You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
an increase in cellular proliferation is associated with a reduced rate of apoptosis , while morphological features include hyperchromasia and pleomorphism .
dysplasia is classified histopathologically as either low- or high - grade according to the degree of cytological abnormalities and cellular pleomorphism .
as dysplastic cells do not invade the basement membrane , the term  in situ neoplasia is often used synonymously and is considered a pre - cancerous state . in general ,
dysplasia is typically detected incidentally or as part of a screening investigation . with regard to ductal dysplasia , abnormalities , whether they be clinical , biochemical or radiological , will only be detectable if the lesion begins to occlude the lumen of the duct and therefore disrupt the normal function . in the context of the biliary ducts , disruption of normal luminal flow of bile
bile ductal dysplasia may represent a risk factor for the development of an invasive neoplasm at the same site . in this case , early detection of dysplastic cells at the duct margins , for example following a routine cholecystectomy , would allow more radical surgery to be performed early .
secondly , ductal dysplasia may be a risk factor for the development of malignancy at another site within the ductal tree , suggesting predisposition to neoplastic transformation as a field event .
lastly , and more commonly , ductal dysplasia is seen as a local extension of an existing invasive cancer .
observational studies have shown that high - grade cystic duct dysplasia is present at the margins of resected cholangiocarcinomas in up to 13% of cases .
importantly , however , this appears to have no effect on overall survival , although there are higher rates of recurrence in long - term survivors .
a 67-year - old gentleman was referred to the hepatobiliary surgical team after presenting to his general practitioner with features of obstructive jaundice - associated anorexia and weight loss of approximately 10 kg over a period of several months .
initial blood tests revealed a picture indicative of biliary obstruction : a raised serum bilirubin of 93
mol / l , a serum aspartate aminotransferase ( ast ) of 50 iu / l and a serum alkaline phosphatase ( alp ) of 454 iu / l .
an ultrasound scan confirmed biliary obstruction characterised further by a ct scan as an intraluminal filling defect within the mid common bile duct ( fig .
cellular brushings obtained during endoscopic retrograde cholangiopancreatography and biliary stenting demonstrated high - grade dysplastic cells but no evidence of invasive malignancy . following a multi - disciplinary team meeting a provisional diagnosis of cholangiocarcinoma
was made and the patient underwent pylorus - preserving pancreatoduodenectomy with roux - en - y reconstruction , pancreatojejunostomy , hepaticojejunostomy and gastrojejunostomy .
histological examination of the surgical specimen however did not reveal invasive malignancy but rather two foci of high - grade biliary dysplasia in the cystic duct and in the intrapancreatic segment of the common bile duct ( fig .
the post - operative period was complicated by a low - volume pancreatic leak which led to sepsis .
the patient 's blood results were as follows : a haemoglobin ( hb ) level of 8.5 g / dl , a white cell count of 21.3  10/l , a neutrophil count of 18.1  10/l and a platelet count of 293  10/l .
mol / l , an ast of 45 iu / l and an alp of 63
these post - operative complications necessitated an in - patient stay of nearly 3 weeks .
the patient was discharged with a normal full blood count and normalising liver function tests .
one week post - discharge the patient presented to the emergency department with haematemesis and collapse . on examination he was haemodynamically unstable with a hb level of 5 g / dl and platelets of 113  10/l .
he was transfused with packed red blood cells , platelets and coagulation products and managed on the intensive care unit .
angiogram revealed a gastro - duodenal artery stump haemorrhage , which was treated with a covered stent over the origin of the gastro - duodenal artery ( fig .
subsequently , for the first time , the patient manifested with bile leak from the old drain site .
this was treated with a retrievable covered stent across the hepaticojejunostomy under percutaneous transhepatic cholangiography ( fig .
1d ) , ct - guided drainage of the collection and broad - spectrum antibiotics .
he did not undergo surveillance or chemotherapy as no invasive cancer was diagnosed . after an uneventful and complication - free period of 14 months , the patient presented to the emergency department with jaundice and biliary sepsis .
a ct scan revealed a large 9-cm central soft tissue mass in segment v / viii of the liver , at the confluence of the right and left biliary trees , and multiple smaller liver lesions , an appearance highly suggestive of metastatic disease ( fig .
however , no evidence of malignancy was obtained from a targeted ultrasound - guided liver biopsy and the patient was therefore treated with antibiotics , percutaneous transhepatic cholangiogram and biliary drains ( fig .
repeat ct showed no change in appearance of the liver lesions , therefore ruling out abscess .
after nearly 2 months following the previous biopsy , the patient attended electively for a check cholangiography , repeat biliary stenting and a repeat liver biopsy .
this biopsy showed moderately differentiated adenocarcinoma , in keeping with a metastatic cholangiocarcinoma ( fig .
re - assessment of pancreatico - duodenectomy specimen with multiple levels failed to reveal any focus of invasive cancer . on follow - up assessments the patient 's liver function tests continued to deteriorate , with a bilirubin of 234 mol / l , an alanine aminotransferase of 80
iu / l , an ast of 200 iu / l , an alp of 364 iu / l and a gamma - glutamyl transferase of 563 iu /
considering that a tissue diagnosis of malignancy was eventually made , it may be worth delineating the potential relevance of the original presence of cystic duct dysplasia .
the cystic duct dysplasia may have either represented a pathological state from which the eventual adenocarcinoma directly originated or one which shared common risk factors , such that the presence of dysplastic cells forecasts the development of malignant cells at an independent site .
as the pylorus - preserving pancreatoduodenectomy specimen showed no malignant cells , it is unlikely that the cystic duct dysplasia represented a local extension of an existing carcinoma .
there is very little literature on the prevalence , aetiology or management of cystic duct dysplasia and the associated incidence of cholangiocarcinoma .
bile duct carcinoma is frequently associated with dysplasia and is multifocal in 10% of cases .
cystic duct dysplasia may therefore be associated with an underlying bile duct carcinoma . to date
, only one case series has been published interrogating the presence of cystic duct dysplasia in the absence of existing carcinoma .
this study identified only 4 patients with cystic duct dysplasia from a total of 193 who underwent cholecystectomies with cancer - free specimens . a recent study from our institution demonstrated that up to 2.8% of patients might have incidental gall bladder dysplasia or carcinoma .
the risk factors for the development of cystic duct dysplasia remain incompletely understood much the same as invasive cholangiocarcinomas .
several studies have suggested that hepatitis c virus and alcohol may represent aetiological factors . we have suggested that gall bladder dysplasia is more common in older patients and those with asian ethnicity .
for example , expression of the oncofetal protein imp3 ( insulin - like growth factor ii mrna - binding protein 3 ) was found to correlate with increased tumour aggressiveness and reduced overall survival .
the case presented above posed several dilemmas regarding management decisions , including management of complications post - pancreatico - duodenectomy and surveillance of patients with dysplasia .
the authors suggest a tailored approach for each patient in the absence of any longitudinal case - control or cohort studies . currently there is no evidence for chemotherapy for dysplasia in the absence of invasive malignancy . based on clinical experience and the few published reports available , cystic duct dysplasia is certainly a rare condition , but one that warrants further investigation .
it is worth noting that , despite the progression of pathology demonstrated in the above case and although dysplasia is generally considered a precursor to malignancy , not all dysplastic lesions ultimately develop malignancy .
a small minority may remain unchanged in size for years and yet others may even disappear .
the authors suggest that high - grade biliary dysplasia be put on a surveillance programme in much the same way as invasive cholangiocarcinoma . if all the clinical and radiological clues point towards malignancy , treatment such as chemotherapy should be initiated even if a histological diagnosis can not be confirmed .
cystic and bile duct dysplasia is a rare histological finding , especially when found in the absence of an underlying malignancy . 
 we report a patient who presented with jaundice and weight loss . 
 clinical and cytological evidence suggested a diagnosis of cholangiocarcinoma and the patient underwent a pancreatico - duodenectomy . 
 histopathological examination suggested a diagnosis of two foci of biliary dysplasia : cystic duct and lower common bile duct . 
 fifteen months later , the patient re - presented with signs of obstructive jaundice and biliary sepsis . 
 although ct scan revealed images highly indicative of metastatic disease , repeated biopsies failed to confirm this . 
 eventually a liver biopsy did reveal moderately differentiated adenocarcinoma , however oncological interventional was no longer appropriate and the patient was managed palliatively . 
 this case report focuses on the current understanding of progression of biliary dysplasia .