A specific type of chronic inflammatory response characterized by a localized accumulation of epithelioid macrophages, multi nucleate giant cells, and lymphocytes. These are formed in response to certain micro-organisms in specific infections (e.g. in tuberculosis, leprosy, syphilis), against foreign particles (e.g. retained sutures), or as part of the immune response (e.g. Crohn's disease or sarcoid); this type of chronic inflammation is termed granulomatous inflammation. Granulomas associated with tuberculosis are characterized by central necrosis (caseation). The term granuloma is also sometimes given to an accumulation of granulation tissue at particular sites and in these circumstances it should not be confused with granulomatous inflammation. For example, granulation tissue at the apex of a tooth (periapical granuloma) occurs in response to an infected or non-vital pulp and appears radiographically as a radiolucency with a well defined border. Eosinophilic granuloma is a localized form of Langerhans cell histiocytosis typically occurring in bone. A giant cell granuloma is a lesion characterized by accumulations of multinucleate giant cells in a cellular haemorraghic stroma which may arise on the gingivae (peripheral giant cell granuloma) (see also epulis) or within the jaws (central giant cell granuloma). In bone they appear as a multilocular radiolucency in young individuals and may cause pain and bone swelling. They are treated by curettage. Histologically they cannot be distinguished from lesions caused by hyperparathyroidism (see also brown tumour). A pyogenic granuloma has the same histology as a pregnancy granuloma (epulis) but occurs in both males and females and in any location. It is characterized by a rapid growth of vascular granulation tissue in response to plaque, calculus, or trauma such as the border of a denture (denture granuloma). Treatment is to remove the cause and excision if this fails to produce resolution. In pregnancy, excision may be delayed until after the baby is born.