Musculoskeletal Tumour Mimics

Giant Schmorls Node A degnerative condition involving herniat ion of intervertebral disc into the adjacent vertebral body via the endplate. Well defined lucent lesion with a sclerotic margin on C T / X - r a y . S i g n a l characeteristic on MRI follow t h a t o f t h e a d j a c e n t intervertebral disc.

Fibrous Dysplasia A localised defect in osteoblastic differentiation and maturation with fibrous stroma and immatore woven bone seen instead of normal bone. On plain film it is seen as a well defined lesions that are usely ground glass matrix and can be often lucent/cystic or sclerotic. No evidence of periosteal reaction. A sclerotic rind is frequently seen. MRI appearances are variable - in this case a cystic component and sclerotic rind without periosteal reaction was demonstrated.

Vascular Thrombosis On MRI heterogenous signal on T2 and T1 was seen with areas of increased T1 in k e e p i n g w i t h f a t . A v i d c o n t r a s t enhancement was demonstrated. Given its atypical appearances it was excised and the histopathology was in keeping with a thrombosed vessel.

Chronic Sclerosing Osteomyelitis of Garre Chronic low activity infection causes ossifying periostitis with subperiosteal bone formation as demonstrated on the plain film. In addition the MRI will demonstrate increased STIR and variable  contrast enhancement can be present if there is ongoing low grade activity. Defects can be seen in the thickened bone in keeping with cloaca where necrotic/infected material drains through

ALVAL Aseptic lymphocyte-dominant vasculitis a s s o c i a t e d l e s i o n ( m e t a l - o n - m e t a l pseudotumour). On M R I w e l l d e f i n e d masses with mixed s o l i d a n d c y s t i c component can often be seen. Typically a low intensity rim is evident as in this case.

Intramuscular Haemangioma On ultrasound a well defined mass with hypoechoic areas and vascular flow is seen and sometimes hyperechoic areas in keeping with. Similar features are demonstrated on MRI with high T2 signal, intermediate T1 with focal fatty areas of increased signal and patchy contrast enhancement.

Muscular Sarcoidosis The great mimicker can have a wide range of presentation. This case presented with resistant hypercalcemia. A PET performed due to suspicion of malignancy demonstrated numerous foci of increased avidity in the muscles of the thigh and upper arm. A biopsy confirmed granulomatous disease.

Odontoid Pannus Fibrovascular granulation tissue due to excessive in f lammatory synovia l p r o l i f e r a t i o n t h a t i s f r e q u e n t l y s e e n i n Rheumatoid Artrititis. In advanced disease it can occur in the cervical spine and cause erosion of the odontoid process. Usually intermediate signal on T1, low on T2 with variable STIR and post contrast appearance depends on the d e g r e e o f a c t i v e inflammation.

Myositis Ossificans Post traumatic lesion with muscles that on plain films can be seen as peripherally calcified lobulated lesions with a cleft between the lesion and the underlying bone often demonstrated. Signal characteritics on MRI will often follow that of bone. 

Morel-Lavallee Occurs in the setting  of trauma and is a closed degloving injury from a shearing force separating skin and subcutaneous fat from the fascia. On ultrasound will be anechoic or hypoehoic and may contain internal debris, fluid levels or hyperechoic globules. MRI will demonstrate the injury and its relationship with the fascia. Fluid levels and globules of fat may be also demonstrated, as seen in this case.

Chronic Insufficiency Fracture Sclerosis and remodelling around a site of fracture can be seen on plain film. In the context of chronicity this can become a little larger and more ill defined.

Dr Matthew Mariathas, Dr Neeraj Purohit, Dr Madeleine Sampson Department of Radiology, University Hospital Southampton

Vascular Inflammation Trauma Auto-immune Metabolic Iatrogenic Neoplasm Degenerative

Giant Bone Island These are bone islands greater than 2cm in diameter. They are found in the medullary cavity. Demonstrate a spiculated margin and blend in with the surrounding trabeculae. No associated soft tissue mass, bone destruction, periosteal reaction or oedema will be seen. Low signal on all MRI sequences like normal cortical bone.