Intratumoral extramedullary hematopoiesis in solitary fibrous tumor of the breast

Extramedullary hematopoiesis (EMH) is most often associated with underlying hematologic disorders, such as myeloproliferative neoplasms and thalassemia. EMH in the setting of solitary fibrous tumor (SFT) is exceedingly rare, with only 3 cases reported to date in the English literature. Herein, we describe our experience with a unique case of SFT arising in the breast with intratumoral foci of EMH in a 57-year-old woman who presented with an incidentally found right axillary mass on routine screening mammography. To the best of our knowledge, this is the first reported case of mammary SFT with concurrent intratumoral EMH.