Lanthanum deposition of the gastric mucosa in a dialysis patient.

A 49-year-old man presented for a screening esophagogastroduodenoscopy (EGD) as part of his registration for a donated kidney transplant. He had been on hemodialysis for 4 years for end-stage renal disease (ESRD) due to diabetic nephropathy. He was taking lanthanum carbonate (LaC) for hyperphosphatemia. A plain abdominal radiograph and CT showed the radiopaque appearance of LaC. EGD disclosed whitish spots resembling xanthomas in the stomach. Biopsies showed deposition of granular crystalline-like material and phagocytosis of these by multinucleated giant cells on HE staining. These histiocytes were positive for CD68. La deposition was suspected because of the long-term oral administration of LaC. LaC is commonly used to treat hyperphosphatemia in patients with ESRD. La deposition on the gastric mucosa presents with various endoscopic findings, including whitish spots, annular whitish mucosa, and diffuse whitish mucosa. The gastric endoscopic findings of La deposition reflect the infiltrated histiocytes and not the LC deposition itself. Our case highlights the importance of recognizing the rare but characteristic imaging findings of gastrointestinal La deposition in hemodialysis patients who are taking LaC.

Strongyloides stercoralis hyperinfection presenting pneumatosis intestinalis and acute respiratory distress syndrome after treatment for COVID-19.

A 91-year-old man was admitted with vomiting and abdominal pain. He had had COVID-19 pneumonia a month before and the treatment had consisted of remdesivir, dexamethasone and baricitinib. CT scans showed pneumatosis intestinalis. His respiratory condition rapidly deteriorated and chest CT scans showed ground-glass opacity and Strongyloides stercoralis was identified in the sputum, making a diagnosis of hyperinfection syndrome associated acute respiratory distress syndrome. Treatment of ivermectin was not achieved in time and he died of multiple organ failure. S. stercoralis is a soil-transmitted helminth endemic to tropical and subtropical areas. Immunosuppressive conditions can cause hyperinfection syndrome and life-threatening conditions. Our case highlights the importance of assessing for untreated chronic strongyloidiasis in COVID-19 patients requiring steroid treatment in endemic areas.

Rapid formation of aortoesophageal fistula complicated by mycotic thoracic aortic aneurysm secondary to infective endocarditis.

A 73-year-old man was admitted with four weeks of intermittent fever. He had a history of total aortic arch replacement for aortic arch aneurysm four years prior. CT scans showed no abnormalities before admission. Repeated blood cultures yielded Streptococcus anginosus and Prevotella melaninogenica, suggesting infective endocarditis (IE). Transesophageal echocardiography revealed a vegetation on the aortic valve, confirming IE. He suddenly presented with massive hematemesis and hypotension. Endoscopy revealed an elevated lesion with a laceration but no active bleeding in the esophagus. CT scans showed a thoracic aneurysm involving the esophagus. A diagnosis of aortoesophageal fistula (AEF) complicated by mycotic thoracic aortic aneurysm (MTAA) was made, and he underwent stent graft interpolation followed by minimally invasive esophagectomy. MTAAs are more prone to rupture than arteriosclerotic aneurysms as they are usually not true but pseudoaneurysms. Antecedent infection, including endocarditis, sepsis, predisposes to MTAA. AEF is a rare but life-threatening cause of gastrointestinal bleeding characterized by Chiari's triad. There have been no reports of such rapid formation of AEF after the graft replacement, as shown here. A recent article reported a rapid formation (16 days) of AEF after thoracic endovascular aortic repair, emphasizing prosthetic infection as the most important risk factor. Our case underscores the importance of suspecting AEF and conducting repeated appropriate examinations even if initial examinations do not reveal any aneurysms.