Pulmonary hyalinizing granuloma: an unusual association with multiple sclerosis.

Pulmonary hyalinizing granuloma (PHG) is a rare entity included in the differential diagnosis of pulmonary nodules of unknown origin. The pathologic entity may represent a peculiar form of pulmonary immune reaction. We report the case of a 40-year-old white woman who had nodular lesions in both lung bases after a 10-year history of multiple sclerosis. An open lung biopsy was required to make the diagnosis. The association of pulmonary hyalinizing granuloma with multiple sclerosis could be coincidental, but since there is a possibility of immune reaction in the pathogenesis of both diseases, the association may be significant.