Pancreatic malignant fibrous histiocytoma, inflammatory myofibroblastic tumor, and inflammatory pseudotumor related to autoimmune pancreatitis: characterization and differential diagnosis
ABSTRACT Malignant fibrous histiocytoma (MFH) and inflammatory myofibroblastic tumor (IMT) are uncommon primary non-epithelial cell tumors of the pancreas. In addition, there are inflammatory pseudotumors (IPT) that may arise in the course of autoimmune pancreatitis (AIP). In the English language literature, only 24 cases of IMT and nine cases of MFH in the pancreas have been reported to date. We investigated three individual spindle cell tumors of the pancreas that were identified as MFH, IMT, and IPT, respectively, using immunohistochemical and molecular analysis. Both the MFH and the IMT, but not the IPT, showed nuclear p53 expression and mutations of the p53 gene. The MFH and the IMT also had higher mitotic and Ki-67 (MIB-1) indexes than the IPT. The IPT was found to be a tumor-like case of AIP. Many IgG4-positive plasma cells, which are considered to be a feature of AIP, were found in all three tumors. It is concluded that in this series of spindle cell tumors of the pancreas, apart from immunohistochemical features, the demonstration of p53 mutations may be helpful in distinguishing true neoplastic tumors from pseudotumors such as IPTs arising in the context of AIP.
- Ground Penetrating Radar, 2004. GPR 2004. Proceedings of the Tenth International Conference on; 02/2004
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ABSTRACT: Chronic pancreatitis is a fibroinflammatory disease of the pancreas. Etiologically, most cases are related to alcohol abuse and smoking. Recently, gene mutations have been identified as the cause of hereditary pancreatitis. Other chronic pancreatitis types that were defined in recent years are autoimmune pancreatitis (lymphoplasmacytic sclerosing pancreatitis) and paraduodenal pancreatitis ('groove pancreatitis', 'cystic dystrophy of heterotopic pancreas'). This review describes and discusses the main histological findings, the pathogenesis and the clinical features of the various types of chronic pancreatitis. In addition, pseudotumors and other tumor-like lesions are briefly mentioned.Modern Pathology 03/2007; 20 Suppl 1:S113-31. DOI:10.1038/modpathol.3800690 · 6.36 Impact Factor
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ABSTRACT: Autoimmune pancreatitis (AIP) is a newly recognized disease. The presence of IgG4 positive plasma cells is thought to be of diagnostic help. In a surgical series of chronic pancreatitis cases, we determined the relative frequency of AIP before and after 1990, analyzed the diagnostic significance of IgG4 expression and examined the presence of oligoclonal T or B-cell populations. The histopathology of 202 surgical specimens of chronic pancreatitis removed between 1975 and 2004 was reviewed and 2 groups were distinguished, 1 of AIP cases and the other of nonautoimmune chronic pancreatitis (non-AIP CP). The intensity of infiltration of pancreatic tissue by IgG4 positive plasma cells and other immune cells was studied immunohistochemically. Finally, T and B-cell clonality was tested by polymerase chain reaction-based analysis. Except for 1 case in 1978, all cases of AIP were observed after 1990. IgG4 positive plasma cells were detected in 72.5% of AIP cases and in 63.1% of non-AIP CP cases. More than 20 cells per high power field were only seen in AIP (sensitivity 43%, specificity 100%). This finding was associated with higher age and grade. Polyclonal T and B-cell populations were found in both AIP and non-AIP CP except for 1 AIP case showing an oligoclonal IgGH-FR3 gene rearrangement. AIP seems to have increased considerably in frequency in the last 2 decades. High density infiltrates of IgG4 positive plasma cells are diagnostic for AIP, but are seen in less than half of the cases. T or B-cell oligoclonality could not be established as a feature of AIP.American Journal of Surgical Pathology 05/2007; 31(4):521-8. DOI:10.1097/01.pas.0000213390.55536.47 · 4.59 Impact Factor