[Immunohistochemical studies on pathogenetic features of diffuse fasciitis].

Three cases of diffuse fasciitis were reported: case 1, a 24-year-old female, case 2, an 18-year-old male and case 3, a 61-year-old male. Their prominent features were reduced extensibility of the muscle and/or fascia. Skin was taut and bound underneath in cases 1 and 3, and focal edema was noted in the left forearm of case 2. Firmness of the muscle and/or fascia was dominantly seen in four extremities in case 1, proximal limbs in case 2 and in the trunk and proximal limbs in case 3. Muscle weakness was not seen in case 1, slight in the limbs of case 2 and moderate in the proximal limbs of case 3. Transient eosinophilia was observed in case 1. IgG was elevated in all 3 cases and IgM in cases 1 and 3. Antinuclear antibody was positive in case 1 and 2, and anti-ENA antibody in case 3. Remarkable thickening of the fascia and perivascular mononuclear cell infiltration in the fascia were main pathological features in all three cases. Inflammatory alteration of the muscle was modest and limited to the perifascicular and epimysial sites underneath the fascia. In these 3 cases, a diagnosis of Shulman syndrome or diffuse fasciitis with eosinophilia was made, although eosinophils were scarce in the fascia or muscle tissue. All 3 cases well responded to the oral prednisolone. Mononuclear cells clustered mainly in the perivascular sites, comprising mostly T cells, helper T cells, and partly B cells. These findings suggest that helper T cell mediated immune mechanism may play a pathogenetic role in this disease.(ABSTRACT TRUNCATED AT 250 WORDS)