[Diffuse pulmonary meningotheliomatosis]

In two patients with bilateral micronodular pulmonary changes a diffuse pulmonary meningotheliomatosis was found. A 73-year-old woman presented with bilateral disseminated miliary pulmonary nodules as a radiological incidental finding. The surgical lung biopsy showed multiple tiny nodular proliferations meningothelial-like cells, corresponding "minute pulmonary meningothelial-like nodules", MPMN. A 60-year-old lady with similar radiological findings showed also proliferations of meningothelial-like cells in a transbronchial cryo-biopsy. These lesions are well known to pathologists as curious isolated incidental findings on histological examination of lung specimens. The here described diffuse form of these changes is very rare; its knowledge is important for the differential diagnosis with neoplastic proliferations and other diffuse parenchymal diseases of the lung. This rare diagnosis is made on histological grounds and is also possible in transbronchial biopsies when careful correlation with clinical and radiological data, knowledge of the entity and adequate specimens are provided.