Kenji Notohara

Consensus statement on the pathology of IgG4-related disease.

IgG4-related disease is a newly recognized fibro-inflammatory condition characterized by several features: a tendency to form tumefactive lesions in multiple sites; a characteristic histopathological appearance; and—often but not always—elevated serum IgG4 concentrations. An international symposium on IgG4-related disease was held in Boston, MA, on 4–7 October 2011. The organizing committee comprising 35 IgG4-related disease experts from Japan, Korea, Hong Kong, the United Kingdom, Germany, Italy, Holland, Canada, and the United States, including the clinicians, pathologists, radiologists, and basic scientists. This group represents broad subspecialty expertise in pathology, rheumatology, gastroenterology, allergy, immunology, nephrology, pulmonary medicine, oncology, ophthalmology, and surgery. The histopathology of IgG4-related disease was a specific focus of the international symposium. The primary purpose of this statement is to provide practicing pathologists with a set of guidelines for the diagnosis of IgG4-related disease. The diagnosis of IgG4-related disease rests on the combined presence of the characteristic histopathological appearance and increased numbers of IgG4+ plasma cells. The critical histopathological features are a dense lymphoplasmacytic infiltrate, a storiform pattern of fibrosis, and obliterative phlebitis. We propose a terminology scheme for the diagnosis of IgG4-related disease that is based primarily on the morphological appearance on biopsy. Tissue IgG4 counts and IgG4:IgG ratios are secondary in importance. The guidelines proposed in this statement do not supplant careful clinicopathological correlation and sound clinical judgment. As the spectrum of this disease continues to expand, we advocate the use of strict criteria for accepting newly proposed entities or sites as components of the IgG4-related disease spectrum.

International Consensus Diagnostic Criteria for Autoimmune Pancreatitis: Guidelines of the International Association of Pancreatology

Objectives: To achieve the goal of developing international consensus diagnostic criteria (ICDC) for autoimmune pancreatitis (AIP). Methods: An international panel of experts met during the 14th Congress of the International Association of Pancreatology held in Fukuoka, Japan, from July 11 through 13, 2010. The proposed criteria represent a consensus opinion of the working group. Results: Autoimmune pancreatitis was classified into types 1 and 2. The ICDC used 5 cardinal features of AIP, namely, imaging of pancreatic parenchyma and duct, serology, other organ involvement, pancreatic histology, and an optional criterion of response to steroid therapy. Each feature was categorized as level 1 and 2 findings depending on the diagnostic reliability. The diagnosis of type 1 and type 2 AIP can be definitive or probable, and in some cases, the distinction between the subtypes may not be possible (AIP-not otherwise specified). Conclusions: The ICDC for AIP were developed based on the agreement of an international panel of experts in the hope that they will promote worldwide recognition of AIP. The categorization of AIP into types 1 and 2 should be helpful for further clarification of the clinical features, pathogenesis, and natural history of these diseases.

Recommendations for the nomenclature of IgG4-related disease and its individual organ system manifestations

John H. Stone, Arezou Khosroshahi, Vikram Deshpande, John K. C. Chan, J. Godfrey Heathcote, Rob Aalberse, Atsushi Azumi, Donald B. Bloch, William R. Brugge, Mollie N. Carruthers, Wah Cheuk, Lynn Cornell, Carlos Fernandez-Del Castillo, Judith A. Ferry, David Forcione, Gunter Kloppel, Daniel L. Hamilos, Terumi Kamisawa, Satomi Kasashima, Shigeyuki Kawa, Mitsuhiro Kawano, Yasufumi Masaki, Kenji Notohara, Kazuichi Okazaki, Ji Kon Ryu, Takako Saeki, Dushyant Sahani, Yasuharu Sato, Thomas Smyrk, James R. Stone, Masayuki Takahira, Hisanori Umehara, George Webster, Motohisa Yamamoto, Eunhee Yi, Tadashi Yoshino, Giuseppe Zamboni, Yoh Zen, and Suresh Chari

Solid-pseudopapillary tumor of the pancreas: immunohistochemical localization of neuroendocrine markers and CD10.

To clarify the neuroendocrine differentiation and CD10 expression in solid-pseudopapillary tumors (SPTs) of the pancreas, we performed immunohistochemical analysis in 19 such tumors, including one solid-pseudopapillary carcinoma (SPC), along with 20 pancreatic neuroendocrine tumors (PNTs), six acinar cell carcinomas (ACCs), and one pancreatoblastoma (PB). We used antisera directed against CD56, synaptophysin, protein gene product 9.5, the alpha-subunit of Go protein, chromogranin A, CD10, trypsin, chymotrypsin, various cytokeratins (CKs), CA19-9, vimentin, and alpha-1-antitrypsin (AAT). All SPTs exhibited immunoreactivity for CD56 and CD10, and 15 expressed other neuroendocrine markers focally with the exception of chromogranin A. Frequent clustering of synaptophysin-positive cells was noted. Two cases contained a peculiar nodule that cytomorphologically and immunohistochemically resembled PNT. CD10-positive cells were scarce in one SPC. PNTs were CD56-positive, but often with faint intensity, and staining for other neuroendocrine markers, including chromogranin A, was diffusely positive. CD10 was detected, mostly in a focal pattern, in five PNTs. Pan-CK, CK8, CK18, and CK19 were more frequently demonstrated in PNT than SPT. Vimentin and AAT were often identified in PNT as well and were not specific for SPT. ACCs were CD56-negative, with the exception of one case designated as a mixed acinar-endocrine carcinoma. PB was focally positive for CD56 at the periphery of the tumor nests. Four ACCs and one PB exhibited focal CD10 reactivity. This study demonstrated the unique immunohistochemical features of SPT. Our results also suggest that SPT exhibits, at least focally, neuroendocrine differentiation, and that these neuroendocrine markers and CD10 are diagnostically useful.

IgG4-positive plasma cell infiltration in the diagnosis of autoimmune pancreatitis

Autoimmune pancreatitis typically produces an enlarged pancreas with narrowing of the pancreatic duct, and can mimic carcinoma. Autoimmune pancreatitis usually responds to corticosteroid treatment, making it important to differentiate from pancreatic ductal adenocarcinoma. Affected patients often have an elevated serum IgG4. It has been proposed that increased numbers of IgG4-positive plasma cells in tissue might be a marker for the condition. We investigated the role of IgG4 staining in the diagnosis of autoimmune pancreatitis, first in resected pancreas specimens (29 autoimmune pancreatitis, nine chronic alcoholic pancreatitis and 25 pancreatic cancer), then in pancreatic needle biopsies. Immunohistochemical stains for IgG4 were scored as none, mild, moderate or marked, according to published criteria. Moderate to marked numbers of IgG4-positive plasma cells were seen in 21/29 autoimmune pancreatitis patients, and were distributed in and around ducts, in interlobular fibrous tissue and in peripancreatic fat. In contrast, eight of nine examples of chronic alcoholic pancreatitis and 22/25 ductal adenocarcinomas had scores of none or mild. When we subdivided autoimmune pancreatitis into the histologic subtypes lymphoplasmacytic sclerosing pancreatitis and idiopathic duct-destructive pancreatitis, 16/17 lymphoplasmacytic sclerosing pancreatitis had moderate to marked staining, compared to five to 12 idiopathic duct-destructive pancreatitis. Needle biopsies from nine patients suspected of having autoimmune pancreatitis had increased numbers of IgG4 cells. We conclude that pancreatic tissue from patients with autoimmune pancreatitis often shows moderate or marked infiltration by IgG4-positive plasma cells (>10/HPF). This is particularly so in the subtype we have designated lymphoplasmacytic sclerosing pancreatitis. We rarely see IgG4 staining in patients with chronic alcoholic pancreatitis and pancreatic ductal adenocarcinoma. IgG4-positive plasma cells are a useful marker for the tissue diagnosis of autoimmune pancreatitis.

Histopathologic and clinical subtypes of autoimmune pancreatitis: the honolulu consensus document.

Autoimmune pancreatitis (AIP) has been extensively reported from Japan, Europe and the USA. While the descriptions of AIP from Japan have predominantly been based on the presence of a distinct clinical phenotype, reports from Europe and the USA describe at least 2 histopathologic patterns in patients diagnosed with AIP, namely lymphoplasmacytic sclerosing pancreatitis (LPSP) and idiopathic duct-centric pancreatitis (IDCP) or granulocytic epithelial lesion- positive pancreatitis. While the 2 entities share common histopathologic features (periductal lymphoplasmacytic infiltration and peculiar periductal fibrosis), expert pathologists can accurately distinguish them on the basis of other unique histopathologic features. Clinically, the 2 entities have a similar presentation (obstructive jaundice/pancreatic mass and a dramatic response to steroids), but they differ significantly in their demography, serology, involvement of other organs and disease relapse rate. While LPSP is associated with elevation of titers of nonspecific autoantibodies and serum IgG4 levels, IDCP does not have definitive serologic autoimmune markers. All experts agreed that the clinical phenotypes associated with LPSP and IDCP should be nosologically distinguished; however, their terminology was controversial. While most experts agreed that the entities should be referred to as type 1 and type 2 AIP, respectively, others had concerns regarding use of the term ‘autoimmune’ to describe IDCP.

Colorectal Cancer With Mutation in BRAF, KRAS, and Wild-Type With Respect to Both Oncogenes Showing Different Patterns of DNA Methylation

PURPOSE BRAF mutations are common in sporadic colorectal cancers (CRCs) with a DNA mismatch repair (MMR) deficiency that results from promoter methylation of hMLH1, whereas KRAS mutations are common in MMR proficient CRCs associated with promoter methylation of MGMT. The aim of this study was to further investigate the link between genetic alterations in the RAS/RAF/ERK pathway and an underlying epigenetic disorder. PATIENTS AND METHODS Activating mutations of BRAF and KRAS were identified and correlated with promoter methylation of 11 loci, including MINT1, MINT2, MINT31, CACNA1G, p16(INK4a), p14(ARF), COX2, DAPK, MGMT, and the two regions in hMLH1 in 468 CRCs and matched normal mucosa. RESULTS BRAF V599E mutations were identified in 21 (9%) of 234 CRCs, and KRAS mutations were identified in 72 (31%) of 234 CRCs. Mutations in BRAF and KRAS were never found in the same tumor. CRCs with BRAF mutations showed high-level promoter methylation in multiple loci, with a mean number of methylated loci of 7.2 (95% CI, 6.6 to 7.9) among 11 loci examined (P < .0001). Tumors with KRAS mutations showed low-level promoter methylation, and CRCs with neither mutation showed a weak association with promoter methylation, with an average number of methylated loci of 1.8 (95% CI, 1.5 to 2.1) and 1.0 (95% CI, 0.79 to 1.3), respectively. CONCLUSION In CRC, the methylation status of multiple promoters can be predicted through knowledge of BRAF and, to a lesser extent, KRAS activating mutations, indicating that these mutations are closely associated with different patterns of DNA hypermethylation. These changes may be important events in colorectal tumorigenesis.

IgG4‐related disease: Historical overview and pathology of hematological disorders

IgG4‐related diseases comprise a recently recognized systemic syndrome characterized by mass‐forming lesions in mainly exocrine tissue that consist of lymphoplasmacytic infiltrates and sclerosis. There are numerous IgG4‐positive plasma cells in the affected tissues, and the serum IgG4 level is increased in these patients. The present study describes the history, autoimmune pancreatitis (AIP), IgG4‐related lymphadenopathy and lymphomagenesis based upon ocular adnexal IgG4‐related disease. Lymphoplasmacytic sclerosing pancreatitis, a prototypal histological type of AIP, is now recognized as a systemic IgG4‐related disease. Lymph node lesions can be subdivided into at least five histological subtypes, and systemic IgG4‐related lymphadenopathy should be distinguished from multicentric Castlemans disease. Interleukin‐6 and CRP levels are abnormally high in multicentric Castlemans disease, but are normal in the majority of systemic IgG4‐related lymphadenopathy. Ocular adnexal IgG4‐related disease frequently involves bilateral lacrimal glands swelling, and obliterative phlebitis is rare. Moreover, some malignant lymphomas, especially mucosa‐associated lymphoid tissue lymphoma, arise from ocular adnexal IgG4‐related disease. In addition, IgG4‐producing lymphoma also exists.

Biliary intraepithelial neoplasia: an international interobserver agreement study and proposal for diagnostic criteria

Cholangiocarcinoma of the intrahepatic and extrahepatic bile ducts develops through a multistep histopathologic sequence. Premalignant or non-invasive neoplastic lesions of bile ducts have been historically called biliary dysplasia or atypical biliary epithelium. To this date, no standard terminology or classification system has been offered for these lesions. In 2005, a conceptual framework and diagnostic criteria for biliary intraepithelial neoplasia (BilIN) were proposed using the livers of patients with hepatolithiasis. We report herein an international interobserver agreement study on the diagnosis of biliary non-invasive neoplastic lesions with the goal to obtain a consensus on the terminology and grading. Seventeen pathologists from the United States, Europe and Asia participated in this study. They shared a digital file containing histological pictures of 30 foci of non-invasive neoplastic lesions selected from the biliary system of patients suffering from primary sclerosing cholangitis, choledochal cyst or hepatolithiasis. In the criteria, we proposed in 2005, BilIN was classified into three categories based on the degree of atypia: BilIN-1, BilIN-2 and BilIN-3. In this study, consensus was reached for the terminology of BilIN and the three-grade classification system. Interobserver agreement on the diagnosis was moderate (κ-value=0.45). On the basis of the suggestions and opinions obtained from the 17 participants, the original criteria for BilIN were revised. We now propose a new consensus classification of BilIN that may assist in allowing a more uniform terminology for the diagnosis of biliary non-invasive neoplastic lesions. This classification should help to advance clinical and research applications.

Clinical diagnostic criteria of IgG4-related sclerosing cholangitis 2012

BackgroundIgG4-sclerosing cholangitis (IgG4-SC) patients have an increased level of serum IgG4, dense infiltration of IgG4-positive plasma cells with extensive fibrosis in the bile duct wall, and a good response to steroid therapy. However, it is not easy to distinguish IgG4-SC from primary sclerosing cholangitis, pancreatic cancer, and cholangiocarcinoma on the basis of cholangiographic findings alone because various cholangiographic features of IgG4-SC are similar to those of the above progressive or malignant diseases.MethodsThe Research Committee of IgG4-related Diseases and the Research Committee of Intractable Diseases of Liver and Biliary Tract in association with the Ministry of Health, Labor and Welfare, Japan and the Japan Biliary Association have set up a working group consisting of researchers specializing in IgG4-SC, and established the new clinical diagnostic criteria of IgG4-SC 2012.ResultsThe diagnosis of IgG4-SC is based on the combination of the following 4 criteria: (1) characteristic biliary imaging findings, (2) elevation of serum IgG4 concentrations, (3) the coexistence of IgG4-related diseases except those of the biliary tract, and (4) characteristic histopathological features. Furthermore, the effectiveness of steroid therapy is an optional extra diagnostic criterion to confirm accurate diagnosis of IgG4-SC.ConclusionThese diagnostic criteria for IgG4-SC are useful in practice for general physicians and other nonspecialists.