Arterialization and Ductular Metaplasia of Centrizonal Scars in Chronic Venous Outflow Obstruction: A Frequently Misinterpreted Lesion
Bilge Can, Gregor Krings, Linda Ferrell. 19 Mayis Univ, Samsun, Turkey; Univ Calif, San Francisco
Background: Chronic venous outflow obstruction (CVOO) is characterized by centrizonal hepatocyte ischemia with hepatocyte atrophy, necrosis, sinusoidal fibrosis and zone 3 scarring. Recent studies have shown that other conditions associated with centrizonal scarring, including steatohepatitis and alcoholic cirrhosis, often show architectural remodeling resulting in aberrant centrizonal arterialization and ductular metaplasia (DM) of hepatocytes. In our experience, centrizonal scars in CVOO may also develop arterial ingrowth and DM, but this has not been systematically evaluated. Recognition of these changes is essential to prevent misinterpretation of centrizonal lesions as portal tracts and misdiagnosis of CVOO as a biliary tract problem and/or ductopenia.
Design: Fifty-eight cases of documented CVOO were evaluated for centrizonal arteries and microvessels, DM, and fibrosis. The number of centrizonal arteries in scar was graded as 0-3 by H&E and trichrome stains. DM was semi-quantitatively scored on a scale of 0-3. Immunostains for keratin 7 (K7) and CD34 were performed (n=24) to assess for DM and hepatocyte staining as well as centrizonal arteries and microvessels, respectively. Centrizonal fibrosis was staged using the NASH CRN system. Patients with other concomitant conditions or cholestatic liver injury were excluded.
Results: Arterial ingrowth was identified in centrizonal scars in 47 (81%) of 58 cases. Arteries were common (grade 2-3) in 27/58 (46.6%). CD34+ microvessels were observed in centrizonal scars in 22 (91.7%) of 24 cases. Centrizonal DM was identified in 41 (70.7%) of 58 cases by H&E. K7 staining revealed centrizonal DM and hepatocyte intermediate staining in 20 (83.3%) and 22 (91.7%) of 24 cases, respectively. Centrizonal arteries and DM were significantly more frequent in cases with higher stage fibrosis (p=0.008 and p=0.001, respectively). Significant association was found between the presence of centrizonal arterialization and DM (p=0.01).
Conclusions: Centrizonal arterialization and DM are commonly associated with CVOO, and both correlate with the stage of fibrosis. Arterial ingrowth appears to be part of the vascular remodeling of progressive fibrosis. DM and intermediate K7 staining of hepatocytes are likely due to ischemia of hepatocytes in Zone 3 in CVOO. Recognition of these aberrant features is critical to prevent misinterpretation of central zones as portal tracts, which may otherwise result in misdiagnosis of CVOO as a biliary tract problem with or without ductopenia.
Wednesday, March 21, 2012 9:30 AM
Poster Session V # 243, Wednesday Morning