Anemia after bariatric surgery: the causes sometimes are not related to the surgery

Background - Iron deficiency anemia, pernicious and megaloblastic are common after gastric bypass and biliopancreatic diversion. The main causes are due to duodenal exclusion and anastomotic ulcers. However, low protein diet, vitaminic supplementation, medicines, alcohol and tumors must be remembered. Cases report - The authors relate two cases of severe anemia after bariatric procedures that were diagnosed as metastatic melanoma in small bowel and a colorectal cancer treated surgically with good results. Conclusion - Anemias are common after bariatric surgery, however unusual causes like tumors must be suspected in the elderly and in those patients that clinical treatment didn't have good results.