Metal deposition in post-surgical granulomas of the urinary tract

Fourteen cases of post-surgical granulomatous inflammation of the urinary tract were studied to investigate the possible deposition in the tissues of metals derived from the diathermy instruments used. The granulomas showed central necrosis, palisaded histiocytes and giant cells. On electronmicroscopy both amorphous material and electrondense particles were seen in the granulomas. The former appeared to be necrotic tissue. The particles were metallic in nature. Energy dispersive analysis of X-rays showed the presence of tungsten, iron, copper, nickel, chromium, zinc and vanadium. Tungsten particles were always pure. Other single particles contained two or more of the remaining elements, indicating the presence of alloy metals. Analysis of the diathermy instruments showed the cutting loops to be pure tungsten and the 'rollerballs' to be nickel silver containing copper, zinc, nickel, manganese and iron. Both the loops and balls are supported on stainless steel wires containing iron, chromium, nickel, manganese, molybdenum, copper and vanadium. It is proposed that metallic fragments from the instruments were deposited in the tissues during the surgical procedures and elicited an immunological reaction with granuloma formation. Tungsten is probably inert but nickel, chromium, copper and zinc are immunogenic. Under certain circumstances both nickel and chromium may also be carcinogenic.