The pathology of frozen shoulder: A chronic inflammation mast cell mediated proliferative fibrosis

Authors: G.C.R. Hand, T. Matthews, N.A. Athanasou, A.J. Carr

References: SECEC 2005

Abstract
AIMS: This study aims to elucidate the cellular components in the pathology of frozen shoulder using histological and immunocytochemical techniques.

MATERIAL: 23 patients with a diagnosis of primary frozen shoulder resistant to conservative treatment underwent manipulation under anaesthetic and arthroscopic release of the rotator interval. Biopsy material from the rotator interval was taken at time of release. Histological and immunocytochemical analysis was performed to identify the cell types present. Slides were stained with haematoxylin and eosin, Toluidine blue and Congo red for histological analysis. Immunocytochemical analysis was performed with antibodies directed against the following, CD45 (Leucocyte common antigen LCA), CD3 (T cells), CD20 (B cells), CD68 (macrophages), Lyve 1 (lymphatics), S100 (nerve cells), PC10 and MIB1 (proliferative cell markers), Vimentin, alpha smooth muscle actin (ASMA), Calponin (F-actin and tropomyosin) and mast cell tryptase.

RESULTS: The tissue was highly vascular with lymphatics and nerves present, the cell type was characterised by proliferating fibroblasts and chronic inflammatory cells. The chronic inflammatory cell infiltrate was predominantly made up of mast cells, with T lymphocytes and macrophages also evident.

CONCLUSION: The pathological process in frozen shoulder includes chronic inflammation and fibroblastic proliferation which may be a mast cell mediated response.