malignant cystic neoplasms are rare entities that account for only 1% of all pancreatic tumors.1 serous and mucinous cystic neoplasms are tumors of the exocrine pancreas with different biological behaviors . mucinous cystic tumors are typically slow - growing but carry a significant potential for malignancy , and thus , resection is often indicated.2,3 in contrast , serous cystadenomas are considered benign tumors with almost no malignant potential . they are often observed with serial imaging or managed expectantly.4 in the absence of symptoms , surgery is not usually recommended . the first case of a pancreatic serous cystadenocarcinoma was reported by george et al . in 1989 . the authors described the malignant characteristics of a serous cystic tumor of the pancreas with invasion into the spleen , stomach , and liver . the patient expired intra - operatively due to hemorrhage.5 subsequently , additional reports have documented similar findings of serous cystic neoplasms with malignant behavior . the histological characteristics of serous cystadenocarcinoma are indistinguishable from its benign counterpart , making the presence of invasion the sole distinguishing characteristic between the two.5 in this report , we present a case of serous cystadenocarcinoma with duodenal , vascular , and neural invasion . we also review the literature and discuss the current diagnostic techniques and principles of management . a 70-year - old man presented with upper gastrointestinal ( gi ) bleeding and abdominal pain . there was a duodenal ulcer with no evidence of malignancy on esophagogastroduodenoscopy ( egd ) , and an abdominal computed tomography ( ct ) scan revealed a 5.7-cm cystic mass in the head of the pancreas which was diagnosed by core needle biopsy as a serous cystadenoma . the patient was treated for presumed duodenal ulcer disease leading to resolution of symptoms and scheduled for observation of his pancreatic mass . three months later , the patient returned with recurrent coffee - ground emesis and abdominal pain . ct scan showed enlargement of the pancreatic mass to 6.5    8  cm and central dystrophic calcifications with new pancreatic and biliary ductal dilatation ( fig .  1 ) . repeat egd identified a bleeding duodenal ulceration , and biopsies were consistent with a  benign 1contrast - enhanced ct scan demonstrating a large mass measuring 6.5    8  cm in the head of the pancreas ( arrow ) with central dystrophic calcifications . contrast - enhanced ct scan demonstrating a large mass measuring 6.5    8  cm in the head of the pancreas ( arrow ) with central dystrophic calcifications . upon surgical consultation , an elective pancreaticoduodenectomy was planned due to the increased size of the tumor , recurrent bleeding , and erosion into the duodenum . laparotomy revealed a large mass in the head of the pancreas with no evidence of gross metastatic disease or invasion of the mesenteric vessels . the patient s post - operative course was complicated by delayed gastric emptying requiring temporary gastrostomy and feeding jejunostomy tubes . on gross examination , the mass measured 9    8    6  cm , and there was marked , aggressive invasion of the duodenum beyond the level of the muscularis propria ( fig .  2 ) . microscopic vascular and perineural invasion were also seen , further distinguishing this lesion from a benign serous cystadenoma ( figs .  4 and 5 ) . note invasion of the duodenum through the muscularis propria and submucosa with ulceration of the overlying mucosa ( arrow).fig . the tumor is composed of multiple cysts lined by cuboidal cells with clear cytoplasm.fig . note invasion of the duodenum through the muscularis propria and submucosa with ulceration of the overlying mucosa ( arrow ) immunochemical stains for keratin ae1/3 , 7 , and 19 and cam 5.2 were positive . stained samples of the mass also showed weak immunoreactivity for carcinoembryonic antigen ( cea ) . at last follow - up 7  years post - operatively , the patient is doing well without clinical or radiographic evidence of recurrent disease . literature review yielded 25 reports of serous cystadenocarcinoma ( table  1).523 the average age at presentation is 68    2  years , and 60% of patients affected are female ( 28% male ; in 12% of cases , sex was not reported ) . presenting complaints included abdominal pain ( 24% ) , upper gi bleeding ( 12% ) , weight loss ( 8% ) , palpable mass ( 8% ) , jaundice or abnormal serum liver enzymes ( 8% ) , and nonspecific abdominal complaints ( 8% ) . table  1characteristics of pancreatic serous cystadenocarcinoma reported in the literatureauthorpublication yearpatient agepatient gendersigns / symptomstumor size ( cm)metastasesprocedureoutcomenotegeorge et al.5198970mhemorrhage from gastric varices11synchronous in stomach and liverdpoperative death due to hemorrhagefriedman6199074fna19    16    10synchronous in liver , lungs , bone marrow , adrenal glands , lnnanakamei et al.7199172fjaundice10nototal pancreatectomynaokada et al.8199163fabdominal pain12metachronous in liverdpalive 1 year lateryoshimi et al.9199263fabdominal pain12metachronous in liverdpalive 3 years laterohta et al.10199364murinary frequency2.5    2.5    2noenucleationalive 9 months laterwidmaier et al.11199671mabnormal liver function4synchronous in lnpylorus - preserving partial pancreatico - duodenectomyalive 1 year laterishikawa et al.12199863fabdominal pain12metachronous in liverdpnasiech et al.131998nanananananana2 cases reportederiguchi et al.14199865fpalpable abdominal mass16synchronous and meta - chronous in liverdp , microwave coagulo - necrotic therapyalive 10 years laterabe et al.15199871fpalpable abdominal mass12    8.5    5synchronous in lndp , splenectomyalive 2 years laterschmidt - rohlfing et al.16199852742 m , 2 fnanananana4 cases reportedkimura and makuuchi17199953 , 66f , mna5 , 3nonana2 cases reportedhorvath and charbot18199981fna6nananawu et al.19199957fhematemesisnasynchronous and meta - chronous in livernanastrobel et al.20200156fabdominal pain , weight loss14    7    4metachronous in liverpylorus - preserving total pancreatico - duodenectomyalive 3 years latershintaku et al.22200585ffatigue , intermittent diarrhea12    9    7direct extension to spleendistal gastrectomy , dpalive 10 months laterfriebe et al.21200580fabdominal pain , anorexia , weight loss8    7    7direct extension to spleendp , splenectomyalive 1 year latergalanis et al.232007nanananasynchronous and meta - chronous lesion in livernana2 cases reportedcurrent70mhematemesis , abdominal pain9    8    6direct extension to duodenumppwalive 7 years laterdp distal pancreatectomy , na not available , ln lymph node , ppw pylorus - preserving whipple resection characteristics of pancreatic serous cystadenocarcinoma reported in the literature dp distal pancreatectomy , na not available , ln lymph node , ppw pylorus - preserving whipple resection the mean diameter of serous cystadenocarcinoma was 10    1  cm ( range , 2.519  cm ) . lesions exhibit both of the hallmarks of malignancy : local invasiveness and distant metastasis with most tumors associated with local invasion of the spleen ( 8% ) , small intestine ( 4% ) , stomach ( 4% ) , adrenal gland ( 4% ) , or microscopic invasion of vascular and neural tissues . synchronous or metachronous liver metastases were frequently noted ( 36% ) , along with metastasis to regional lymph nodes ( 12% ) , bone marrow ( 4% ) , and lung ( 4% ) . mean survival was 36    11  months ( range , < 30  days to 120  months ) among cases with follow - up ( n  =  11 ) , and ten ( 91% ) of these patients were still alive when reports were published including seven ( 64% ) patients with metastatic disease . indeed , the correct diagnosis of serous cystadenocarcinoma was not made pre - operatively in any of the cases , including the current one.523 the benign and malignant variants appear identical histologically , with the only distinguishing feature being gross or microscopic evidence of invasiveness . thus , the utility of cytology or histology obtained from core needle biopsy is limited.18 the current practice for management of serous cystadenomas of the pancreas is to observe asymptomatic lesions thereby avoiding the potential morbidity and mortality associated with a major operation.13,14,18,24,25 we agree with this conservative approach . nevertheless , clinicians should be aware of the possibility for malignant transformation in serous cystic neoplasms and should maintain an index of suspicion when certain clues appear . these include the onset of new symptoms , worsening of symptoms , or rapid enlargement of the mass . in these cases , resection may be indicated , despite the lack of objective evidence for malignancy obtained from preoperative imaging , endoscopy , and biopsies . in the current case , a serous cystadenocarcinoma was diagnosed without evidence of distant metastasis but with extensive tumor invasion into surrounding structures , both grossly and microscopically . to our knowledge , this is the first example of serous cystadenocarcinoma with extensive duodenal , vascular , and neural invasion but no distant metastases . our case report is illustrative of the management strategy for serous cystic lesions of the pancreas despite the presence of an initially unrecognized malignancy : the progression of symptoms and increase in size of the mass triggered curative resection . the excellent prognosis associated with serous cystadenocarcinoma justifies an aggressive approach to surgical resection , even in older patients . this is especially so since major pancreatic resections are now done with very low mortality and morbidity rates in major centers around the world.26
backgroundserous cystic neoplasms of the pancreas are benign lesions with little chance for malignant degeneration . 
 we report a case of malignant serous cystadenocarcinoma of the pancreas and review the literature.methodsstructured review of the literature was performed using pubmed and medline searches , and cases of serous cystadenocarcinoma of the pancreas were compiled.resultsa 70-year - old man diagnosed with a serous cystadenoma was managed expectantly until he became symptomatic , and studies revealed an increase in the size of the lesion as well as duodenal invasion . 
 the patient underwent a pancreaticoduodenectomy , and histopathological examination revealed a locally invasive cystadenocarcinoma without metastatic disease . 
 seven years later , the patient remains disease - free . 
 review of the literature identified 25 cases of serous cystadenocarcinoma published to date . 
 the mean age at diagnosis is 68    2  years ( range , 52 to 81 ) , and women are affected more commonly ( 2:1).conclusionswe conclude that there is a small but finite risk of malignancy for serous cystic neoplasms of the pancreas . 
 the clinician should bear this in mind when faced with decisions regarding patient management . 
 prognosis is excellent with multiple reports of long - term survival even in the face of metastatic disease .