Kappa light-chain amyloidosis of gastrointestinal tract

A 65-year-old man with no previous medical history presented to our hospital with hematochezia. The patient’s vital signs were normal. Physical examination revealed nothing remarkable except left lower quadrant tenderness. Laboratory data indicated mild anemia. Upper endoscopy revealed small erosion in the esophagus (Fig. 1A), mild linear erythema in the lesser curvatures of the gastric body (Fig. 1B), and normal appearance of the mucosa in the duodenum. Colonoscopy revealed multiple submucosal hematomas (Fig. 1C) and ulcerations (Fig. 1D). Biopsies were taken from the stomach and the colonic lesions. Histopathological examination with Congo red staining revealed amorphous eosinophilic infiltrates, while immunostaining revealed found the cells to be positive for kappa light chain (Fig. 2) and negative for lambda chain and amyloid A. The patient was diagnosed with systemic kappa amyloid light-chain (AL) amyloidosis given the involvement of heart and kidney. The patient was transferred to the hematology department and received chemotherapy