From Microcytosis to Macrodiagnosis.

A 12-year-old Hispanic girl presented with fatigue, lightheadedness, and intermittent headaches. She was depressed and appeared pale to her mother. Her examination was unremarkable except for palpebral conjunctival pallor and was otherwise noncontributory. She had a profound hypoproliferative microcytic anemia with low iron level, low transferrin saturation, and a normal ferritin level. The patient experienced improvement in clinical symptoms following transfusion of packed red blood cells and oral iron therapy. At follow-up 2 months later, she presented with similar symptoms and persistent microcytic anemia with low iron levels. Her ferritin level was increased along with markedly elevated C-reactive protein and erythrocyte sedimentation rate. An oral iron challenge demonstrated lack of absorption, and hepcidin level was also significantly elevated. Thorough gastrointestinal and rheumatologic evaluations were performed to search for a source of inflammation. Key components of the patient's social history supplemented by serology, radiographic, and pathologic findings ultimately cinched an unexpected diagnosis.