Lanthanum deposition in a dialysis patient.

Lanthanum carbonate (LaCO(3)) is an oral phosphate binder widely used in end-stage renal disease (ESRD). Preclinical animal studies reported the highest La concentrations outside the gut to be in mesenteric lymph nodes. We observed previously unreported La deposition visible by light microscopy and confirmed by scanning electron microscopy with energy dispersive x-ray spectroscopy in a mesenteric lymph node at autopsy of a 38-year-old female ESRD patient 3 years following LaCO(3) administration. Although LaCO(3) is generally thought to be minimally absorbed, this demonstration suggests the need for further investigation of the extent and potential effects of such absorption.