intrahepatic biliary cystic tumors ( ibcts ) are rare cystic liver neoplasms that reportedly represent 5% of all intrahepatic cystic diseases . ibcts can be divided into two histologic categories : intrahepatic biliary cystadenoma ( ibc ) and intrahepatic biliary cystadenocarcinoma ( ibca ) . with the increasing recognition of ibcts and advancements in imaging modalities , an increasing number of reports addressing these tumors generally , the diagnosis of ibc is based on specific radiological features , such as multilocular cysts , thickened and irregular walls , internal septa , and mural nodules , and satisfying outcomes can be achieved if complete resections are performed . although the clinical features and prognosis of ibcs have been fully illustrated , few reports have focused on the clinical features and prognosis of ibcas because of their rarity . surgical resection is generally considered the main curative treatment for ibcas or suspected ibcas , but controversy exists regarding the prognosis for ibcas . some surgeons have suggested that long - term survival remains unsatisfying even after radical resections and that the prognosis is similar to that associated with cholangiocarcinoma while others have reported satisfying outcomes after complete resection ( i.e. , low mortality and recurrence rates ) . clinicopathologic features reported to be associated with prognosis include male sex , certain tumor growth types , lymphatic invasion , presence of mesenchymal stroma , and surgery type . however , these reports are not consistent with each other , and few of them aimed to assess the prognosis and prognostic factors associated with ibcas . accordingly , in this study , we compared the clinicopathologic features of ibca with those of ibc to identify possible prognostic factors , which were subsequently analyzed along with previously reported prognostic factors using cox proportional hazards regression models . our aim was to clarify the factors that influence the survival of patients treated with surgical procedures . patients with pathologically confirmed ibca , who underwent surgery between january 2000 and february 2014 at the department of hepatobiliary surgery of the chinese people 's liberation army general hospital , were included in this study . their demographics , clinical presentations , liver function tests , tumor markers , radiological characteristics , pathological evaluation , surgical information , and outcomes were reviewed and analyzed . tumor markers included carbohydrate antigen ( ca199 , normal : 0.137 u / ml ) and carcinoembryonic antigen ( cea , normal : 05.0 g / l ) . because patients with ibc have a better prognosis , we also reviewed the data of 41 ibc patients who underwent surgical resection ; we then compared the data between the two patient populations to identify differences . considering the clinicopathologic variables that a significant difference between patients with ibca and those with ibc might be closely related to prognosis , such variables were subsequently analyzed using cox proportional hazards regression models . also included in this analysis were several variables previously shown to be related to ibca prognosis : surgery type , presence of lymphatic invasion , presence of mesenchymal stroma , and tumor growth type . the follow - up period was defined as the interval between the operation date and the patient 's death or the time of last follow - up . statistical analyses were conducted using spss software ( spss inc . , chicago , il , usa ) , version 20.0 , and differences were considered significant when the p < 0.05 . categorical data were compared using chi - square analysis or fisher 's exact test ; continuous data were compared using student 's t - test and the wilcoxon signed rank sum test and were further categorized according to cut - off values determined using receiver operating characteristic ( roc ) curves . univariate and multivariate cox proportional hazards regression models were used to determine associations between clinicopathologic variables and prognosis . variables that showed a significant difference in univariate analysis were subsequently included in a multivariate analysis . survival curves were constructed using the kaplan  meier method and were compared using the log - rank test . thirty - four patients with a mean age of 57.5  10.9 years were included in the study . there was a strong female predominance : totally , 21 patients ( 61.8% ) were women . the most common presenting symptoms were abdominal pain or discomfort ( n = 24 , 70.6% ) , and jaundice was observed in nine patients ( 26.5% ) . six patients ( 17.6% ) were asymptomatic ; their tumors were accidentally detected on routine physical examination . for symptomatic patients , six patients had undergone previous inappropriate treatments because of misdiagnosis ( lesions were diagnosed as simple hepatic cysts or other hepatic cystic lesions ) , including percutaneous transcatheter drainage ( n = 1 ) , laparoscopic fenestration ( n = 2 ) , open fenestration ( n = 2 ) , internal roux - en - y drainage ( n = 1 ) , and partial resection ( n = 1 ) . clinical characteristics of ibc and ibca patients * chi - square test ; student s t - test ; wilcoxon rank sum test . ibc : intrahepatic biliary cystadenoma ; ibca : intrahepatic biliary cystadenocarcinoma ; cea : carcinoembryonic antigen ; alt : alanine aminotransferase ; tbil : total bilirubin ; ca : carbohydrate antigen . laboratory data were available for 32 patients and revealed normal liver function in 11 ; obvious liver dysfunction mostly occurred in patients with obstructive jaundice . tumor marker serum ca19 - 9 levels were available for all patients and were elevated in 14 ; the average value was 1103  4249.8 u / ml . a variety of radiological examinations were performed preoperatively , including computed tomography ( ct ; n = 31 ) , ultrasonography ( n = 17 ) , magnetic resonance imaging ( n = 4 ) , magnetic resonance cholangiopancreatography ( n = 2 ) , and positron emission tomography ( n = 2 ) . ct was the most commonly used imaging modality , and the typical findings associated with ibca included multilocular cysts with thickened and irregular walls ( 30/34 , 88.2% ) , internal septa ( 26/34 , 76.5% ) , and mural nodules ( 29/34 , 85.3% ) . internal septa and mural nodules showed mild or marked contrast enhancement in most patients ( 30/34 , 88.2% ; figure 1 ) . the mean tumor size was 7.1  4.3 cm ; 64.7% of tumors were located in the left liver lobe . ( a ) and ( b ) computed tomography ( ct ) shows intrahepatic biliary cystadenoma in liver segment iv with intrahepatic bile duct dilation due to tumor compression ; thin internal septa were observed in the tumor ; ( c ) and ( d ) intrahepatic biliary cystadenocarcinoma located in the left hepatic lobe with multiple metastases in the right lobe ; internal septa and mural nodules showed mild contrast enhancement on venous phase ct . surgeries were successfully performed in all patients : laparoscopic enucleation ( n = 1 ) , open enucleation ( n = 2 ) , enucleation combined with cholangiojejunostomy ( n = 1 ) , left hemihepatectomy ( n = 6 ) , left hemihepatectomy with t - tube drainage ( n = 2 ) , left bisegmentectomy ( n = 1 ) , left segmentectomy ( n = 7 ) , right hemihepatectomy ( n = 4 ) , right segmentectomy ( n = 4 ) , and partial tumor resection or biopsy ( n = 6 ) . the three patients who underwent partial tumor resection did not receive radical excision because of peritoneal or distant metastasis . perioperative complications occurred in 12 patients and included intra - abdominal abscess ( n = 2 ) , postincision infection ( n = 2 ) , intra - abdominal bleeding ( n = 3 ) , bile leakage ( n = 3 ) , gastrointestinal bleeding ( n = 2 ) , and pleural effusion ( n = 6 ) . only one patient suffering from intra - abdominal bleeding required reoperation ; the other complications resolved with conservative management . follow - up data were available for 31 patients ; the median follow - up time was 39.1  32.7 months ( range , 6123 months ) . three patients were lost to follow - up at 6 , 18 , and 21 months postoperatively , respectively . at the last follow - up , 16 patients had no evidence of disease , two patients survived with the disease , and three patients had undergone reoperation because of tumor recurrence but were still alive . the median overall survival was 76.2 months ; survival at 1 , 3 , and 5 years was 88.0% , 68.7% , and 45.8% , respectively . because patients with ibc who undergo complete resection can achieve a better prognosis than those with ibca , in order to identify prognostic factors for survival , we first compared the clinical characteristics of ibc patients with those of ibca patients to identify risk factors associated with malignancy , considering that clinical variables showing a significant difference might also be factors associated with prognosis . clinical variables showing a significant difference between these two patient populations were sex , mean age , alt , tbil , tumor size , and the presence of mural nodules [ table 1 ] . patients with ibca showed greater elevations in alt ( p = 0.01 ) and tbil ( p = 0.04 ) than those with ibc . serum ca19 - 9 ( p = 0.32 ) and cea ( p = 0.36 ) showed no significant difference . although we did not detect a significant difference in the presence of mesenchymal stroma between patients with ibc and those with ibca , this was identified as an important factor associated with prognosis by previous studies , so we included it in subsequent analyses . other variables , reported to be associated with prognosis by previous studies that is surgical type , presence of lymphatic invasion , and tumor growth type , were also included . according to the cut - off values determined using roc curves , patients were further categorized as 60 years or > 60 years [ figure 2a ] , tumor size as 7.5 cm or > 7.5 cm [ figure 2b ] , tbil as  23.5 mol / l or > 23.5 mol / l [ figure 2c ] , and alt as 98.5 mol / l [ figure 2d ] . in univariate analyses , age ( p = 0.029 ) , surgical type ( p = 0.007 ) , lymphatic invasion ( p = 0.046 ) , and tumor growth type ( p = 0.038 ) all showed significant differences , while sex , tumor size , tbil , alt , presence of mural nodules , and presence of mesenchymal stroma did not [ table 2 ] . however , multivariate analysis found only radical resection ( p = 0.002 ; hazard ratio [ hr ] : 0.079 ; 95% confidence interval [ ci ] : 0.0160.378 ) and noninvasive tumor type ( p = 0.009 ; hr : 0.161 ; 95% ci : 0.0420.629 ) to be independent prognostic factors for survival . ( a ) age ( dead patients vs. live patients ) ; area under the curve ( auc ) : 0.751 ; standard error ( se ) : 0.092 ; p = 0.015 ; sensitivity : 53.8% ; specificity : 90.5% ; ( b ) tumor size ; auc : 0.678 ; se : 0.093 ; p = 0.086 ; sensitivity : 92.3% ; specificity : 57.1% ; ( c ) total bilirubin ; auc : 0.483 ; se : 0.108 ; p = 0.871 ; sensitivity : 16.7% ; specificity : 95.5% ; ( d ) alanine aminotransferase ; auc : 0.593 ; se : 0.103 ; p = 0.377 ; sensitivity : 25.0% ; specificity : 95.5% . univariate analysis of the prognostic factors for survival ( n = 34 ) ci : confidence interval ; alt : alanine aminotransferase ; tbil : total bilirubin ; hr : hazard ratio . for patients who underwent radical resection , the kaplan meier estimated survival rates at 1 , 3 , and 5 years were 84.9% , 72.7% , and 66.1% , respectively . for those who underwent palliative resection , the estimated survival rates at 1 , 3 , and 5 years were 33.3% , 33.3% , and data not available , respectively [ figure 3a ] . the median survival times of patients who underwent radical or palliative resections were 84.4 months and 18.3 months , respectively ; the difference was significant according to log - rank analysis of the kaplan  meier model ( p = 0.002 ) . for patients with noninvasive tumors , the survival rates at 1 , 3 , and 5 years were 90.5% , 77.7% , and 62.1% , respectively ; for those with invasive tumors , the survival rates at 1 , 3 , and 5 years were only 83.9% , 44.1% , and 22.0% , respectively [ figure 3b ] . the median survival times of patients with invasive and noninvasive tumors were 32.4 months and 92.7 months , respectively ; the difference was significant ( p = 0.025 ) . ( a ) overall survival curves for the radical and palliative resection groups ; ( b ) overall survival curves for the invasive and noninvasive tumor types . thirty - four patients with a mean age of 57.5  10.9 years were included in the study . there was a strong female predominance : totally , 21 patients ( 61.8% ) were women . the most common presenting symptoms were abdominal pain or discomfort ( n = 24 , 70.6% ) , and jaundice was observed in nine patients ( 26.5% ) . six patients ( 17.6% ) were asymptomatic ; their tumors were accidentally detected on routine physical examination . for symptomatic patients , six patients had undergone previous inappropriate treatments because of misdiagnosis ( lesions were diagnosed as simple hepatic cysts or other hepatic cystic lesions ) , including percutaneous transcatheter drainage ( n = 1 ) , laparoscopic fenestration ( n = 2 ) , open fenestration ( n = 2 ) , internal roux - en - y drainage ( n = 1 ) , and partial resection ( n = 1 ) . clinical characteristics of ibc and ibca patients * chi - square test ; student s t - test ; wilcoxon rank sum test . ibc : intrahepatic biliary cystadenoma ; ibca : intrahepatic biliary cystadenocarcinoma ; cea : carcinoembryonic antigen ; alt : alanine aminotransferase ; tbil : total bilirubin ; ca : carbohydrate antigen . laboratory data were available for 32 patients and revealed normal liver function in 11 ; obvious liver dysfunction mostly occurred in patients with obstructive jaundice . tumor marker serum ca19 - 9 levels were available for all patients and were elevated in 14 ; the average value was 1103  4249.8 u / ml . a variety of radiological examinations were performed preoperatively , including computed tomography ( ct ; n = 31 ) , ultrasonography ( n = 17 ) , magnetic resonance imaging ( n = 4 ) , magnetic resonance cholangiopancreatography ( n = 2 ) , and positron emission tomography ( n = 2 ) . ct was the most commonly used imaging modality , and the typical findings associated with ibca included multilocular cysts with thickened and irregular walls ( 30/34 , 88.2% ) , internal septa ( 26/34 , 76.5% ) , and mural nodules ( 29/34 , 85.3% ) . internal septa and mural nodules showed mild or marked contrast enhancement in most patients ( 30/34 , 88.2% ; figure 1 ) . the mean tumor size was 7.1  4.3 cm ; 64.7% of tumors were located in the left liver lobe . ( a ) and ( b ) computed tomography ( ct ) shows intrahepatic biliary cystadenoma in liver segment iv with intrahepatic bile duct dilation due to tumor compression ; thin internal septa were observed in the tumor ; ( c ) and ( d ) intrahepatic biliary cystadenocarcinoma located in the left hepatic lobe with multiple metastases in the right lobe ; internal septa and mural nodules showed mild contrast enhancement on venous phase ct . surgeries were successfully performed in all patients : laparoscopic enucleation ( n = 1 ) , open enucleation ( n = 2 ) , enucleation combined with cholangiojejunostomy ( n = 1 ) , left hemihepatectomy ( n = 6 ) , left hemihepatectomy with t - tube drainage ( n = 2 ) , left bisegmentectomy ( n = 1 ) , left segmentectomy ( n = 7 ) , right hemihepatectomy ( n = 4 ) , right segmentectomy ( n = 4 ) , and partial tumor resection or biopsy ( n = 6 ) . the three patients who underwent partial tumor resection did not receive radical excision because of peritoneal or distant metastasis . perioperative complications occurred in 12 patients and included intra - abdominal abscess ( n = 2 ) , postincision infection ( n = 2 ) , intra - abdominal bleeding ( n = 3 ) , bile leakage ( n = 3 ) , gastrointestinal bleeding ( n = 2 ) , and pleural effusion ( n = 6 ) . only one patient suffering from intra - abdominal bleeding required reoperation ; the other complications resolved with conservative management . follow - up data were available for 31 patients ; the median follow - up time was 39.1  32.7 months ( range , 6123 months ) . three patients were lost to follow - up at 6 , 18 , and 21 months postoperatively , respectively . at the last follow - up , 16 patients had no evidence of disease , two patients survived with the disease , and the median overall survival was 76.2 months ; survival at 1 , 3 , and 5 years was 88.0% , 68.7% , and 45.8% , respectively . because patients with ibc who undergo complete resection can achieve a better prognosis than those with ibca , in order to identify prognostic factors for survival , we first compared the clinical characteristics of ibc patients with those of ibca patients to identify risk factors associated with malignancy , considering that clinical variables showing a significant difference might also be factors associated with prognosis . clinical variables showing a significant difference between these two patient populations were sex , mean age , alt , tbil , tumor size , and the presence of mural nodules [ table 1 ] . patients with ibca showed greater elevations in alt ( p = 0.01 ) and tbil ( p = 0.04 ) than those with ibc . serum ca19 - 9 ( p = 0.32 ) and cea ( p = 0.36 ) showed no significant difference . although we did not detect a significant difference in the presence of mesenchymal stroma between patients with ibc and those with ibca , this was identified as an important factor associated with prognosis by previous studies , so we included it in subsequent analyses . other variables , reported to be associated with prognosis by previous studies that is surgical type , presence of lymphatic invasion , and tumor growth type , were also included . according to the cut - off values determined using roc curves , patients were further categorized as 60 years or > 60 years [ figure 2a ] , tumor size as 7.5 cm or > 7.5 cm [ figure 2b ] , tbil as  23.5 mol / l or > 23.5 mol / l [ figure 2c ] , and alt as 98.5 98.5 mol / l [ figure 2d ] . in univariate analyses , age ( p = 0.029 ) , surgical type ( p = 0.007 ) , lymphatic invasion ( p = 0.046 ) , and tumor growth type ( p = 0.038 ) all showed significant differences , while sex , tumor size , tbil , alt , presence of mural nodules , and presence of mesenchymal stroma did not [ table 2 ] . however , multivariate analysis found only radical resection ( p = 0.002 ; hazard ratio [ hr ] : 0.079 ; 95% confidence interval [ ci ] : 0.0160.378 ) and noninvasive tumor type ( p = 0.009 ; hr : 0.161 ; 95% ci : 0.0420.629 ) to be independent prognostic factors for survival . ( a ) age ( dead patients vs. live patients ) ; area under the curve ( auc ) : 0.751 ; standard error ( se ) : 0.092 ; p = 0.015 ; sensitivity : 53.8% ; specificity : 90.5% ; ( b ) tumor size ; auc : 0.678 ; se : 0.093 ; p = 0.086 ; sensitivity : 92.3% ; specificity : 57.1% ; ( c ) total bilirubin ; auc : 0.483 ; se : 0.108 ; p = 0.871 ; sensitivity : 16.7% ; specificity : 95.5% ; ( d ) alanine aminotransferase ; auc : 0.593 ; se : 0.103 ; p = 0.377 ; sensitivity : 25.0% ; specificity : 95.5% . univariate analysis of the prognostic factors for survival ( n = 34 ) ci : confidence interval ; alt : alanine aminotransferase ; tbil : total bilirubin ; hr : hazard ratio . for patients who underwent radical resection , the kaplan meier estimated survival rates at 1 , 3 , and 5 years were 84.9% , 72.7% , and 66.1% , respectively . for those who underwent palliative resection , the estimated survival rates at 1 , 3 , and 5 years were 33.3% , 33.3% , and data not available , respectively [ figure 3a ] . the median survival times of patients who underwent radical or palliative resections were 84.4 months and 18.3 months , respectively ; the difference was significant according to log - rank analysis of the kaplan  meier model ( p = 0.002 ) . for patients with noninvasive tumors , the survival rates at 1 , 3 , and 5 years were 90.5% , 77.7% , and 62.1% , respectively ; for those with invasive tumors , the survival rates at 1 , 3 , and 5 years were only 83.9% , 44.1% , and 22.0% , respectively [ figure 3b ] . the median survival times of patients with invasive and noninvasive tumors were 32.4 months and 92.7 months , respectively ; the difference was significant ( p = 0.025 ) . ( a ) overall survival curves for the radical and palliative resection groups ; ( b ) overall survival curves for the invasive and noninvasive tumor types . intrahepatic biliary cystic tumors are reported to represent only 5% of all intrahepatic cysts of biliary origin , but their actual incidence is likely much higher because patients are sometimes misdiagnosed with simple hepatic cysts or other cystic lesions . in our study , six patients had undergone previous inappropriate treatment because of misdiagnosis . previous studies have shown that complementary imaging modalities may contribute to correct the diagnosis and provide information useful in formulating appropriate treatment strategies . ibcas in our study were mainly located in the left liver lobe , which is consistent with other reports ; this localization may be related to embryonic gallbladder development . the presence of multilocular cysts , thickened and irregular walls , internal septa , mural nodules , and enhancement of internal septa and mural nodules are radiological characteristics of ibca that can be helpful in differentiating them from biliary intraductal papillary neoplasm and simple hepatic cysts . however , distinguishing between ibc and ibca remains difficult because these lesions have similar imaging characteristics [ figure 1 ] . in our study , sex , mean age , alt , tbil , tumor size , and the presence of mural nodules showed a significant difference between patients with ibc and those with ibca . as reported by previous studies , almost all ibcs occurred in middle - aged females ( mean age , 45.4  17.0 years ) , while ibcas tended to occur in older patients ( mean age , 58.7  11.9 years ; p = 0.02 ) and in more male patients ( 13/34 vs. 4/41 ; p = 0.01 ) . most male patients were older than 60 years , which is consistent with studies by wang et al . and sang et al . the older age of ibca patients may support the hypothesis that cystadenomas can undergo malignant transformation into cystadenocarcinomas over a long time . sang et al . thus , ibca should be suspected in an older male patient with such a lesion , especially when typical signs are present , e.g. , multilocular cysts , internal septa , and mural nodules . as with ibc , we did not find tumor size to correlate with symptoms ( 10.7  5.3 cm for symptomatic patients vs. 13.2  6.2 cm for asymptomatic patients ; p = 0.37 ) . adjacent organ compression , intracystic hemorrhage and infection , and biliary obstruction may relate to clinical symptoms ; jaundice is a less common symptom . in our study , jaundice was found in nine patients and was caused by the following : extrinsic compression or invasion by the tumor ( n = 5 ) , biliary thrombi ( n = 3 ) , and viscid intraductal mucin ( n = 1 ) . although patients with ibca had smaller tumors , their serum liver enzyme values were higher than those of patients with ibcs , and the difference was statistically significant . one possible reason for this difference is that cystadenomas tend to be slow - growing and clinically silent , while cystadenocarcinomas are more inclined to invade the adjacent biliary tree or compress surrounding organs . because ibca is more likely to lead to persistent symptoms , earlier medical interventions are more likely to be performed in these patients , which may explain why ibca patients had shorter symptom durations [ table 1 ] and presented with smaller tumors . patients in the ibca subgroup were more likely to have jaundice compared with the ibc subgroup ( 9/31 vs. 3/41 , respectively ) ; this may be another important reason for the elevated hepatic enzymes in these patients ( obvious liver dysfunction was mostly found in patients with obstructive jaundice ) . mural nodules arise from epithelial tissue , as does ductal adenocarcinoma , and are more commonly seen in patients with ibca . martel et al . identified 2 ibcas out of 13 biliary cystic tumors , both of which presented with small foci of malignant cells in mural nodules . mural nodules were more commonly seen among patients with ibca in our study ; although there appears to be an association between these nodules and malignancy , clarification of this relationship requires additional studies involving larger sample sizes and larger pathological specimens . because it is difficult to make a definitive preoperative diagnosis of ibca and because ibc also has malignant potential , complete resection is recommended for any suspected biliary cystadenoma . another main result of our study was that age , surgery type , the presence of lymphatic invasion , and tumor growth type were all related to ibca prognosis while only surgery type and tumor growth type were independent prognostic factors . earlier therapy , such as internal roux - en - y drainage , aspiration , sclerosis , and partial resection , resulted in high rates of recurrence and malignant degeneration ; thus , any patient presenting with liver cyst recurrence after such treatments should be suspected of having a cystadenoma or cystadenocarcinoma . in our study , for patients , who underwent radical resection , the 5-year survival rate was as high as 66.1% . considering the favorable outcomes , it can produce , radical resection with wide margins ( > 2 cm ) of normal liver tissue should be the goal of surgical procedures . cyst enucleation is only recommended when complete resection might jeopardize biliary radicles or vascular structures although satisfactory outcomes can be achieved if the surgical margins are negative . in our study , four patients underwent enucleation ; as of the last follow - up , one patient had died , and the remaining patients were surviving disease - free . in univariate analysis , there was a significant difference in prognosis between patients who had local lymph node metastasis and those who did not . however , only three patients in our study had local lymph node metastasis , and complete resections could not be performed in two of them because of distant metastases and peritoneal metastasis ; these patients died 6 and 9 months postoperatively , respectively . in most patients , the tumor is confined to the cystic lesions or only invades the surrounding hepatic parenchyma , so extended lymph node resection is not warranted . three patients with recurrence underwent reoperations ; at the end of follow - up , only one of these patients had died , and the other two were surviving disease - free . histologically , cystadenomas and cystadenocarcinomas can be divided into two subgroups according to the presence of ovarian stroma between the inner epithelial lining and the outer connective tissue capsule . those with ovarian stroma occur exclusively in women and have an indolent course with a good prognosis , while those without ovarian stroma more frequently occur in middle - aged men and more easily undergo malignant transformation , carrying a poor prognosis . although a previous multi - institutional study concluded that long - term outcomes were associated with the presence of ovarian stroma , our study did not find this to be true in either univariate or multivariate analysis . this may have been because only ibcas were included , so we were unable to differentiate between tumors derived from malignant degeneration of cystadenomas and de novo cancer ; these different origins may influence prognosis . our limited number of cases is another potential explanation , and further investigation is needed . nakajima et al . divided ibcas into two growth types according to clinicopathologic features : noninvasive ( carcinoma cells confined to the cystic lesions ) and invasive ( carcinoma cells extending into the hepatic parenchyma or neighboring organs ) . in their study , patients with noninvasive tumors had a lower recurrence rate and better long - term outcome than those with invasive tumors . we also found noninvasive tumor growth type to be an independent predictor of better outcome . for patients with invasive tumors , 5-year survival was only 22.0% , similar to that of patients with cholangiocarcinoma . thus , close follow - up is recommended for patients with invasive tumors even after radical resection . first , this was a single - center study with a relatively small sample size , thus , additional studies with larger sample sizes or involving multiple medical centers should be performed to confirm our results . second , patients who had undergone surgery in recent years had a relatively short follow - up period , a longer follow - up period may have influenced their prognosis . third , few patients ( 4/34 ) received adjuvant chemotherapy or radiotherapy after surgical procedures . it is unknown whether these treatments influence patient outcomes , and we have little experience with this . in conclusion , patients with ibca were older , and more males were represented compared with ibc . ibcas more commonly led to liver dysfunction and were more frequently associated with mural nodules . radical resection and noninvasive tumor type are independent prognostic factors for overall survival ; accordingly , complete resection is recommended for curative treatment , and patients should be closely followed postoperatively , particularly those with invasive tumors .
background : surgical resection is generally considered the main curative treatment for intrahepatic biliary cystadenocarcinoma ( ibca ) or suspected ibcas , but controversy exists regarding the prognosis for ibcas . 
 this study aimed to describe the clinicopathological characteristics of ibca and identify prognostic factors that may influence the survival of patients treated with surgical procedures.methods:thirty-four patients with histologically confirmed ibca treated between january 2000 and june 2014 were included . 
 the clinical characteristics of patients with ibca were compared with those of 41 patients with intrahepatic biliary cystadenoma ( ibc ) ; factors that significant difference were analyzed for prognosis analysis of ibca using multivariate / univariate cox proportional hazards regression models . 
 survival curves were constructed using the kaplan  meier method and compared using the log - rank test.results:ibcas had a strong female predominance , and the most common presenting symptoms were abdominal pain or discomfort . compared with ibcs , ibcas occurred in older patients , in more male patients , and were associated statistically significant abnormal increase in alanine aminotransferase ( p = 0.01 ) and total bilirubin ( p = 0.04 ) . 
 mural nodules were more frequently seen with ibcas and may associate with malignancy . 
 it was difficult to differentiate between ibc and ibca based on laboratory examination and imaging findings . 
 although complete resection is recommended , enucleation with negative margins also achieved good outcomes . 
 median overall patient survival was 76.2 months ; survival at 1 , 3 , and 5 years was 88.0% , 68.7% , and 45.8% , respectively . 
 radical resection and noninvasive tumor type were independent prognostic factors for overall survival.conclusions:it remains difficult to distinguish between cystadenomas and cystadenocarcinomas based on laboratory examination and image findings . 
 complete resection is recommended for curative treatment , and patients should be closely followed postoperatively , particularly those with invasive tumors .