[Pulmonary hyalinizing granuloma diagnosed by thoracoscopy].

A 36-year-old woman was examined by our hospital for pulmonary coin shadows in both lungs, as disclosed on chest X-ray films. She had no subjective complaints other than allergic rhinitis, but exhibited hypergam-maglobulinemia, particularly in IgE. Inhalative allergen tests were positive for three types of allergens, but no autoimmune disease was detected. Although transbronchial and percutaneous fine needle biopsies failed to obtain enough specimens because of the wandering shadow a thoracoscopic biopsy was effective because of the subpleural location of the target lesions. The histologic findings were consistent with pulmonary hyalinizing granuloma, with extensive, hyalinized lamellar collagen bundles arranged haphazardly in the central area. Infiltration by lymphocytes and plasma cells, together with the destruction of bronchiolar and vessel walls, were observed in the marginal areas. No amyloid deposits or lymphocytic monoclonality were observed in the lesion. Twenty-five months after the biopsy, the patient's clinical and radiographic data had not changed.