Focal iron sparing mimicking liver lesion in post-transfusion iron overload: A case report.

Iron sparing, a rare imaging phenomenon in the context of hepatic iron overload, can mimic true liver lesions and pose significant diagnostic challenges-especially in oncologic patients with a history of frequent blood transfusions. We present the case of a 68-year-old woman with metastatic breast cancer and transfusion-dependent anemia who developed hepatic iron overload following multiple red blood cell transfusions. MRI showed a hyperintense lesion in segment 4b on a fat-suppressed Dixon sequence, raising initial concern for pathology. T2* mapping and chemical shift imaging revealed hepatic iron overload with relative sparing in segment 4, characterized by a marked signal drop on in-phase imaging and reduced T2* relaxation time in the surrounding liver parenchyma; the spared region itself showed a comparatively longer T2* time, consistent with focal iron sparing rather than a true lesion. Additionally, an aberrant right gastric vein supplying this region suggested altered perfusion as a possible underlying mechanism. This case underscores the importance of identifying focal iron sparing to prevent misdiagnosis and avoid unwarranted interventions.