ABSTRACT
Lanthanum carbonate is a phosphate binder that is used to reduce serum phosphate levels in patients with end-stage renal disease (ESRD). Lanthanum forms insoluble lanthanum phosphate complexes that are supposed to pass through the gastrointestinal (GI) tract unabsorbed. Phosphate binders have been reported to deposit in the GI tract and can cause mucosal injury. There are few case reports of GI bleeding associated with phosphate binder deposits. This case report presents a patient with iron deficiency anaemia secondary to biopsy-proven lanthanum deposits in the upper GI tract. There were no overt signs of active GI bleeding. Patient's anaemia improved with discontinuation of the phosphate binder. Lanthanum could be a hidden cause of resistant anaemia among patients with ESRD through asymptomatic GI blood loss.