Inflammatory pseudotumour of lymph nodes

Abstract

Aim - To describe the clinical, histological and immunohistochemical features in four cases of an uncommon benign lymph node lesion which may mimic a neoplastic process. Methods - Four cases of inflammatory pseudotumour oflymph nodes were studied using conventional staining (haematoxylin and eosin, PAS, Gordon and Sweets reticulin stain, and the Ziehl-Neelsen stain) and with immunohistochemical techniques using a variety of antibodies (CD3, L26, CD15, CD21, CD30, KP1, MAC 387, vimentin, αSMA, HHF-35, D33, CD34, and S100). Results - The lesion comprises a proliferation of spindle cells expanding the connective tissue framework oflymph nodes and is associated with a plasma cell and small lymphocyte infiltrate. There are variable numbers of macrophages, neutrophils and eosinophils, and varying degrees of fibrosis. Vascular changes are common but vary in degree and type. Conclusions - Inflammatory pseudotumour oflymph nodes is an uncommon benign reaction pattern which may be misdiagnosed as a neoplastic or even a malignant process. Increased awareness of its histological features should help prevent such misdiagnoses.