biliary cystadenomas are rare cystic lesions of the liver . they account for less than 5% of nonparasitic cysts of the liver   and occur frequently in middle - aged women . these cysts need to be differentiated from other cystic lesions such as simple cysts , hydatid cysts , abscesses , hematomas , and polycystic liver disease . biliary cystadenomas were first described in 1943 ; less than 200 cases have been reported till date . they are often benign lesions with a malignant potential [ 3 , 5 , 6 ] . they develop from either an aberrant bile duct or directly from a primitive hepatobiliary stem cell [ 1 , 7 , 8 ] . majority are intrahepatic ( 85% ) [ 6 , 7 , 911 ] , fewer are extra hepatic [ 57 , 12 ] and occasionally are seen to arise from the gall bladder [ 9 , 12 ] . there is difficulty in differentiating a benign from a malignant biliary cystadenoma and hence these lesions should always be resected . one can not always reliably distinguish a simple cyst or a hydatid cyst from a benign biliary cystadenoma . in such situations , deroofing , marsupialization , or partial resection of the suspected cysts has resulted in a very high rate of recurrence ( > 90% ) . we report a series of 13 cases highlighting the radiological interpretation of biliary cystadenomas , issues on surgical management , and postoperative followup for recurrence . records of patients with histologically confirmed biliary cystadenomas admitted between march 2006 and october 2011 at the institute of surgical gastroenterology and liver transplantation , government stanley medical college , chennai , india , were reviewed retrospectively . patients ' charts were scrutinized for demographic characteristics , clinical presentation , radiological findings , and past and present surgical details and outcomes like morbidity and mortality . preoperative diagnosis on ultrasound and cect abdomen was based on presence of one or more findings of internal septations , mural nodules , papillary projections , and cyst wall enhancement ( figure 1 ) . the choice of surgical procedure was based on the site and size of the lesion . liver resection was the preferred procedure and enucleation was done when resection was not feasible . of the 13 patients with biliary cystadenomas , there were eleven women and two men . the most common symptom was abdominal pain ( 92% ) , followed by abdominal distension , loss of appetite , and mass abdomen . the median duration of symptoms was 18 months ( range 2 to 42 months ) . out of seven patients with history of previous surgery for liver lesions , five patients had partial cystopericystectomies done elsewhere for suspected hydatid cyst , one patient had a laparoscopic marsupialisation and one had laparoscopic fenestration , the latter two for presumed simple cyst of the liver . all seven patients had recurrence of symptoms after a median interval of 4 years ( range 2 months to 5 years ) . four patients had the postoperative biopsy report as intrahepatic biliary cystadenoma and in three , the histology was inconclusive . typical findings included multiloculated cyst with a well - defined capsule , some with wall calcification , internal septations , and solid papillary projections . three patients had elevated serum gamma glutamyl transferase and serum alkaline phosphatase ( table 1 ) . ten of the 13 patients had resection of the involved segments : four hepatectomies , three bisegmentectomies , two lateral segmentectomies , and one extended right hepatectomy ( figures 2 and 3 ) . in 3 patients , proper hepatic resection could not be performed owing to the large size of the lesion ( longest diameter ranging from 23  cm to 34  cm ) and the close proximity to the hilum , indenting the hilar structures . hence enucleation was contemplated in these patients with a view to relieve the symptoms ( figure 5 ) . eventually , the histopathology in these three patients turned out to be benign . t - tube placement was done in 2 of these patients in whom the cyst had a communication with the bile duct . the preoperative imaging had not demonstrated this biliary communication . a leak test done after enucleation had demonstrated bile leak in the enucleation bed . the site of leak was suture ligated with a t - tube drainage of the common bile duct . the t - tube was removed two weeks later , after confirming absence of a bile leak . both these patients were free of biliary sequelae or other complications in the followup period of 8 and 14 months . postoperatively , one patient developed basal atelectasis of the left lung , which settled with supportive care and one patient developed a subdiaphragmatic collection for which ultrasound guided pigtail drainage was done . none of the patients had recurrence of symptoms or recurrence of the cyst during a median followup of 22 months ( range 3 to 66 months ) . the three patients in whom the lesion was enucleated were specifically followed up with regular usg abdomen even if asymptomatic , which demonstrated no recurrence . biliary cystadenomas constitute less than 5% of cystic lesions of the liver . typically , the patient is a middle - aged woman presenting with abdominal pain and/or discomfort , with distension and a palpable mass [ 1 , 6 , 7 , 14 ] . rare presentations include vomiting , dyspepsia , anorexia , and weight loss [ 14 , 15 ] . acute presentation is often pain due to intracystic hemorrhage or rupture of the cyst and fever secondary to infection of the cyst . jaundice [ 1719 ] is either due to an extrinsic compression of the bile duct , biliary obstruction by an intraluminal tumoural mass , or accretion of mucus secretion from a communicating biliary cystadenoma . ascites is secondary to compression of the inferior vena cava or the hepatic veins [ 19 , 21 , 22 ] . cystadenomas are known to increase in size during pregnancy and following oral contraceptives suggesting hormonal dependency [ 1 , 2 , 13 ] . recurrence of a cyst following partial resection should raise a suspicion of cystadenoma . in our series , abdominal pain was the most common presentation followed by abdominal distension , anorexia and mass abdomen . none of our patients had obstructive jaundice , but three patients had elevated liver enzymes ( table 1 ) . biliary cystadenomas are usually large multiloculated cystic tumours and are of two types : those with [ 1 , 5 , 8 ] , and those without mesenchymal ( ovarian - like ) stroma . the ovarian - like stroma is thick consisting of compact spindle - shaped cells and supports the epithelium and is often seen exclusively in women [ 1 , 7 , 16 ] . microscopically the loculi are limited by single layer of cuboidal or nonciliated columnar epithelium resting on a basement membrane ( figure 6 ) . at places the epithelium forms multiple polypoidal or papillary projections . cystadenomas with mesenchymal stroma are considered premalignant with a good prognosis while those without are known to transform to malignancy more often   with a poor prognosis [ 6 , 8 , 9 ] . the majority of biliary cystadenomas do not communicate with the bile ducts , but luminal communication may be occasionally observed [ 2 , 24 ] . in some of the cases , this variant is considered an intraductal papillary neoplasm with prominent cystic dilatation of the duct rather than a true biliary cystic neoplasm [ 24 , 25 ] . ct and mri often fail to identify the narrow communication   which is easily demonstratable during an intraoperative cholangiogram . the cystic fluid may be clear and mucinous [ 5 , 7 ] . blood stained fluid within the cyst indicates a malignant component ( cystadenocarcinoma ) . rarely , the fluid may be bile stained , purulent , proteinaceous , or gelatinous . differential diagnosis of cystadenomas include simple liver cysts , parasitic cysts ( particularly hydatid cyst ) , haematomas , post - traumatic cysts , liver abscess , polycystic diseases biliary cystadenocarcinoma , and metastatic , ovarian , or pancreatic adenocarcinoma [ 9 , 10 , 14 ] . diagnosis of biliary cystadenomas is often possible on an ultrasonography , cect , and mri abdomen ( figure 4 ) . on ultrasound , cystic nature of the lesion with multiple loculi , septations , and internal echoes , with papillary projections [ 9 , 15 ] , is typical . the cyst is well - demarcated and thick - walled , globular or ovoid with a noncalcified wall [ 79 , 27 ] . cect in addition demarcates the anatomic relation to surrounding structures , particularly major vessels [ 14 , 15 , 28 , 29 ] . mri is able to characterise the nature of fluid within the cyst [ 9 , 28 ] , that is , blood versus mucin . despite all the aforementioned radiological features , the preoperative radiological diagnostic accuracy may be as low as 30% and therefore a high index of suspicion is indicated . an irregular thickness of the cyst wall , presence of mural nodules , or papillary projections indicates the possibility of a malignancy [ 9 , 10 , 28 , 32 ] . well - defined capsule was seen in eight patients ( 61% ) and wall - enhancement in five patients ( 38% ) . papillary projections and calcifications were seen in three patients each . a preoperative core needle biopsy to detect malignancy is not recommended as this is not accurate and carries the risk of needle seeding and dissemination [ 16 , 34 , 35 ] . elevated cea and ca 19 - 9 in the serum or the cystic fluid aids in diagnosis and followup of patients [ 16 , 36 ] . a normal level does not exclude a biliary cystadenoma ; some simple liver cysts may also show elevated serum or cystic fluid cea or ca 19 - 9 . one is the incomplete excision of the cyst , misdiagnosed as a simple cyst or a hydatid cyst , resulting in recurrence and the second is the difficulty in differentiating biliary cystadenomas from biliary cystadenocarcinomas [ 1 , 5 , 9 , 12 ] , either before or during surgery . hence the recommendation is a complete resection of any suspected biliary cystadenoma [ 1 , 5 , 12 ] . in our series , five patients presented to us with recurrence after partial resection done elsewhere for a mistaken diagnosis of hydatid cyst and two patients with recurrence after surgery for a suspected simple liver cyst . earlier , biliary cystadenomas have been treated with various procedures like marsupialization , internal roux - en - y drainage , aspiration , sclerosis , or partial resection . however , all these procedures have been associated with high rates of recurrence [ 7 , 9 , 14 , 37 , 38 ] . this procedure is a valid alternative where resection is difficult or is likely to be associated with morbidity [ 12 , 16 ] . in conclusion , the diagnosis of biliary cystadenoma should be considered in any multilocular cystic lesion of the liver , particularly in a middle - aged woman . it is an important differential diagnosis for a hydatid cyst especially in endemic regions and a complete resection of the cyst is recommended when in doubt . the recommended treatment of choice for any suspected biliary cystadenoma is resection as it is extremely difficult to differentiate preoperatively , a benign from a malignant neoplasm . enucleation is another option and is indicated where resection is impossible due to the size and location of the tumour .