Immunologic abnormalities in two patients with pulmonary hyalinizing granuloma

Pulmonary hyalinizing granuloma (PHG) is a disease of slowly enlarging pulmonary nodules made up of dense bundles of collagen accompanied by an infiltrate of chronic inflammatory cells. The etiology is unknown. Although it has been suggested that the lesions represent an exaggerated immune response to unidentified agents, results of a detailed immunologic work-up of these patients have not been published. This report presents the laboratory findings of two patients with biopsy-proven PHG who have been followed four and eighteen years. Autoantibodies were detected (antinuclear antibody, rheumatoid factor, and positive antiglobulin tests), although clinically there was no evidence of a specific collagen-vascular disorder. Both patients had elevated levels of circulating immune complexes. These data suggest that immune complex mechanisms may be important in the pathogenesis of PHG.