Ultrasonographic and clinicopathologic features of segmental dilatations of the common bile duct in four cats

Surgical approach to a biliary tract cyst in an elderly cat

Choledochal cyst or biliary tract cyst is a pathological condition characterized by abnormal dilation of the hepatobiliary system. In veterinary medicine, case descriptions and histological characterizations of this biliary malformation are scarce, requiring reliance on data from human medicine. A presumptive diagnosis typically involves imaging studies, with histopathological examination required for confirmation. Treatment often involves surgical intervention to remove the cyst and restore normal biliary function. A 15-year-old mixed-breed domestic female cat presented with vomiting and anorexia. Ultrasonographic examination revealed a dilation adjacent to the caudal aspect of the gallbladder. The patient underwent surgical intervention, during which a sacculation in the cystic duct region was identified and completely excised. Histopathological analysis confirmed the diagnostic suspicion of a biliary tract cyst. Despite the limited veterinary literature, the success of the surgical intervention, involving complete cyst removal, was evident. The patient remains stable and fully recovered twelve months post-surgery.

Computed tomographic features of exocrine pancreatic carcinomas in dogs and cats

Exocrine pancreatic carcinomas are uncommon in dogs and cats, and diagnosis with diagnostic imaging can be challenging. This retrospective, multi-institutional, descriptive study was performed to evaluate the CT features of exocrine pancreatic carcinomas. The CT examinations of 18 dogs and 12 cats with exocrine pancreatic carcinomas diagnosed by cytology or histopathology were reviewed. The CT features of exocrine pancreatic carcinomas included a well-defined mass in 28/30 (93%) with contrast enhancement in 27/30 (90%), commonly heterogeneous 22/30 (73%); often with a nonenhancing fluid to soft tissue attenuating center 12/30 (40%). The right lobe of the pancreas was the most common location, 14/30 (47%), then the left lobe, 10/30 (33%), and the body, 6/30 (20%). Extrahepatic biliary duct dilation was present in six animals; 5/6 (83%) of the masses were located in the right pancreatic lobe. Additional findings included peripancreatic fat-stranding 17/30 (57%), lymphadenopathy 16/30 (57%), peripancreatic soft tissue nodules 12/30 (40%), and free fluid 10/30 (33%). When comparing the imaging features of dogs and cats, there was a large overlap in imaging characteristics. There was a significant difference between the height of the masses, with dogs having larger masses (P-value.0028). Lymphadenopathy was more likely in larger masses [increased height (P-value.029)]. Cats were significantly older than dogs (P-value.0355). Pancreatic carcinomas were commonly identified as masses with heterogeneous contrast enhancement and a nonenhancing fluid to soft tissue attenuating center with concurrent peripancreatic changes (fat-stranding and/or soft tissue nodules) and lymphadenopathy.

Surgical Management Of Feline Biliary Tract Disease: Decision-making and techniques

PRACTICAL RELEVANCE

Diseases of the hepatobiliary system are not uncommon in first-opinion practice. The anatomy of the feline hepatobiliary tract differs from that of dogs and may predispose cats to inflammatory hepatobiliary disease. Case management can be challenging, and the prognosis is variable and dependent on the underlying disease process.

CLINICAL CHALLENGES

Biliary tract disease in the cat has non-specific clinical signs that overlap with those of diseases of other body systems. Diagnostic tests of the hepatobiliary system are widely available, but interpretation of results can be challenging. Deciding on medical or surgical management can also be challenging; for example, various degrees of cholestasis may be seen with different diseases and disease severities, and will influence the decision to manage the patient medically or surgically. Surgery is indicated in cases of bile peritonitis, severe cholestasis, focal neoplasia or disease that is refractory to medical management. Intensive perioperative and postoperative management, with 24 h hospitalisation facilities, is essential.

AUDIENCE

This review article is written for the small animal general/primary care practitioner, with an emphasis on decision-making in the surgical management of feline hepatobiliary disease.

EVIDENCE BASE

Evidence available in the published literature is reviewed and presented, and the inherent limitations are discussed.

Feline Cyst-like Lymphocytic Cholangiohepatitis in a Cat: First Case Report

A 5-year-old female neutered domestic short-haired cat presented with abdominal enlargement. An abdominal ultrasound revealed that large multiple hepatic cysts with irregular walls, hypoechoic fluid, and internal septations occupied most of the liver parenchyma. Serum liver enzymes, bilirubin, and bile acids concentrations were within normal limits. A fecal examination using simple floatation and formalin-ether sedimentation techniques was negative for liver fluke (Platynosomum fastosum), intestinal protozoa, and other helminth eggs. Praziquantel was prescribed for two distinct courses one month apart without obvious improvement of the hepatic cysts. An abdominal laparotomy and histopathological examination finally enabled diagnosis of cyst-like lymphocytic cholangiohepatitis of the liver tissue. Twelve weeks of oral prednisolone resulted in marked ultrasonographic improvement of the hepatic cysts. The liver parenchyma was heterogeneous and filled with multiple small anechoic cavities. Twenty-three months after ceasing the prednisolone, there was no recurrence of hepatic cysts.

Challenging diagnostic work-up of a massive fluid-filled structure in the cranial abdomen of a cat

A 9-year-old female, neutered European shorthair cat was presented with acute vomiting, obvious jaundice and painful enlargement of the abdomen. Icteric skin and mucous membranes in addition to severe bilirubinaemia (mainly direct bilirubin) and a large increase in liver enzyme activities were the main findings at the initial examination. Radio- and ultrasonographic evaluation revealed a massive fluid-filled structure caudal to the liver displacing abdominal organs, in particular the stomach. As this structure with a diameter of 8-10 cm occupied considerable space in the cranioventral abdomen, a detailed ultrasonographic examination of the liver and the gallbladder, and determination of the structure's association with a particular abdominal organ was initially impossible. Via ultrasound-assisted puncture under general anaesthesia 300 ml of an almost clear fluid could be aspirated. Cytological examination revealed a cyst content-like fluid with cell detritus.Further ultrasonographic and computed tomographic diagnostics followed by abdominal laparotomy finally enabled diagnosis of a cystic dilatation of the entire common bile duct and accumulation of white bile. Histopathological examination after euthanasia (requested by the owner) identified lymphoplasmacytic cholangitis and necrosis of the duodenal papilla. The massive dilatation of the common bile duct complicated its definite diagnosis by diagnostic imaging methods. It was most likely caused by a longer-standing obstruction of the bile flow by lymphoplasmacytic cholangitis with necrosis and granulation tissue formation in the area of the duodenal papilla. An interesting but initially misleading feature was the presence of white bile. The etiology of this extremely rare condition remains obscure but in the described case a manifestation of impaired hepatocyte function secondary to biliary stasis is suspected to be the cause.

Pancreatic enzyme activity in the bile of healthy cats and its association with biliary morphology

Background

In human medicine, congenital maljunction of the common bile duct (CBD) and main pancreatic duct (MPD), or pancreatobiliary maljunction (PBM), is a known cause of cholecystitis.

Objective

Pancreatic enzyme activity in the bile (a diagnostic marker for PBM) of healthy cats was measured to determine normal values and evaluate its relationship with biliary morphology.

Animals

Fifty‐two healthy cats.

Methods

Cross‐sectional study of the biliary tracts of healthy cats during laparoscopic ovariohysterectomy and measurement of pancreatic enzyme activity in bile. The cats were divided into groups A and B based on the ratio of the diameter of the cystic duct (CD) to the CBD. The normal ratio was 3.4. Pancreatic enzyme activity in bile was compared between the groups.

Results

The CBDs were straight in all cases, whereas the CDs were variably tortuous or dilated. Amylase activity in the bile (median, <100 U/L; range, <100‐591 U/L) was lower than in serum in all cases, and group B, which had a CD/CBD ratio >3.4, had significantly higher amylase activity (median, 109 U/L; range, <100‐591 U/L) in the bile than did group A (median, <100 U/L; range, <100‐238 U/L), which had a CD/CBD ratio <3.4 (P = .0009).

Conclusions and Clinical Importance

The results suggest that a dilated CD is associated with reflux of pancreatic juice. In the future, it will be necessary to examine the clinical usefulness of these findings by measuring pancreatic enzyme activity in the bile of cats with cholangitis.

Choledochal cyst with secondary cholangitis, choledochitis, duodenal papillitis, and pancreatitis in a young domestic shorthair cat

Choledochal cysts, congenital segmental dilations of the common bile duct, have been reported in few cats, and histologic characterization is lacking. A 20-mo-old spayed female domestic shorthair cat was presented because of vomiting and weight loss. There was progressive elevation of liver enzyme activity (ALT > ALP, GGT) and hyperbilirubinemia. Diagnostic imaging identified focal cystic dilation of the common bile duct, dilation and tortuosity of adjacent hepatic ducts, and a prominent duodenal papilla. A choledochal cyst was suspected, and the animal was euthanized. On postmortem examination, there was a 2-cm, firm, thickened, cystic dilation of the common bile duct, patent with adjacent ducts. Histologically, the cyst wall was expanded by fibroblasts, collagen, and lymphoplasmacytic inflammation. Adjacent bile ducts were markedly dilated and tortuous, with lymphoplasmacytic inflammation and papillary mucosal hyperplasia that extended to the major duodenal papilla. There was chronic neutrophilic cholangitis, suggesting bacterial infection and/or disturbed bile drainage, extrahepatic obstruction, and lymphoplasmacytic pancreatitis with ductular metaplasia. Prominent lymphoid follicles within biliary ducts and duodenum suggested chronic antigenic stimulation. Choledochal cysts can be associated with chronic neutrophilic cholangitis, extrahepatic obstruction, choledochitis, duodenal papillitis, and pancreatitis, and should be a differential for increased hepatic enzymes and hyperbilirubinemia in young cats.

Feline abdominal ultrasonography: what's normal? what's abnormal? The biliary tree

PRACTICAL RELEVANCE

Abdominal ultrasound plays a vital role in the diagnostic work-up of many cats presenting to general and specialist practitioners. The biliary tree encompasses the liver, gall bladder and bile ducts, although only diseases affecting the latter two are discussed here. Diseases of the bile ducts and gall bladder are more common than those of the liver parenchyma and ultrasound plays an important role in their diagnosis.

CLINICAL CHALLENGES

Despite ultrasonography being a commonly used modality, many practitioners are not comfortable performing an ultrasound examination or interpreting the resulting images. Even differentiating between normal variation and pathological changes can be challenging for all but the most experienced. In addition, a lack of pathological change does not necessarily rule out disease; for example, absence of gall bladder and/or extrahepatic biliary distension is not sufficient to exclude the possibility of biliary obstruction, and in many cases of cholangitis the liver and biliary tree are unremarkable on ultrasound examination.

EQUIPMENT

Ultrasound facilities are readily available to most practitioners, although use of ultrasonography as a diagnostic tool is highly dependent on operator experience.

AIM

This review, part of an occasional series on feline abdominal ultrasonography, discusses the appearance of the normal and diseased biliary system. It is aimed at general practitioners who wish to improve their knowledge and confidence in feline abdominal ultrasound and is accompanied by high-resolution images. Percutaneous ultrasound-guided cholecystocentesis is also covered. Ultrasound examination of the liver was discussed in an article published in January 2019 and an upcoming article will cover hepatic vascular anomalies.

EVIDENCE BASE

Information provided in this article is drawn from the published literature and the author's own clinical experience.