It is a specific type of proliferative inflammation in which the local formation of inflammation is characterized by chronic inflammation mainly by the proliferation of macrophages constituting well-defined nodular lesions. Diseases that are chronic granulomatous inflammation include tuberculosis, leprosy, syphilis, schistosomiasis, histoplasmosis, sarcoidosis, and inflammation caused by foreign bodies such as surgical sutures, asbestos, and talcum powder. The main cellular components of sarcoidosis are epithelioid cells and multinucleated giant cells. In the pathological process of these chronic granulomatous inflammatory diseases, under the long-term stimulation of those undigested bacteria or other antigenic substances, too many macrophages entering the lesion are transformed into epithelioid cells, surrounding the lesion, with scattered multinucleated giant cells between the epithelioid cells. 1, bacterial infection: Mycobacterium tuberculosis and Mycobacterium leprae cause tuberculosis and leprosy, respectively. A gram-negative bacillus can cause cat-scratch disease; 2, spirochete infection: syphilis spirochetes cause syphilis; 3, fungal and parasitic infections: including histoplasmosis and schistosomiasis; 4, foreign bodies: surgical sutures, asbestos and talcum powder; 5, unknown causes: such as nodular disease. Granulomas can be divided into foreign body granulomas and infectious granulomas. Foreign body granulomas are due to foreign bodies that are not easily digested and foreign body irritation that forms chronic inflammation over time. Infectious granulomas, in addition to the aspect that certain pathogenic microorganisms are not easily digested, can also cause an immune response in the body, especially a cellular immune response. The main cellular components of granulomas are epithelioid cells and multinucleated giant cells.