Pitfall-to-avoid pharyngeal opacities caused by bismuth subgallate.

Bismuth subgallate is used occasionally as a hemostatic agent for packing the adenoidal and tonsillar beds after an adenotonsillectomy. Containing a heavy metal, it is relatively insoluble and poorly absorbed. It produces faint opacities on plain radiographs and these may mimic a foreign body or pharyngeal calcification. We report a 13-year-old girl with linear radiopacities in the nasopharynx and in the palatine tonsillar bed. Careful and complete clinical information pinpointed the exact (iatrogenic) cause of these radiodensities.