Microscopic description and IHC:
The esophageal biopsy shows acute esophagitis with associated brown crystalline and fibrillary material consistent with iron deposition. Iron staining is positive in these areas. HSV and PASD stains are negative.
Discussion:
A history of ferrous sulfate ingestion was noted upon review of the medical record. Erosive esophageal mucosal injury from iron tablet ingestion at therapeutic levels is well documented. This condition is found in almost 1% of all upper gastrointestinal endoscopy exams and is important to keep in mind when brown crystalline material is identified in biopsy tissue. The injury is reversible with discontinuation or switching to alternative forms of iron supplementation.