[The lymphocytoma of the lung. Etiology, pathogenesis, differential-diagnosis and dignity (author's transl)].

Tumor-like lymphoplasias of the human lung are named in different ways and differently classified according to their characteristic features: inflammatory, benign, semi-malignant, and malignant. From the cellular point of view the term "lymphocytoma" is appropriate. There are different stages in the course, each respresenting characteristic histological pictures. An early symptom is a strong lymphatic hyperplasia in the walls of small bronchia followed by a voluminous lymphoplasmacellular infiltration of the interalveolar septa with formation of follicles containing germinal centres. The interstitial infiltration may periodically become more "colored" by facultative participation of basophil stem cells, macrophages, reticular cells, eosinophiles and multinucleated giant cells. The alveolar epithelium reacts with hypertrophy and hyperplasy and finally the alveoles are totally obliterated. Fibroses and hyalinoses develop in later stages. Clinically and morphologically they bear a close relationship to the inflammatory lymphoma Saltzstein and to the lymphoid interstitial pneumonia Liebow. Probably there are transitorial stages between these diseases. The cause is to be seen in immunological reactions of the lymphoepithelial system of the lung. Antigens contact immunocompetent cells at the tonsilla pulmonis. Thus the lymphoplasia is put into action. Is the noxa not diminished it may be followed by the formation of autoantibodies, which support the chronic course. The process can become independent and in that way assume the character of a tumor. Such cases may be named immunocytoma.