Sclerosing cholangitis (SC) is a heterogeneous disease entity. Different etiologies such as choledocholithiasis, biliary tumor, or pericholangitis can manifest as SC. Hepatic inflammatory pseudotumor (IP) is rarely associated with SC (sclerosing cholangitis associated with hepatic inflammatory pseudotumor; SC-hepatic IP), but sclerosing pancreatitis (SP) is not infrequently associated with bile duct lesions (sclerosing pancreatitis-associated sclerosing cholangitis; SP-SC). In this study, we compared the histologic changes of hepatic hilar and extrahepatic bile duct lesions of SC (7 cases), SC-hepatic IP (5 cases), SP-SC (5 cases), and typical primary sclerosing cholangitis (PSC) (5 cases). Histologically, all SP-SC cases showed extensive and dense fibrosis with marked lymphoplasmacytic infiltration, many eosinophils, and obliterative phlebitis. Four cases of SC showed bile duct lesions similar to those of SP-SC, whereas other three cases of SC showed milder lymphoplasmacytic infiltration, scant eosinophilic cell infiltration, and no obliterative phlebitis. All SC-hepatic IP cases showed bile duct lesions identical to those of SP-SC. Immunohistochemically, many IgG4-positive plasma cells were found in the bile duct lesions of all SP-SC cases, 4 SC cases with marked lymphoplasmacytic infiltration, and all SC-hepatic IP cases. By contrast, IgG4-positive plasma cells were scarce or hardly found in the remaining 3 SC cases and all PSC cases. In conclusion, 4 SC cases and all SC-hepatic IP cases showed bile duct lesions identical to those of SP-SC, suggesting that these three conditions may be a single disease entity. Their pathogenesis may be similar or closely related to that of SP, and in that respect they may represent an IgG4-related biliary disease. They may respond to steroid therapy as SP does.

Chronic sclerosing sialadenitis (CSS) is a cryptogenic tumor-like condition of the salivary gland(s). While immune-mediated processes are suspected in its pathogenesis, and CSS is occasionally reported to be associated with sclerosing pancreatitis, an IgG4-related disease, the exact immunopathologic processes of CSS remain speculative. In this study, we examined the clinicopathologic findings of CSS (12 cases) in comparison with sialolithiasis (8 cases) and Sjogren's syndrome (13 cases), and tried to clarify whether CSS is an IgG4-related disease or not. Submandibular gland(s) were affected in all cases of CSS. CSS cases could be divided into two types: 5 cases were associated with sclerosing lesions in extrasalivary glandular tissue (systemic type), while only salivary gland(s) were affected in the remaining 7 cases (localized type). In the former type, which showed male predominance, bilateral salivary glands were frequently affected, and eosinophilia and elevations of gamma-globulin and IgG in serum were frequently found. Histologically, all cases of CSS showed marked lymphoplasmacytic infiltration admixed with fibrosis and the destruction of glandular lobules. Obliterative phlebitis was found in the affected salivary glands in all cases of CSS. Immunohistochemically, the proportion of IgG4/IgG-positive plasma cells was more than 45% in CSS, while it was less than 5% in controls. The resemblance of the clinicopathologic features of CSS with those of sclerosing pancreatitis suggests the participation of a similar immunopathologic process with IgG4 disturbance in CSS. The abundance of IgG4-positive plasma cells in the lesions would be useful for distinguishing CSS from other forms of sialadenitis.

Recently the authors proposed a new staging and grading system for primary biliary cirrhosis (PBC) that takes into account necroinflammatory activity and histological heterogeneity. Herein is proposed a convenient version of this system. Scores for fibrosis, bile duct loss, and chronic cholestasis were combined for staging: stage 1, total score of 0; stage 2, score 1-3; stage 3, score 4-6; and stage 4, score 7-9. Cholangitis activity (CA) and hepatitis activity (HA) were graded as CA0-3, and HA0-3, respectively. Analysis of interobserver agreement was then conducted. Digital images of 62 needle liver biopsy specimens of PBC were recorded as virtual slides on DVDs that were sent to 28 pathologists, including five located overseas. All participants were able to apply this version in all 62 cases. For staging, kappa was 0.385 (fair agreement) and the concordance rate was 63.9%. For necroinflammatory activity, the kappa and concordance rate were 0.110 (slight agreement) and 36.9% for CA, and 0.197 (slight agreement) and 47% for HA, respectively. In conclusion, this new staging and grading system for PBC seems to be more convenient and practical than those used at present, but more instruction and guidance are recommended for the grading of necroinflammatory activity in practice.

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Biliary lining epithelia of the bile ducts in biliary diseases are known to have intraepithelial atypical/proliferative lesions related to the development of cholangiocarcinoma. The purpose of the present study was to determine the histological criteria for these lesions based on interobserver agreement. Digital images of 30 intraepithelial atypical/proliferative lesions in the stone-containing intrahepatic bile ducts of hepatolithiasis (30 cases) were sent to 10 pathologists. At first, 10 pathologists made a diagnosis (either of reactive/regenerative change, low-grade or high-grade biliary intraepithelial neoplasia (BilIN-1 and BilIN-2), or in situ carcinoma (BilIN-3)) based on their own criteria. The histological criteria for these four lesions were then determined, and the digital images of the same lesions with proposed criteria were re-distributed. Interobserver agreement on these four lesions was slightly improved (kappa = 0.44, first diagnosis; 0.49, second diagnosis) and intraobserver agreement was 'almost perfect' (kappa = 0.82 at both first and second diagnosis). Interobserver agreement between BilIN-1 and BilIN-2 and that between BilIN-2 and BilIN-3 were 'moderate', although the agreement between regenerative/reactive change and BilIN-1 was 'fair'. In this report, we propose histological criteria for reactive/regenerative change, BilIN-1, BilIN-2 and BilIN-3. Improvement of interobserver agreement suggests their applicability in diagnostic and research fields.