[Pulmonary hyalinizing granuloma. Apropos of 2 new cases]

Pulmonary hyalinising granuloma are nodular or localised fibrosing lesions of the pulmonary parenchyma and are single or multiple. We report two new cases of this disorder which is rare, as only 62 cases have been published in the literature. It is a pathology with few symptoms, sometimes revealed by general signs. Radiologically there are nodules which are most often round or oval, intra-parenchymal, well demarcated, single or multiple. The histological appearance is characteristic: the centre of the granuloma consists of a network of dense collagen fibres which are lamellar separated by clear spaces; the periphery is the seat of rich cellular infiltration of plasmocytes and lymphocytes in the peri-vascular region. Most often there is a spontaneous benign outcome. The frequent association of pulmonary hyalinising granuloma in fibrotic disorders and the similarity in the histological appearance leads to the hypothesis of a common pathogenesis in these disorders.