In these conditions, small inflammatory nodules or granulomas form in affected tissues. The term granuloma comes from a Latin word meaning little grain or granule.
Granulomas are groups of immune cells which are normally part of the body's defence system.
Scientists are unable to say exactly why these granulomas form. Lymph glands elsewhere in the body such as in the neck and in the armpits may also be involved. Sarcoidosis can involve any other organ or tissue in the body including the salivary glands, liver, eyes and skin. The cause is not known. We do, however, know that it is not a cancer or any other sort of malignant tumour.