Immunohistochemical analysis of retraction pocket pars tensa of tympanic membrane in children

Immunohistochemical analysis of retraction pocket pars tensa of tympanic membrane in children. Identification of signs typical for cholesteatoma and support of retraction theory of cholesteatoma. Study design: a prospective study analysing 31 surgically removed retraction pockets. University Hospital, Children's Medical Centre Methods: Retraction pockets processed by a standard process for immunohistochemical analysis. The observed findings were specified using antibodies CD45 LCA (leukocyte common antigen), CD31 (platelet endothelial cell adhesion molecule), D2-40 (marker of lymphatic endothelium), MMP9 (marker of degradation of connective tissue extracellular matrix) and Ki67 (cellular marker of proliferation). All observed parameters except for MMP9 had a significantly higher incidence in retraction pocket stage III compared to stage II according to Charachon. We described immunohistochemical signs of retraction pocket pars tensa of tympanic membrane in children resulting in cholesteatoma. All the observed signs occur in the structure of matrix and perimatrix of cholesteatoma. A significantly higher incidence of all observed parameters except from MMP9 was proved in retraction pocket stage III, unlike in stage II. This observation proves the fact that retraction pocket is a progressive disease and is a procholesteatoma stage.