Background and aims: The defining of the autoimmune hepatitis (AIH) and primary biliary cirrhosis (PBC) overlap syndrome as a separate clinicopathological entity has been controversial and temporally and geographically subjective.
Methods: From 1979 until 2000, 227 patients diagnosed with AIH, PBC or the overlap thereof were treated. Cases with genuine AIH/PBC overlap syndrome were sorted out using close clinical follow up and serial liver biopsies.
Results: Of the 227 patients, 19 (8.4%) were diagnosed with the AIH/PBC overlap syndrome. They all cleared a score >10 for the diagnosis of AIH, and tested positive for antimitochondrial antibodies during their courses. Long-term follow up with frequent histological examinations, however, established the diagnosis of AIH/PBC overlap syndrome in only two (0.8%) patients. The most powerful factor distinguishing AIH from PBC was acidophilic bodies in lobules that were detected significantly more frequently in patients with AIH than PBC or spurious overlap syndrome (39/46 [85%]vs 3/85 [4%], P < 0.001). It was more reliable than bile-duct lesions for the distinction of PBC from AIH.
Conclusions: Although AIH/PBC overlap syndrome does exist, it is infrequent and needs to be diagnosed carefully using close clinical and histological follow up to enable timely and effective treatment.