[ Magnetic resonance imaging in the early diagnosis of bone marrow necrosis]

Bone marrow necrosis (BMN) is a rare entity characterised by fever and bone pain, accompanied by hypercalcemia and increased LDH. Amorphous eosinophilic material is present in the bone marrow aspirate, with isolated cells in different degrees of necrobiosis. These are frequently post-mortem findings, appearing in up to 19.8% of all autopsies, mostly after haematological malignancies with proliferative features (acute leukaemia, lymphoma). In general terms, BMN is regarded as a poor prognosis sign. Bone gammography with Tc has been included among the diagnostic procedures, in an attempt to carry out an early detection of BMN and to determine its spread. Magnetic resonance imaging (MRI) has recently been regarded useful to evaluate bone marrow involvement in this condition. A 53 year-old woman is presented here who, two and a half years after being diagnosed of mantle cell lymphoma, and having a relapse on her neck lymph nodes, presented severe bone pain showing no radiological evidence of osseous involvement. MRI showed ample spongy marrow involvement of her lower spine, sacrum and pelvic bones. Both femoral heads were preserved, hypointense images being observed in T1, whereas subcortical, hyperintense ones appeared in T2. Bone marrow aspirate showed poor cellularity, with different degrees of necrobiosis on a stippled background. The picture was interpreted as BMN secondary to non-Hodgkin's lymphoma.