Myelofibrosis:: an unusual presentation of vitamin D-deficient rickets

We present the case of a breast-fed 5-month-old infant who presented with pancytopenia, secondary to intense myelofibrosis during the winter months because of undiagnosed rickets. The patient responded to oral vitamin D with rapid resolution of symptoms. Secondary hyperparathyroidism was the probable cause of the myelofibrosis. Conclusion Although nutritional rickets remains a problem in developing countries, children in northern climates in industrialized countries may also be at risk. Rickets must be considered when assessing myelofibrosis in a very young child.