[Congenital bile duct cysts and liver fibrosis in a foal].

This research study reports on a case of a three-week-old foal that was brought to the clinic due to a minor injury but eventually diagnosed with congenital polycystic liver disease, fibrosis, and cholangitis. The disease was characterized by fluid-filled cystic structures in the liver, enlargement of the liver, and increasing inflammation of the bile ducts.

Clinical Presentation

• The foal was initially admitted to the clinic due to a small injury on its lower jaw. However, the animal was also showing other symptoms such as diarrhea, a noticeably distended abdomen, and a general deterioration in its condition which did not seem to relate to the injury.

Diagnosis

• The diagnosis began with an abdominal radiography that revealed reduced details and an abnormal displacement of the intestine to the dorsocaudal region.
• Further examination using ultrasound revealed multiple fluid-filled cystic structures, several centimeters in diameter. These structures were determined to be associated with the liver.

Surgery and Necropsy

• During a surgical intervention and subsequent necropsy, the liver was discovered to be significantly enlarged and firm, characterized by large, thin-walled cysts filled with bile-like fluid, ranging from 4 to 20 centimeters in diameter.

Pathologic Findings

• Pathologic assessment showcased certain significant attributes. There was a noted proliferation of small bile ducts and interlobular connective tissue. Additionally, they detected focal subacute cholangitis, which is an inflammation of the bile ducts.

Final Diagnosis

• The overlying condition of the foal, based on the gross and histological findings, was congenital polycystic liver disease accompanied by liver fibrosis and an ascending cholangitis. This disease is characterized by the growth of numerous cysts in the liver and expansion of the connective tissue between the liver lobules. It is suspected to have been present in the foal from birth.