Granuloma

Granuloma is a medical term for a roughly spherical mass of immune cells that forms when the immune system attempts to wall off substances that it perceives as foreign but is unable to eliminate. Such substances include infectious organisms such as bacteria and fungi as well as other materials such as keratin and suture fragments. A granuloma is therefore a special type of inflammation that can occur in a wide variety of diseases. The adjective granulomatous means characterized by granulomas.