granuloma
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Classification
There are two types of granulomas:
- foreign body granulomas
- immune granulomas
- presence of indigestible particles from organisms
- T-cell mediated immunity
Etiology
diseases associated with the formation of granulomas:
- sarcoidosis
- tuberculosis: granulomas may have a central area of necrosis (caseous necrosis) rare in other granulomatous diseases
- fungal infections
- brucellosis
- tularemia
- syphilis
- leprosy
- Hodgkin's disease
- drug reactions (hypersensitivity pneumonitis)
- vasculitis - granulomatous arteritis
- cat scratch disease
- lymphogranuloma inguinale
- infectious mononucleosis (Epstein Barr virus)
- carcinomas
- occupational exposure
- berylliosis
- silicosis
- zirconium exposure
- talcosis
- Bakelite exposure
- pharmaceutical agents
- foreign body granulomas
- cotton fibers (IV drug use)
- talc
- mineral oil
- hypogammaglobulinemia
Pathology
- microscopic aggregation of macrophages transformed into epithelium-like cells (epithelioid histiocytes) surrounded by lymphocytes & occasional plasma cells
- a focal area of granulomatous inflammation
- epithelioid histiocytes may fuse to form giant cells
- older granulomas develop an enclosing rim of fibroblasts
- most diseases that produce granulomas also produce hilar lymphadenopathy