Intravenous injection of drugs meant for oral administration results in the deposition within lung capillaries, arterioles, or small to medium-size arteries of filler substances or tablet disintegrants, including talc, cornstarch, microcrystalline cellulose, and crospovidone. Talc or other powdery materials used to dilute, or cut, illicit drugs such as heroin can also deposit in the lung vasculature. As a result of the deposit of these foreign materials within the lung vasculature, angiothrombosis or foreign body granulomatous reaction can occur. Pulmonary hypertension is a rare result of long-term drug abuse most likely due to ongoing vascular obstruction.

In transbronchial biopsies from intravenous drug abusers, granulomatous inflammation or foreign body giant cell granulomas may be identified in the lumen and walls of capillaries and arterioles and occasionally in small to medium-size arteries. Granulomas may be found outside of the vasculature, and there may be variable amounts of fibrosis present. Multinucleated giant cells can contain polarizable crystalline foreign material (microcrystalline cellulose); polarizable round particles with a “Maltese cross” pattern (cornstarch); or irregular, platelike, approximately 0.5 to 50 μm polarizable foreign material (talc).