The Autoimmune Gender Gap: A Rare Case of a Male Patient With Overlapping Autoimmune Hepatitis and Primary Biliary Cholangitis.

Autoimmune hepatitis (AIH) is a condition resulting in chronic, inflammatory changes to the liver. Primary biliary cholangitis (PBC) is an autoimmune condition that destroys intrahepatic bile ducts. Overlap syndrome with concomitant AIH and PBC comprises a rare subgroup of patients with immune-mediated liver disease, with incidence rates of male patients being exceedingly uncommon in a predominantly female patient population. Our case report investigates a rare case of a 41-year-old male patient diagnosed with overlapping AIH and PBC. He initially presented with symptoms of fatigue, pruritus, and episodes of Raynaud's phenomenon, in addition to findings of persistently elevated liver enzymes despite lifestyle modifications. He had no past medical history, no history of alcohol use disorder, and no family medical history of chronic liver disease. Imaging did not reveal evidence of cirrhosis. Further diagnostic workup was significant for elevated immunologic markers for antinuclear antibodies (ANA) with positive centromere and cytoplasmic patterns, antimitochondrial antibodies (AMA) with F-actin antibodies, anti-smooth muscle antibodies (ASMA), and cytoplasmic antinuclear cytoplasmic antibodies (ANCA C). Liver biopsy showed prominent plasma cells and rare granulomas, consistent with the diagnosis of AIH with a component of PBC, respectively. He was started on ursodeoxycholic acid (UDCA), demonstrating a near-complete clinical response with resolution of symptoms and normalization of liver enzymes. Studies investigating the low incidence of male patients with overlap syndrome are limited, as current research is overwhelmingly based on studies with predominantly female subjects. However, most studies generally recommend treatment with both UDCA and corticosteroids to reduce symptoms and biochemical markers. Our case report highlights a rare case of a male patient documenting excellent biochemical and clinical responses to monotherapy with UDCA. A possible theory is that our patient's early treatment (prior to advanced disease progression) is associated with his near-complete biochemical response and symptomatic resolution on UDCA alone. Further research is needed to fully understand the clinical course and long-term prognosis of male patients with overlap syndrome. Our patient remains in life-long follow-up to monitor if or when he requires treatment with corticosteroids in addition to current monotherapy with UDCA.​.