Iron medication-associated gastric mucosal injury

An endoscopic antral biopsy specimen was taken from a 48-year-old, white woman with iron deficiency anemia who was currently taking ferrous sulfate, 250-mg tablets, twice a day. Microscopic examination of the biopsy specimen revealed oxyntic and transitional mucosa with marked crystalline, brown-pigmented material deposited in the superficial mucosa (Figure 1, original magnification 364). Mucosal injury was apparent, including pyknotic nuclei and distortion of the epithelium associated with encrustation of iron material. In addition, focal luminal acute inflammatory exudates and mucosal erosion were evident. An iron stain (Gomori method) confirmed that the brown pigment material was crystalline iron (Figure 2, original magnification 364). The iron stain also highlighted hemosiderin pigment accumulation in the deep fundic glands. No Helicobacter pylori organisms or intestinal metaplasia were identified on special stains (Giemsa and periodic acid‐Schiff/Alcian blue). Oral iron medication has been widely used for prevention and treatment of anemia. It is well recognized that iron overdose can cause severe corrosive injury to the upper gastrointestinal (GI) tract, which includes mucosal necrosis, ulceration, and ischemia. Although mucosal injury that results from iron tablet ingestion at the therapeutic level has been rarely reported, 1,2 it can be seen in approximately 1% of biopsy specimens taken from the upper GI tract, including the esophagus, stomach, and duodenum, during endoscopic examinations. 1 Ferrous sulfate is the most common iron medication associated with the pathologic findings. The diagnosis of iron deposition in the mucosa is straightforward. Material from iron tablets has a characteristic brown crystalline and clumpy fibrillar appearance. It represents oxidized inorganic iron and is refractile but not polarizing. Most of the iron is extracellular. It can be luminal, lying adjacent to the surface epithelium and admixed with luminal fibrinoinflammatory exudates. In addition, crystalline iron is often seen in the lamina propria or granulation tissue or forming iron-containing thrombi in blood vessels. 1,2 The crystalline iron can be easily distinguished from hemosiderin pigments despite positive staining by iron for both substances. The latter is intra