Abstract
Case series summary
This case series describes the postoperative ultrasonographic findings in six cats that underwent a cholecystoduodenostomy as treatment for extrahepatic biliary obstruction. The surgery site was identified in all six cats, most often within the right cranial abdomen as a thick-walled gall bladder, with a broad-based connection to the descending duodenum. Postoperatively, the biliary tree often remained distended, similar to its preoperative appearance. Recurrent extrahepatic biliary obstruction was suspected in three cats with worsening hyperbilirubinemia. Common bile duct distension was progressive in one of these cats and unchanged in another, but improved in the third. Intrahepatic bile duct distension resolved in one cat following surgery but reappeared with suspected recurrent biliary obstruction. In two cats, progressive echogenic biliary contents were associated with locally aggressive cholangiocarcinoma. Our findings suggest that in cats with cholecystoduodenostomy and progressive increases in hyperbilirubinemia following surgery, progressive or recurrent biliary distension and/or progressive echogenic biliary contents should prompt further investigation.
Relevance and novel information
Biliary diversion surgery in cats is associated with high morbidity and mortality. The ultrasonographic appearance of a postoperative cholecystoduodenostomy site has not been described, making differentiation of the expected appearance from postoperative abnormalities difficult. The goal of this study was to determine the expected ultrasonographic appearance, in order to assist in managing cats with recurrent, persistent or worsening clinical signs and biochemical abnormalities following surgery.
Introduction
The most common causes of extrahepatic biliary obstruction (EHBO) in the cat include neoplasia or inflammation of the hepatobiliary system, pancreas and/or duodenum, and cholelithiasis.1–4 Biliary decompression is key to treatment and biliary diversion via cholecystoduodenostomy is the surgical treatment of choice when patency of the common bile duct (CBD) cannot be re-established.1,4 Unfortunately, this procedure is associated with a high perioperative and postoperative morbidity and mortality.1,2,4
Abdominal ultrasonography is instrumental in the diagnosis of EHBO,2,5 and could be equally important for evaluation of cats with recurrent, persistent or worsening clinical signs and biochemical abnormalities following cholecystoduodenostomy. The goal of this case series is to describe the ultrasonographic features of postoperative cholecystoduodenostomy sites in order to aid in differentiation of the expected appearance from abnormal findings. The ultrasound examinations of six cats presented to the Foster Animal Hospital at Cummings School of Veterinary Medicine at Tufts University from 2014 to 2019 were reviewed. The signalment, presentation and outcome for each case is summarized in Table 1. Table 2 provides a timeline of major postoperative ultrasound examination findings, as well as changes in serum total bilirubin for each case.
General patient information
Patient was discharged with a plan to euthanize but was lost to follow-up
Concurrent pancreatic neuroendocrine tumor diagnosed at necropsy
EHBO = extrahepatic biliary obstruction; FS = female spayed; DLH = domestic longhair; DSH = domestic shorthair
Timeline of ultrasound findings and serum total bilirubin values
Normal <1 mm
Normal <5 mm
Reference interval 0.1–0.3 mg/dl
0 indicates the immediately preoperative ultrasound examination
This information is not available as there was a large gap of time between the preoperative ultrasound examination and surgery
Ultrasound examinations following the first year after surgery (from 416 days postoperatively to 1078 postoperatively) have been summarized
GB = gall bladder; CBD = common bile duct; Y = yes; N = no; EHBO = extrahepatic biliary obstruction; NA = not available
Case series description
Case 1
A 14-year-old spayed female domestic longhair cat was diagnosed with EHBO based on acutely progressive hyperbilirubinemia and ultrasound findings consistent with obstructive choledocholithiasis. An exploratory laparotomy was performed, and the CBD was flushed of stones and sludge via a choledochotomy. A cholecystoduodenostomy was performed to prevent recurrent obstruction by intrahepatic choleliths. Biopsy of the liver and gall bladder (GB) at the time of surgery showed a severe, subacute-to-chronic cholangiohepatitis with bile duct hyperplasia and periductal fibrosis and chronic neutrophilic cholecystitis. Bile culture was positive for Escherichia coli.
At a routine recheck, 83 days postoperatively, the cat was doing well clinically, and serum bilirubin and liver enzyme activity were normal. On ultrasound, the CBD remained tortuous but with reduced diameter (4.5 mm, previously 5.8 mm; normal <5 mm) 5 and contained anechoic bile and small choledocholiths. There was persistent intrahepatic bile duct distension. The cholecystoduodenostomy site was identified in the right cranial abdomen as a triangular viscus with a thick (3.2 mm; normal <1 mm), 6 hypoechoic wall and a broad-based attachment to the proximal descending duodenum (Figure 1). The GB contained a small amount of echogenic fluid and gas, associated with reverberation artefact. The adjacent duodenal wall was normal. The connection at the surgical site was approximately 11 mm in height. Similar to previous reports, suture material or fibrous scarring associated with suture material was seen at the junction of the GB and duodenum as tiny hyperechoic foci without artefact.7,8
Sonogram of the cholecystoduodenostomy site of case 1. The liver is seen cranially, to the left of the image (L). The gall bladder (large arrowheads) has a thickened wall and contains a mixture of echogenic fluid and gas. The attached duodenum (arrows) maintains normal wall layering. Suture/fibrous scar tissue (small arrowheads) is seen at the surgical site
About 1 year (383 days) postoperatively, the cat had an ultrasound evaluation for acute-on-chronic kidney disease. The surgery site was again identified. The GB contained a small amount of echogenic fluid and gas; its wall was moderately echogenic and remained thickened (2.5 mm). The CBD remained tortuous and relatively unchanged in size (4.8 mm) with echogenic fluid and choledocholiths. Intrahepatic bile duct distension was again seen. Total serum bilirubin and liver enzyme values were normal at this time.
The cat was euthanized 383 days after surgery for reasons unrelated to hepatobiliary disease. A necropsy was not performed.
Case 2
A 12-year-old spayed female domestic shorthair (DSH) cat was referred for surgical liver biopsies to investigate increased serum liver enzyme activity. Prior to referral, percutaneous ultrasound-guided liver biopsy was performed, but biopsy material was of poor diagnostic quality and surgical liver biopsies were recommended. There was no ultrasonographic evidence of EHBO at that time.
For unknown reasons, surgical biopsy was delayed for 4 months. At this time the cat was hyperbilirubinemic. An ultrasound examination was not performed. At exploratory laparotomy the CBD was dilated and the GB was non-expressible. A firm thickening occluded the CBD at the level of the duodenal papilla. A cholecystoduodenostomy was performed. Histopathologic evaluation of the liver biopsy showed vacuolar change, mild lymphoplasmacytic hepatitis, periportal hepatocellular necrosis, biliary hyperplasia, and sinusoidal and periductal fibrosis. Fine-needle aspiration of the lesion within the CBD showed a mildly atypical epithelial population, most consistent with hyperplasia; however, a well-differentiated neoplasm could not be ruled out.
Five days postoperatively the cat was presented for anorexia, vomiting and lethargy. Bloodwork at this time showed persistently elevated but improved hyperbilirubinemia and serum liver enzyme activity. On ultrasound, there was distension of the intrahepatic ducts, the cystic duct (4 mm) and the CBD (10.2 mm). The CBD contained echogenic fluid/material; its wall was echogenic and thickened. The cholecystoduodenostomy site was identified. The GB was collapsed, and its wall was thickened (3.6 mm) and echogenic. The connection of the surgical site was estimated to measure 14 mm. Suture material/fibrous scarring was seen. The adjacent duodenal wall was normal. The regional fat was slightly hyperechoic.
The cat remained intermittently inappetent with occasional vomiting and progressive weight loss. At 21 days after surgery, hyperbilirubinemia and elevated serum liver enzyme activity persisted but continued to improve. A recheck ultrasound showed slightly progressive CBD distension to a diameter of 12 mm. The surgery site was relatively unchanged and the regional fat was no longer hyperechoic. Intrahepatic bile duct distension persisted.
Given continued anorexia and repeated esophagostomy tube complications the patient was discharged with the plan to euthanize within a few days. The cat was lost to follow-up after 169 days following surgery.
Case 3
An 11-year-old spayed female DSH cat presented for progressively increased serum liver enzyme activity and hyperbilirubinemia. On abdominal ultrasound, EHBO was suspected secondary to a nodular thickening of the CBD near the duodenal papilla. Additional findings of GB wall thickening and a hypoechoic pancreas were suggestive of cholecystitis and pancreatitis.
At exploratory laparotomy the CBD was severely distended and tortuous with a firm thickening near the duodenal papilla. Although the duodenal papilla was patent, due to the thick nature of the bile and difficulty flushing the CBD, a cholecystoduodenostomy was performed. Hepatic biopsy specimens showed moderate-to-severe, chronic, lymphocytic cholangiohepatitis with vacuolar change, biliary hyperplasia, and portal and periductal fibrosis. The GB/CBD biopsy showed cystic mucosal hyperplasia.
In the first 3 days postoperatively, serum liver enzyme activity and hyperbilirubinemia improved, but on the fourth day, it abruptly worsened (from 9.4 mg/dl to 10.9 mg/dl; reference interval [RI] 0.1–0.3 mg/dl). The cat became febrile (103ºF [39.4ºC]; RI 99.5–102.5ºF [37.5–39.2ºC]). An abdominal ultrasound (day 5) showed that the CBD remained distended (13 mm, previously 12 mm) and tortuous, with anechoic contents and thickened, nodular walls. The cholecystoduodenostomy site was identified in the right cranial abdomen. The GB contained a small volume of anechoic fluid; its walls were echogenic and irregularly thickened (up to 4.5 mm). The duodenum maintained normal wall layering but was thickened (3.7 mm; RI 1.78–2.51 mm). 9 Suture material/fibrous scarring was seen. The regional fat was markedly hyperechoic and beam-attenuating. Persistent pancreatitis was suspected. There was moderate, slightly echogenic peritoneal effusion. An abdominocentesis was performed revealing a neutrophilic inflammation; a culture was not performed.
At recheck (day 11) the cat was lethargic, persistently inappetent and only tolerating small-volume feedings via the esophagostomy tube. Bloodwork showed progressive increases in serum liver enzyme activity and hyperbilirubinemia (19.3 mg/dl; RI 0.1–0.3 mg/dl). On abdominal ultrasound (14 days postoperatively), the cholecystoduodenostomy site was identified. The GB contained heterogeneously echogenic, multicystic, and irregularly marginated, vascular tissue. The CBD was progressively distended (16 mm) with echogenic contents. The adjacent duodenum maintained normal wall layering and was now reduced in thickness (2.6 mm). The connection at the surgical site was estimated to be 8 mm. Suture material/fibrous scarring was identified. Regional peripancreatic fat was slightly hyperechoic and hypoechoic nodules within it were concerning for carcinomatosis. Fine-needle aspiration of the tissue within the GB was consistent with mild inflammatory infiltration.
The cat was presented 6 days later for continued clinical deterioration. Bloodwork showed progressively increased serum liver enzyme activity and hyperbilirubinemia (20.2 mg/dl; RI 0.1–0.3 mg/dl). On abdominal ultrasound (22 days postoperatively), the previously described tissue within the GB filled its lumen and extended through the cholecystoduodenostomy site into the proximal duodenum, resulting in a mechanical ileus (Figure 2). It was difficult to delineate this tissue from wall of the GB, which was approximately 2.6 mm in thickness. The CBD was again filled with echogenic material and was mildly progressively distended (19 mm). Recurrent EHBO was also suspected. Nodules within regional fat were again seen, in addition to several serosal nodules, consistent with progressive carcinomatosis.
Sonogram of the cholecystoduodenostomy site in case 3. Cranial is to the left and caudal is to the right. A large, heterogeneous and multicystic mass fills and distends the gall bladder and cystic duct (long arrows). There is extension of the mass into the duodenum (asterisk), which resulted in a mechanical ileus in this patient. Suture/fibrous scar tissue (short arrow) is seen at the surgical site. Histopathology of the mass was consistent with extrahepatic cholangiocarcinoma
The owners elected humane euthanasia 22 days following surgery. A necropsy was not performed but a review of the original GB/CBD biopsy samples was consistent with extrahepatic cholangiocarcinoma.
Case 4
A 9-year-old spayed female Maine Coon cat was presented for a 2-day history of progressive lethargy and inappetence, elevated serum liver enzyme activity, hyperbilirubinemia and vomiting. On ultrasound examination, EHBO was suspected secondary to amorphous tissue focally obscuring the lumen of the dilated CBD.
At surgery, the GB and CBD were severely distended and diffuse thickening of the CBD wall was noted. A catheter could not be advanced into the GB. A cholecystoduodenostomy was performed. Histopathology of the biopsy from the distal CBD was initially reported as severe, chronic eosinophilic cholangitis. Hepatic biopsies were consistent with severe, diffuse, chronic lymphoplasmacytic and neutrophilic cholangiohepatitis with periductal fibrosis and bile duct ectasia. GB histopathology showed mild fibrosis and mucosal necrosis. Bile culture revealed a multidrug-resistant Enterococcus species.
On the fourth day postoperatively, the cat vomited multiple times and abdominal distension was noted. A repeat abdominal ultrasound revealed that intrahepatic bile duct distension seen preoperatively had resolved. The cholecystoduodenostomy site was identified in the cranial abdomen, to the right of midline. The GB had thick (2.8 mm), echogenic walls and was attached to the descending duodenum, just proximal to the duodenal papilla. The GB was moderately distended with echogenic fluid, as well as rounded (approximately 11 mm in diameter) echogenic tissue in the region of the GB neck extending into and distending the cystic duct. This tissue was initially suspected to represent hematoma or granulation tissue. Color flow Doppler evaluation was not performed. The surgical site connection was estimated to be up to 8 mm. Suture material/fibrous scarring was seen. Similar to the preoperative examination, the CBD had thickened, echogenic walls and a focal loss of visualization of the lumen. Evidence of gastric ileus and pancreatitis with regional steatitis were noted.
Follow-up ultrasound examinations were performed at 7, 10 and 17 days postoperatively to evaluate persistently decreased appetite and progressive worsening of biochemical changes. At each ultrasound examination, the intraluminal GB tissue progressed in size (from 22 mm in diameter to 29 mm) to eventually fill the GB, becoming a partly cavitated, moderately vascular, echogenic mass. Intrahepatic bile duct distension recurred. In the last two studies, the wall of the GB developed a layered appearance. Recurrent EHBO secondary to the mass within the GB was suspected and 19 days postoperatively an exploratory laparotomy and cholecystotomy was performed. At surgery, the CBD was described as stenotic and fibrotic. A vascular mass was removed from the GB. The cystic duct could not be catheterized, but the stoma of the cholecystoduodenostomy site was patent. Histopathology of the mass confirmed extrahepatic cholangiocarcinoma. Review of the initial surgical CBD biopsy was also consistent with cholangiocarcinoma.
The cat clinically declined 4 days following the second surgery owing to septic peritonitis and was euthanized (25 days following the initial surgery). A necropsy was not performed.
Case 5
A 10-year-old spayed female DSH cat was presented for further evaluation of progressive hyperbilirubinemia and elevated serum liver enzyme activity. Initial ultrasound showed hyperechoic hepatomegaly and a duplicated GB with two separate cystic ducts that converged on a single CBD. A pancreatic nodule was seen near the duodenal papilla. The cat was treated medically but, owing to continued inappetence, returned 4 days later. A percutaneous ultrasound-guided needle biopsy of the liver showed mild lymphoplasmacytic portal hepatitis and cholangitis with lipidosis and periductal fibrosis.
The cat remained lethargic and inappetent, with progressive hyperbilirubinemia. A recheck ultrasound was consistent with EHBO secondary to extension of the previously seen pancreatic nodule into the distal CBD.
A cholecystoduodenostomy was performed. During surgery, the pancreas was noted to be firm, enlarged and occluded the CBD. Pancreatic biopsies were initially interpreted as marked, diffuse, chronic, neutrophilic pancreatitis with atrophy and fibrosis. Hepatic histopathology showed moderate, chronic, neutrophilic cholangitis with bile duct dilation and periductal fibrosis.
The cat was discharged 9 days postoperatively. Hyperbilirubinemia improved; however, the cat remained lethargic and inappetent. A recheck ultrasound was performed 22 days postoperatively. Given that the GB was duplicated, the unmodified GB appeared to persist within the liver and was filled with echogenic debris; its walls were hypoechoic and thickened (1.3 mm). Immediately caudal to this, the surgical site was identified. The GB had heterogeneously hypoechoic and thickened walls (2.6 mm). The connection between the GB and duodenum was estimated to measure 4.5 mm. Suture material/scarring fibrosis was seen. The regional abdominal fat was hyperechoic. The cystic ducts and CBD remained tortuous with echogenic contents, but the CBD diameter had decreased from 14 mm to 8 mm. Gas was noted within the biliary tree and rerouted GB. The previously described pancreatic nodule was larger (19 mm; previously 11 mm) and had a hypoechoic to anechoic center; it obscured visualization of the duodenal papilla and deviated the course of the duodenum. The pancreaticoduodenal (PD) lymph node was hypoechoic but normal in size.
Over the next few weeks the cat showed progressive decline at home with worsening of liver enzyme activity and hyperbilirubinemia. On recheck ultrasound examination (39 days postoperatively), the hepatobiliary system and surgery site appeared unchanged. The pancreatic nodule (23 mm) and hypoechoic PD lymph node were larger (4.3 × 8 mm). The cat was euthanized owing to poor quality of life.
At necropsy, the pancreatic mass effaced a large portion of the pancreas and surrounded the CBD and pancreatic duct at the level of the duodenal papilla. Bile flow into the duodenum was obstructed at both the duodenal papilla and the surgical site. The GB contained purulent fluid. Histopathological evaluation of the pancreas confirmed pancreatic adenocarcinoma with intravascular, hepatic and splenic metastases. Review of the initial pancreatic biopsy was consistent with pancreatic adenocarcinoma.
Case 6
A 10-year-old female spayed Egyptian Mau cross cat was evaluated for hyporexia, vomiting and icterus. Bloodwork showed an inflammatory leukogram, hyperbilirubinemia and increased serum liver enzyme activity. Ultrasound findings were consistent with EHBO secondary to echogenic contents within the distal CBD. An exploratory laparotomy was performed. The GB and CBD were both subjectively severely distended and a focal (approximately 10 mm in length) thickening of the distal CBD was present immediately adjacent to the duodenal papilla. A choledochotomy was performed confirming a focally thickened wall, which was biopsied. Owing to concern for patency of the CBD, a cholecystoduodenostomy was performed. Surgical biopsies confirmed extrahepatic cholangiocarcinoma of the CBD, as well as mild, neutrophilic and lymphoplasmacytic hepatitis with mild lipidosis, biliary hyperplasia and periductal fibrosis. The cat was discharged after 5 days.
Thirteen days postoperatively, at routine recheck, the cat appeared nauseous and serum liver enzyme activity and hyperbilirubinemia persisted. On abdominal ultrasound, the cholecystoduodenostomy site was identified. The GB contained a small volume of echogenic fluid and gas. Its wall was hypoechoic, irregular and thickened (4 mm). The surgical connection was estimated to be 3.5 mm. Suture material/scarring fibrosis was seen. The abdominal fat in the region of the surgical site was mildly hyperechoic. The CBD remained distended (6.2 mm, previously 6.9 mm) with anechoic fluid and a thickened wall (2 mm). The previously described obstructive tissue/thickening was not seen. The adjacent duodenum appeared normal.
Chemotherapy was started 3 weeks postoperatively. The cat presented multiple times for re-evaluation over an approximately 2-year period and was reportedly doing well at home despite intermittent vomiting, lethargy and inappetence, supported by parenteral feeding via an esophagostomy tube. Hyperbilirubinemia was persistent but gradually improved (varying between 0.2–1 mg/dl; RI 0.1–0.3 mg/dl). Recheck ultrasound examinations were performed approximately every month for 5 months and then every 4–5 months afterwards.
On recheck ultrasound examinations, the cholecystoduodenostomy site was identified within the mid-to-right cranial abdomen. The wall of the GB was initially echogenic but subjectively decreased in echogenicity over time; it was asymmetrically thickened (3.8–6.7 mm) and variably collapsed or contained scant anechoic fluid and/or gas. The connection at the surgical site was estimated to measure up to 4.1 mm. Suture material/scarring fibrosis was seen. The regional abdominal fat normalized. Over serial examinations, the CBD was progressively distended (from 13 mm to 35 mm) and tortuous, with progressively organized echogenic contents and choleliths. Some similarly echogenic material was also seen within the intrahepatic biliary tree. An echogenic nodule within the distal CBD was monitored for change over time and grew from 6.6 mm in diameter to 8.2 mm. It never appeared obstructive as it never completely filled the lumen. Gas was intermittently noted throughout the biliary system. The duodenum adjacent to the surgery site remained within normal limits.
The cat presented for an episode of vomiting 415 days postoperatively. Serum liver enzyme activity and hyperbilirubinemia were relatively unchanged, but hepatomegaly was palpated. Fine-needle aspiration of the liver was suspicious for recurrent biliary carcinoma.
The patient developed hematemesis and anemia 816 days postoperatively. A definitive cause was not identified. Recurrent episodes of hematemesis and progressive anemia warranted hospitalization and multiple blood transfusions. Ultrasound of the hepatobiliary system and serum biochemical changes were otherwise relatively unchanged. Following presentation for another episode of severe anemia the cat was euthanized 1083 days following surgery.
A necropsy was performed revealing a new locally invasive pancreatic neuroendocrine tumor with metastases to the liver and GB. No evidence of biliary obstruction was described. Within the liver, there was diffuse fibrosis with biliary hyperplasia. Focally extensive cholangiectasia with intraluminal food material at the cholecystoduodenostomy site was also found.
Discussion
In this case series, six cats had a cholecystoduodenostomy performed to alleviate EHBO and had one or more postoperative ultrasound evaluations at different time points after surgery. The ultrasonographic features of the cholecystoduodenostomy sites are summarized in Table 3. The surgery site was identified in all six cats, most often within the right cranial abdomen. The GB had thick, most commonly echogenic walls (median 3.8 mm; range 2–6.7 mm). It was broadly attached to the descending duodenum, which maintained normal wall layering in all cats but was thickened in 4/6 (median 2.4 mm; range 1.5–3.7 mm).
Summary of salient ultrasonographic features of cholecystoduodenostomy sites
Number of ultrasound studies in which the surgical site was identified out of the total number of postoperative ultrasound examinations performed
Location in the abdomen was based on surrounding anatomy, but could not be confirmed due to the lack of an overhead video
GB = gall bladder
The GB was most often collapsed or contained a small amount of fluid. The connection between the GB and duodenum was difficult to evaluate given that the GB was often empty. This estimated measurement is therefore thought to be unreliable. Gas was intermittently noted within the biliary tree in 50% of the cats. This is most consistent with gastrointestinal reflux, which we suspect is due to the lack of a sphincter mechanism at the site of the rerouted GB. A correlation with progressive biochemical changes and/or worsening clinical signs was not identified. This finding was therefore not found to be a clear indicator of infection; however, the possibility of biliary infection secondary to reflux of gastrointestinal contents remains. 3
CBD distension was present in 5/6 cats on presurgical ultrasound examinations. In the only cat without distension preoperatively (case 2), the ultrasound was not performed immediately before surgery and the prior examination was several months prior to the onset of icterus. One of the four cats (case 3) with progressive CBD distension postoperatively was suspected to have recurrent EHBO. Another cat (case 4) with suspected recurrent EHBO had an unchanged CBD distension. Finally, one cat (case 5) with confirmed recurrent EHBO actually had improved CBD distension, despite gradual worsening of biochemical changes. Intrahepatic bile duct distension was noted prior to surgery in 2/6 cats. It resolved in one cat (case 4) following surgery but recurred with suspected recurrent EHBO. In the other cat (case 1), it persisted, unchanged, despite overall clinical improvement. Intrahepatic bile duct distension developed postoperatively in one cat (case 6), despite improved biochemical changes. Based on these findings, persistent biliary distension may be observed in cats following cholecystoduodenostomy and changes in biliary distension following surgery may not always correspond to biochemical changes or the presence of recurrent obstruction.
In two cats (cases 3 and 4), the rerouted GB became progressively distended with echogenic and vascular tissue, which led to a duodenal obstruction with suspected recurrent EHBO in case 3 and confirmed recurrent EHBO in case 4. In case 4, the echogenic tissue was initially mistaken for hematoma formation or granulation tissue. Color flow Doppler interrogation was performed on a later examination confirming moderate vascularity. Both cats were ultimately diagnosed with extrahepatic cholangiocarcinoma. Therefore, the presence of organized, echogenic material within the rerouted GB should be considered suspicious for neoplasia. Color flow Doppler can be useful to confirm vascularity of luminal contents.
Similar to human medicine, differentiation of inflammatory and neoplastic lesions of the bile ducts remains difficult owing to the fact that these tumors can be well differentiated and often accompanied by desmoplastic stroma and inflammation. 10 In cases 3, 4 and 5, initial biopsies of the GB/CBD, GB and pancreas, respectively, were described as inflammatory rather than neoplastic. On re-evaluation of the initial biopsies, with necropsy in one case (case 5), all three were diagnosed with malignant neoplasia (2/3 cholangiocarcinoma and 1/3 pancreatic adenocarcinoma). This further supports the difficulty of accurate histopathologic diagnosis, especially in regard to well-differentiated neoplasms.
Consistent with previous studies, there were high postoperative morbidity and mortality rates within this study population.1,2,4 The longest survival time following surgery was for case 6, which is subjectively considered an outlier given that the patient was maintained by esophagostomy tube feedings with questionable clinical improvement. Case 6 excluded, only 1/6 patients (case 1) had a cause of death that was considered completely unrelated to the previous episode of EHBO. Survival time in this patient was 383 days. This is in line with the previous conclusion that biliary obstruction secondary to cholelithiasis carries a better prognosis than obstruction owing to either inflammation or neoplasia. 2 The remainder of the patients were ultimately euthanized due to either a lack of clinical improvement (case 2), progression of neoplasia with or without recurrent obstruction (cases 3 and 5) or dehiscence/leakage from the surgical site (case 4).
Conclusions
The cholecystoduodenostomy site was visualized in all cats as a thick-walled GB, which was either empty or contained scant fluid/gas and was broadly attached to the descending duodenum. CBD distension persisted in all cases after surgery, often similar to the preoperative appearance. Changes to intrahepatic bile duct distension were variable. Postoperative changes in biliary distension did not consistently correlate to the clinical presentation, emphasizing the need for evaluation in the light of biochemical parameters. Finally, the development of echogenic tissue within the biliary tree may represent neoplasia in spite of initial histopathologic results of inflammation.
Footnotes
Acknowledgements
The authors thank the Pathology Department at the Cummings School of Veterinary Medicine at Tufts University, especially Cesar Piedra-Mora DVM; Kara Priest DVM, MS, DACVP; and Francisco O Conrado DVM, MSc, DACVP.
Conflict of interest
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Ethical approval
This work involved the use of non-experimental animals only (including owned or unowned animals and data from prospective or retrospective studies). Established internationally recognised high standards (‘best practice’) of individual veterinary clinical patient care were followed. Ethical approval from a committee was therefore not necessarily required.
Informed consent
Informed consent (either verbal or written) was obtained from the owner or legal custodian of all animal(s) described in this work (either experimental or non-experimental animals) for the procedure(s) undertaken (either prospective or retrospective studies). No animals or humans are identifiable within this publication, and therefore additional informed consent for publication was not required.
