Radiohistology and histochemistry of barium granuloma of the colon and rectum.

Barium granuloma of the colon and rectum is a rare complication of X-ray examination of the digestive tract using barium. The authors report 5 new cases occurring in the last 3 years. Histological examination revealed a granulomatous reaction with greyish finely granular refractile PAS-negative material located in the cytoplasm of histiocytes and in the interstitial space. The radiographic study of the paraffin blocks confirmed the nature of this material, which was X-ray opaque, and this was corroborated histochemically with the rhodizonate technique.