A granuloma is a mass of cells which form when the immune system is trying to fight off a foreign species but can’t eliminate it from the body. It is a type of inflammatory reaction which can occur in the lungs when nanometer-sized particles are inhaled.
I read about this medical term in a chapter of Vicki Grassian’s book “Nanoscience and Nanotechnology.” The chapter entitled “Neurotoxicity of Manufactured Nanoparticles” was authored by the DOGEE seminar speaker Kurt Pennell. The author suggests that these nanometer-sized particles can cause neurological damage because the small particles can cross the blood-brain barrier.