Early gastric cancer with lanthanum deposition mucosa by endoscopic submucosal dissection: a case report and literature review.

Lanthanum carbonate is used to prevent hyperphosphatemia in dialysis patients with chronic renal failure and generally recognized as poorly absorbed by the gastrointestinal tract. However, some clinical cases of lanthanum deposition in the stomach have been shown. In addition, few endoscopic images of lanthanum deposition have been reported, particularly with respect to early-stage gastric cancer. A 64-year-old man with 22 years history of dialysis was treated with lanthanum carbonate for 3 years. With screening esophagogastroduodenoscopy, he was diagnosed with intramucosal gastric cancer, surrounded by the specific endoscopic images of the lanthanum deposition, and underwent endoscopic submucosal dissection. Histopathologically, massive accumulations of macrophages containing fine, granular, eosinophilic materials were observed in the lamina propria. These eosinophilic depositions were present in the lamina propria of the non-tumor region, but not in that of the tumor region. The histological features were further identified as lanthanum phosphate deposition by scanning electron microscopy. This case indicates the clinical significance of lanthanum deposition associated with gastric cancer. It is further required to evaluate more endoscopic images of the gastric mucosa, especially intramucosal cancer, with lanthanum deposition.