Deposits of lanthanum in the gastric mucosa of a patient with chronic kidney disease

: Lanthanum carbonate is a non-calcium phosphorus chelator used in the treatment of hyperphosphatemia associated with chronic renal disease. Deposits of lanthanum in the gastrointestinal wall have been recently described but its clinical significance is uncertain. We present a case of a 62-year-old male with chronic renal disease treated with lanthanum carbonate for 3 years, with deposits in his gastric mucosa, found on biopsy for dyspepsia. The deposits were acellular and of irregular shape, surrounded by macrophages and foreign body giant cells. The presence of lanthanum in the deposits was confirmed by X-ray spectroscopy. Diagnosis is reached with knowledge of its microscopic appearance and a thorough clinical history.