Primary Biliary Cholangitis (PBC): This is the most likely diagnosis given the question's context. PBC is a chronic liver disease characterized by the progressive destruction of the bile ducts within the liver, leading to cholestasis and, ultimately, liver cirrhosis. The diagnosis is often suggested by elevated alkaline phosphatase levels, positive antimitochondrial antibodies (AMAs), and histological findings on liver biopsy.

Primary Sclerosing Cholangitis (PSC): This condition involves inflammation and scarring of the bile ducts, which can lead to narrowing and obstruction. While it shares some similarities with PBC, PSC tends to affect both intrahepatic and extrahepatic bile ducts and is more commonly associated with inflammatory bowel disease.
Autoimmune Hepatitis (AIH): AIH is a disease in which the body's immune system attacks liver cells. It can present with a wide range of symptoms and liver function test abnormalities, including elevated liver enzymes and positive autoantibodies.
Drug-Induced Cholestasis: Certain medications can cause cholestasis, mimicking the presentation of PBC. A thorough medication history is essential to consider this diagnosis.

Hepatocellular Carcinoma: Although less likely, missing a diagnosis of hepatocellular carcinoma (liver cancer) could be devastating. Risk factors include cirrhosis, which can be a late complication of untreated PBC.
Wilson's Disease: This genetic disorder leads to copper accumulation in the liver and can cause liver disease, neurological symptoms, and psychiatric problems. It's crucial to diagnose early, as treatment can prevent progression.
Budd-Chiari Syndrome: This condition, caused by thrombosis of the hepatic veins, can present with acute liver dysfunction and should be considered in cases of rapid deterioration.

Sarcoidosis: A systemic granulomatous disease that can affect the liver, causing cholestasis or hepatitis. It's less common but should be considered in the differential diagnosis, especially if other systemic symptoms are present.
Lymphoma: Certain types of lymphoma can involve the liver and cause cholestasis. This diagnosis is rare but important to consider, especially in patients with systemic symptoms or known lymphoma.
Idiopathic Adult Ductopenia: A rare condition characterized by the loss of intrahepatic bile ducts, which can lead to cholestasis. It's a diagnosis of exclusion and should be considered when other causes of cholestasis have been ruled out.