Extradural, Abnormal Marrow Signal
Kevin R. Moore, MD
DIFFERENTIAL DIAGNOSIS
Common
Vertebral Fracture with Epidural Hematoma
Osteomyelitis, Pyogenic
Metastases, Blastic Osseous
Metastases, Lytic Osseous
Osteomyelitis, Granulomatous
Multiple Myeloma
Plasmacytoma
Lymphoma
Hemangioma
Less Common
Chondrosarcoma
Chordoma
Osteoblastoma
Aneurysmal Bone Cyst
Ewing Sarcoma
Rare but Important
Extramedullary Hematopoiesis
Hemangiopericytoma
Osteosarcoma
Giant Cell Tumor
Echinococcus
ESSENTIAL INFORMATION
Helpful Clues for Common Diagnoses
Vertebral Fracture with Epidural Hematoma
May be seen following any cause of vertebral fracture (traumatic, compression, pathological)
Abnormal marrow signal reflects combination of edema, hemorrhage
Look for fracture line to confirm diagnosis
Osteomyelitis, Pyogenic
Bacterial suppurative infection of vertebrae, intervertebral disc
Ill-defined hypointense vertebral marrow (T1WI), destruction of vertebral endplate cortex on both sides of disc
Paraspinal ± epidural infiltrative soft tissue ± loculated fluid collection
Metastases, Blastic Osseous
Bone production > bone destruction
Lesion centered in posterior cortex initially → pedicle
Hematogenous dissemination (arterial or venous via Batson plexus) > perineural, lymphatic, CSF spread
Metastases, Lytic Osseous
Bone destruction > bone production
Lesion centered in posterior cortex initially → pedicle
Usually enhances diffusely; may mask lesion if fat suppression not used
Osteomyelitis, Granulomatous
Granulomatous (tuberculosis, brucellosis, fungal) infection of spine + adjacent soft tissues
Tuberculosis: Gibbus vertebrae, relatively intact discs, large paraspinal abscesses
Brucellosis: Anterosuperior epiphysitis with associated sacroiliitis
Multiple Myeloma
Multifocal malignant bone marrow proliferation of monoclonal plasma cells
Multifocal diffuse or heterogeneous T1 hypointensity, T2 hyperintensity, variable enhancement
Plasmacytoma
Solitary monoclonal plasma cell tumor of bone or soft tissue
Often lacks specific features to distinguish from solitary hematogenous metastasis
Lymphoma
Lymphoreticular neoplasms with wide variety of specific diseases, cellular differentiation
Protean imaging manifestations often nonspecific
Hemangioma
Typical “benign” (fatty stroma) hemangioma: Hyperintense on T1WI and T2WI MR + contrast enhancement
“Aggressive” hemangioma: Iso- to hypointense on T1WI, hyperintense on T2WI + avid contrast enhancement
Lesion growth, bone destruction, vertebral collapse, absence of fat, active vascular component
May extend epidurally → cord compression
Helpful Clues for Less Common Diagnoses
Chondrosarcoma
Primary or secondary (degeneration of osteochondroma or enchondroma)
Lytic mass ± chondroid matrix, cortical disruption, extension into soft tissues
Tumor cells produce chondroid matrix mineralization with “rings and arcs”
Chordoma
Malignant tumor arising from notochord remnants
Sacrococcygeal > clivus > > vertebral body
Lesion center in posterior vertebral body, marked T2 hyperintensity help distinguish from hematogenous metastasis
Osteoblastoma
Benign, well-circumscribed, expansile lesion of neural arch with osteoid matrix
Peritumoral edema may obscure lesion, mimic malignancy or infection on MR
Aneurysmal Bone Cyst
Expansile neoplasm centered in neural arch containing thin-walled, blood-filled cavities
Fluid-fluid levels 2° hemorrhage, blood product sedimentationRelated posts:
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