Necrotizing granulomatous inflammation is a term pathologists use to describe a pattern of chronic (long-standing) inflammation. A granuloma is a small, round collection of specialized immune cells that stick together to both surround and remove a harmful agent from the body. The immune cells in a granuloma include lymphocytes, histiocytes, and multi-nucleated giant cells. The histiocytes in a granuloma are described as “epithelioid” because they stick together in a way that is similar to epithelial cells. Necrotizing refers to dead cells seen at the centre of the granuloma. In contrast, a non-necrotizing granuloma has no dead cells at its centre.
Necrotizing granulomas are notable because they are more likely to be present in infections, such as tuberculosis or fungal infections. As a result, your pathologist may order additional special stains such as a silver stain or acid-fast stain to look for infectious organisms. Necrotizing granulomas may also be seen in some types of vasculitis.