In vivo characterization of the inflammatory properties of poly(tetrafluoroethylene) particulates.

Suburothelial injections of particulate poly(tetrafluoroethylene) (PTFE) is becoming a widely accepted treatment for a number of urological disorders. Because little is known about the long-term histologic morphology of the injection site, this animal study was performed. Three populations, each consisting of two mongrel dogs, five New Zealand White rabbits, and 10 BALB/c mice, were injected with poly(tetrafluoroethylene) particulate in a glycerine carrier (Polytef Paste) and were followed for a period of 1 week, 3 months, 6 months, and 1 year. Mice received one subcutaneous dorsal injection each, rabbits received two subareolar injections each, and dogs received three subareolar injections each in addition to two periurethral injections. Histologic examination of the biopsy sites revealed a persistent chronic inflammatory reaction with progressive growth of the involved tissue volume. In addition to giant cells and macrophages, lymphocytes became apparent at 3 months and constituted up to 40% of the cellular infiltrate by 1 year. Plasma cells were also noted at the 1-year period in the rabbit model. The progressive growth of the inflammatory pseudo-tumors evoked by injected PTFE may compromise the long-term safety of certain urological procedures involving particulate PTFE.