Immunohistochemical analysis of an additional case of focal myositis

We present an additional case of focal myositis which, after surgical excision of the muscular mass, did not evolve to generalized polymyositis. To our knowledge immunological evaluations of this disease have never before been carried out. Immunohistochemical analysis of the muscular mass showed the presence of activated endothelial cells, CD4 and macrophage cells in the perivascular and endomysial areas, suggesting an immune-mediated mechanism of muscular damage. At the same time the normal distribution of the peripheral blood lymphocyte subpopulations and the normal levels of serum IL-1 beta, IL-6, TNF-alpha, soluble IL-2R and soluble CD8 underline the non-systemic nature of the disease.