Microcrystalline cellulose pulmonary embolism and granulomatosis. A complication of illicit intravenous injections of pentazocine tablets.

Four persons had extensive pulmonary granulomatosis from intravenous injections of cellulose derived from tablets intended for oral consumption. Three of these persons were known abusers of pentazocine (Talwin). The principal vascular lesion induced by cellulose is thrombosis. Destruction of arterial elastic laminae and pulmonary vascular dilation commonly ensue. Two of the victims had cor pulmonale. The cellulose crystals induced foreign body granulomas when extravasated subcutaneously at injection sites on the arms, as well as in the right ventricular endocardium. Cellulose crystals have highly characteristic morphology and histochemical staining reactions that facilitate their recognition and their distinction from talc and starch. The latter substances also are used as fillers in tablets and capsules, and lodge in the pulmonary vessels of persons who inject them intravenously.