with periumbilical pain, vomiting and fever. There was no history of tuberculosis or typhoid fever, and no history of trauma or surgery. On examination, he was febrile with temperature of 39°C. The abdomen was distended with diffuse tenderness and guarding. The total leucocyte count was 22,500/mm3. Serum amylase was 23 units/L. Ultrasonography revealed a multiloculated intra-abdominal collection. The presence of severe pain and fever accompanied with clinical features of peritonitis, and sonological evidence of abdominal collection raised the suspicion of appendicular or small bowel perforation with sepsis. X-Ray of the chest and abdomen were unremarkable, there was no evidence of free intra-peritoneal air. In the absence of availability of emergency computed tomography scan, the patient was taken up for emergency laparotomy for the acute abdomen. Laparotomy revealed 150 ml of milky white ascitic fluid and chalky white plaques in the mesentery. A few mesenteric lymph nodes were seen (Fig. 1). The small bowel and the appendix appeared grossly normal. A clinical diagnosis of chylous ascites with dilated mesenteric lymphatics (lymphangiectasia) was made. The chylous fluid was drained and a thorough peritoneal lavage was done. Biopsies were taken from the mesenteric lymph nodes and peritoneum.

Fig. 1 Chalky white plaques in mesentery due to dilated lymphatics (bold arrow). Normal fatty yellow mesentery (lined arrow).

Histopathological report was negative for tuberculosis and malignancy. The ascitic fluid was rich in triglycerides (254 mg/dL) and demonstrated chylomicrons and lymphocytes on biochemical analysis. Culture and gram stain were negative. Serum LDL, HDL and triglyceride values were normal. The postoperative period was uneventful. The abdominal drain was removed on post-operative day 2 with no significant output. He was discharged on a high protein and low fat diet, and was asymptomatic at 1-year post-surgery follow up.

Intestinal lymphangiectasia is classified as primary or secondary, based on the underlying etiology. Primary intestinal lymphangiectasia represents a congenital disorder of mesenteric lymphatics, whereas secondary is associated with diseases like constrictive pericarditis, lymphoma, pancreatitis, trauma, intestinal malignancy, or may be acquired after surgery [6]. Intestinal lymphangiectasia is often associated with chylous ascites which may easily be mistaken as purulent fluid. The most common cause of chylous ascites in the pediatric population is congenital lymphatic malformation, others being malignancy, tuberculosis, trauma, cirrhosis and post-surgery [7]. The principal mechanisms for formation of chylous ascites are related to disruption of the lymphatic system, from any cause.

Dietary long-chain triglycerides are converted into monoglycerides and free fatty acids and absorbed as chylomicrons in the small bowel lymphatic system, which is responsible for high triglyceride content and the milky appearance of lymph. Medium chain triglycerides, constituting approximately one-third of dietary fat, on the other hand, are absorbed directly by the portal venous system, which is the rationale for their use in the conservative management of chylous ascites [7].

Loss of chyle into peritoneal cavity can lead to serious consequences because of the loss of essential proteins, lipids, immunoglobulins, vitamins, electrolytes, and water. In most cases, patients respond to low fat and high protein diet, enriched with medium-chain fatty acids and no surgery is required. It is very important to replenish fluid and electrolyte losses and treat vitamin deficiencies [4]. Emergency exploratory laparotomy is mostly done only in cases with acute chylous peritonitis for a preoperative suspicion of bowel perforation; however, it gives the opportunity to evacuate the peritoneal fluid, wash the abdominal cavity, and in certain cases, treat the cause.

In case of chronic or debilitating ascites associated with poor weight gain, hypoproteinemia and abdominal distension, elective surgical treatment to treat the lymphatic fistula is indispensible. Preoperative lymphangiography or lymphoscintigraphy is helpful in identifying the anatomical location of the leakage or the presence of a fistula in such presentations [8]. In our case, the diagnosis of primary intestinal lymphangiectasia was established by the presence of chylous ascites (rich in triglycerides and chylomicrons), and the classical appearance of white chalky mesentery in the absence of any secondary cause.