Inflammatory pseudotumour (inflammatory myofibroblastic tumour) of the pancreas: a report of six cases associated with obliterative phlebitis

Aims: To describe in detail an uncommon pancreatic condition, which general ly presents with cholestasis and a mass lesion suspicious of malignancy, an d which is characterized histologically by proliferation of fibrous tissue with associated moderate or marked inflammation, as well as obliterative ph lebitis. Methods and results: Out of a consecutive series of 23 pancreaticoduodenect omy specimens which on histological evaluation were found to contain no mal ignant tumour, six cases characterized by the features mentioned above were identified and investigated further. Poor circumscription, firm consistenc e, histology of dense sclerosis with scattered round cell infiltrates and a ssociated obliterative phlebitis and often perineural accentuation of infla mmation were the distinguishing features. On the basis of available histolo gical evidence, the term inflammatory pseudotumour perhaps remains the term best suited to designate this entity since it sums up its two most distinc tive features. However, the possibility that this lesion is in fact a neopl astic process with reactive inflammation (inflammatory myofibroblastic tumo ur) cannot be ruled out on the basis of the histology, and remains a seriou s consideration in view of the proven neoplastic nature of lesions with ver y similar histology arising elsewhere in the body. Importantly, none of the pancreatic lesions reported here recurred or progressed (five informative cases, median follow-up time 70 months). Conclusions: Inflammatory pseudotumour (inflammatory myofibroblastic tumour ) of the pancreas may closely mimic pancreatic adenocarcinoma clinically an d radiologically.