Introduction
Blue rubber bleb nevus syndrome (BRBNS) is a rare congenital disease characterized by multifocal venous malformations, mostly involved in skin and gastrointestinal (GI) tract [1]. The positon of venous malformations can run through the GI tract, and the small intestine is the most common lesion location, which cause chronic occult bleeding and iron deficient anemia (IDA). The diagnosis of BRBNS is developed when typical malformations of venous appears[2], but some cases had underground lesions leading to long term misdiagnosis. Here, we report a case misdiagnosed with refractory IDA for 12 years, who ultimately display the underlying disease of BRBNs uncovered by GI endoscopy and capsule endoscopy.