Blue Rubber Bleb Nevus Syndrome Presenting as Severe Transfusion-Dependent Anemia in an Elderly Patient: An Unusual Cause of Lower Gastrointestinal Bleeding.

Blue rubber bleb nevus syndrome (BRBNS) is a rare vascular disorder characterized by venous malformations involving the skin and gastrointestinal (GI) tract. GI involvement may lead to chronic bleeding and iron deficiency anemia, most commonly presenting in younger individuals. We report the case of an 83-year-old male presenting with progressive fatigue and severe anemia (hemoglobin 5 g/dL), requiring multiple blood transfusions. His medical history was significant for recurrent anemia and prior gastrointestinal bleeding. Upper endoscopy was unremarkable; however, colonoscopy revealed multiple bluish, compressible venous malformations scattered throughout the ascending and transverse colon, consistent with BRBNS. Capsule endoscopy excluded small bowel involvement. Given the diffuse distribution and number of lesions, endoscopic or surgical intervention was not feasible. The patient was managed conservatively with blood transfusions and close outpatient follow-up. BRBNS is typically diagnosed in childhood, and adult presentation, particularly in the elderly, is uncommon. Gastrointestinal lesions are more prone to bleeding than cutaneous lesions and may lead to chronic transfusion-dependent anemia. Diagnosis requires a high index of suspicion, especially in patients with recurrent unexplained anemia and negative initial investigations. Management remains challenging and depends on disease extent, ranging from conservative measures to endoscopic, surgical, or pharmacologic therapies. This case highlights an unusual late presentation of BRBNS with isolated colonic involvement and emphasizes the importance of considering vascular malformations in the differential diagnosis of obscure gastrointestinal bleeding in elderly patients.