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chylous ascites occurring after abdominal surgery is rare but has been reported in certain populations [ 14 ] .
the reported incidence of this condition has varied because it is rare and sometimes asymptomatic [ 14 ] .
if it becomes symptomatic , however , a massive loss of fat / protein - enriched fluid and lymphocytes can cause severe malnutrition and susceptibility to infection , leading to fatality [ 17 ] .
because of its rare occurrence , there is no consensus for management of this potentially lethal complication [ 17 ] .
sporadic case reports showed that total parenteral nutrition ( tpn ) with or without octreotide ( or somatostatin ) was effective for eradicating this condition [ 37 ] .
however , tpn management requires hospitalization and a central venous catheter which is an invasive procedure .
furthermore , treatment with octreotide and/or somatostatin requires close medical vigilance and high medical costs [ 811 ] . here
we present a case of massive chylous ascites occurring after rectal surgery which was successfully treated with an oral fat - free elemental diet ( ed ) in the outpatient clinic .
a 67-year - old man underwent low anterior resection with para - aortic lymphadenectomy for advanced rectal cancer .
early postoperative course was uneventful and the patient was discharged from hospital 10  days after the surgery .
on the routine outpatient visit planned 21  days after surgery , the patient suffered from a severe sense of abdominal fullness and remarkable abdominal distension was noted with 92  cm of abdominal girth measured at the umbilicus .
an emergency abdominal computed tomography ( ct ) scan proved that abdominal distension was caused by massive ascites ( fig .  1 ) .
urgent diagnostic paracentesis showed that the ascites was a white milky fluid containing high levels of triglycerides ( 546  mg / dl ) , leading to a diagnosis of massive chylous ascites .
simultaneous laboratory findings showed severe hypoproteinemia ( total protein 4.5  g / dl , albumin 2.1  g / dl ) and lymphopenia ( white cell count 3000/l , lymphocyte count 150/l ) .
based on sporadic evidence that tpn with or without octreotide was reported to be effective for eradicating chyloperitoneum occurring after abdominal surgery [ 17 ] , emergency admission was offered to the patient but rejected due to social reasons . therefore , an oral fat - free ed ( 30  kcal / kg / day of elental , ajinomoto pharmaceutical co. ltd , tokyo , japan ) was initiated .
oral intake was strictly restricted to elental , water , and sugar / milk - free beverage .
most notably , the sense of abdominal fullness dramatically abated a few days after starting elental .
his abdominal girth decreased to 82  cm and an abdominal ct scan showed no ascitic fluid in the abdomen 42  days after surgery . at that time , hypoproteinemia and lymphopenia improved ( total protein 7.2  g / dl , albumin 4.2  g / dl , white cell count 6300/l , lymphocyte count 2010/l ) .
accordingly , the ed was totally replaced by a normal diet the following day , after which no abdominal distension was noted . as a result , the chylous ascites was successfully treated in the outpatient clinic .
six months after rectal surgery , the patient underwent partial hepatectomy ( s8 segmentectomy ) for liver metastasis originating from the rectal cancer . at that time , no ascitic fluid was seen in the abdomen .
the patient is doing well without evidence of cancer recurrence or chyloperitoneum at 18  months after the initial rectal surgery ( fig . 
no ascitic fluid was seen in the abdomen abdominal computed tomography performed 3  weeks after surgery .
massive ascites was seen in the abdomen abdominal computed tomography performed 7  weeks after the surgery .
chylous ascites is caused by the unrecognized disruption of a major lymphatic channel during lymphadenectomy [ 17 ] .
meticulous and systematic use of ligation or hemoclips before dividing distinguishable lymphatic vessels is essential for preventing this condition , notably in areas such as the para - aortic region where abdominal lymphatic systems converge and lymphatic fistula is apt to occur [ 17 ] .
however , lymphatic vessels are often indistinguishable and thus chylous ascites can not be completely prevented .
therefore , it is very important to establish a treatment strategy for this complication . the choice of treatment for chylous ascites after abdominal surgery ranges from surgery to conservative treatment [ 17 ] .
if the origin of the leak is definitely detected then surgical repair is preferred [ 12 , 13 ] .
however , imaging modalities for lymphatic structure in the abdomen require special instruments , materials , and expertise and are often unreliable [ 17 , 12 , 13 ] .
even if preoperative detection of the leakage site is available , the success rate of surgical repair for chylous ascites or abdominal lymphatic fistula has been reported to be low at approximately 50  % because the anatomy of lymphatic systems in the abdomen is inconsistent unlike in the thorax [ 17 ] . as an initial treatment , therefore
, sporadic case reports showed that tpn with or without octreotide ( or somatostatin ) is promising for this complication [ 17 ] .
however , these treatments require invasive procedures , close medical vigilance , and high medical costs [ 911 ] .
in contrast , oral ed does not require specific instruments or procedures and is available in the outpatient clinic .
elental , which was used in this case , is almost the same formula as vivonex t.e.n .
elental consists of 15  % protein , 83.5  % carbohydrate , and 1.5  % fat ( caloric distribution , % of kcal ) and can provide nearly fat - free enteral nutrition , which does not need nutritional transport via mesenteric lymphatic systems and is therefore reasonable for mitigating chylous ascites [ 17 ] .
furthermore , elental is a completely digested formula and easily absorbed without digestive juice secretion , therefore , seldom causing bowel peristalsis which activates intra - abdominal lymphatic flow [ 1416 ] . from this aspect
, elental is considered superior to a conventional low - fat diet or medium - chain fat diet which requires digestive juice secretion for absorption and causes bowel peristalsis [ 15 , 1416 ] .
therefore , elental is considered markedly beneficial for decreasing intra - abdominal lymphatic flow and nutritionally promoting wound healing to repair disrupted lymph vessels .
it was reported that conservative treatments for symptomatic postoperative chylous ascites required long - term ( reportedly 4090  days ) management to achieve complete recovery [ 17 ] . in our case , this was achieved 28  days after initiating the elental diet .
furthermore , the patient was relieved from the severe sense of abdominal fullness shortly after starting the diet .
when prescribing an oral ed , low compliance was a problem because of its tastelessness ; however , various flavors have become available recently and compliance was reported to have increased .
if oral application is unendurable , feeding via enteral tube is available and considered to be superior in intrinsic safety to tpn .
thus , fat - free ed can be recommended as an initial treatment for chylous ascites occurring after abdominal surgery because it is easy to start , intrinsically safe , and can be performed in the outpatient clinic if oral intake is available .
lacking strong evidence of its effectiveness , however , other treatment modalities such as tpn with or without octreotide must be initiated when ed is ineffective .
furthermore , surgical repair must always be considered ; cases have been reported where conservative management did not cure chyloperitoneum and surgical repair was necessary [ 17 ] .
hence , it should be emphasized that meticulous , tactful , and appropriate management according to the individual case is essential for this rare but significant complication . in conclusion ,
an oral fat - free ed can be recommended as an initial treatment for chylous ascites occurring after abdominal surgery because it is easy to start , intrinsically safe , and available in the outpatient clinic .
chylous ascites occurring after abdominal surgery is rare . despite being potentially critical , 
 there is no definite treatment guideline because of its rarity . here 
 we present a case of massive chylous ascites occurring after rectal surgery which was successfully treated with an oral fat - free elemental diet ( ed ) . 
 a 67-year - old man underwent low anterior resection with para - aortic lymphadenectomy for advanced rectal cancer . 
 early postoperative course was uneventful and the patient was discharged from hospital 10  days after surgery ; however , after discharge , abdominal distension rapidly developed . 
 abdominal computed tomography ( ct ) performed 3  weeks after surgery revealed massive ascites and laboratory findings showed remarkable hypoproteinemia and lymphopenia . 
 urgent diagnostic paracentesis showed the ascites to be a white milky fluid containing high levels of triglycerides ( 564  mg / dl ) , leading to a diagnosis of chyloperitoneum . 
 daily nutrition of the patient was entirely with a fat - free ed ( 30  kcal / kg / day of elental , ajinomoto pharmaceutical co. ltd , tokyo , japan ) . after the initiation of oral elental , abdominal distension , hypoproteinemia , and lymphopenia gradually improved . 
 abdominal ct performed 7  weeks after surgery showed no ascitic fluid in the abdomen , and thereafter a normal diet was initiated . 
 since then , no relapse of chyloperitoneum has been proven . as a result 
 , the chylous ascites was successfully treated in the outpatient clinic .