[Paravertebral hematopoietic pseudotumor during Paget's disease (author's transl)]

Extramedullary hematopoiesis is usually secondary to a severe and prolonged reduction in medullary functions, but can be the rare consequence of an extrusion of tissue formed of weakened or fractured bone. The hematopoietic nature of this pseudotumor can be confirmed histologically or, as in this case of Paget's disease, by Indium scintigraphy which can define the specific locations of the hematopoietic marrow.