Fig. 1.
From: Intruding implements: a pictorial review of retained surgical foreign objects in neuroradiology
Foreign body granuloma pathophysiology. The foreign body response begins with rapid neutrophil infiltration and subsequent release of soluble factors involved in monocyte circulating monocyte recruitment. These last differentiate into macrophages, which are activated by T cell lymphocytes-produced interferon-γ. In turn, activated macrophages produce interleukin-1 family cytokines and tumor necrosis factor which determine further macrophage activation and their fusion into multinucleated giant cells. After months, transforming growth factor beta releasing recruits and activates fibroblasts with fibrous capsule development