It has been suggested that transient osteoporosis or the bone marrow oedema syndrome (BMOS) may be the initial phase of osteonecrosis of the femoral head (ONFH) and that there may be a common pathophysiology. In this study, we have assessed the MR images of 200 consecutive patients with ONFH in respect of the BMO pattern in order to test this hypothesis. This pattern was not observed in the early stage of ONFH. The initial abnormal finding detected on the MR images was an abnormal band of intensity at the junction between the necrotic area and the normal bone. Structural damage of the head seems to result in the appearance of the BMO pattern and the development of pain in ONFH. There was no finding to support the existence of a continuum between BMOS and ONFH.

ABSTRACT:A 12-year-old castrated male miniature pinscher dog presented with right forelimb lameness. An expansile osteolytic lesion of the right humerus was conspicuous on right forelimb radiographs. Thoracic and abdominal radiographs showed multiple lytic bone lesions on the right scapula, ribs, vertebrae, femurs and pelvis. Additionally, an expansile osteolytic lesion was observed in two thoracic vertebrae and two ribs. Many plasma cells were identified on fine-needle aspiration of the right humerus expansile osteolytic lesion, and monoclonal gammopathy consistent with multiple myeloma was confirmed on serum protein electrophoresis. The expansile osteolytic lesion, an extraordinary radiographic feature of multiple myeloma in dogs, should be considered as a possible radiographic finding of multiple myeloma.