Dedifferentiated chondrosarcoma of the appendicular skeleton: MRI-pathological correlation.
OBJECTIVE
To correlate the T2-weighted and STIR MRI appearances of dedifferentiated appendicular chondrosarcoma with gross and microscopic pathology.


METHODS
Nine patients with a histologically confirmed diagnosis of dedifferentiated appendicular chondrosarcoma were identified from the Bone Tumour Registry. All patients underwent MRI, including T2-weighted and/or STIR sequences in at least one plane, prior to limb salvage surgery. Areas of reduced signal intensity (SI) compared with hyperintense chondral tumour on the T2-weighted or STIR images were correlated with the resection specimen, to determine the relationship of such out areas of reduced SI with regions of dedifferentiation.


CONCLUSIONS
Patients presented over a period of 7 years. There were five men and four women with mean age 68.2 years and age range 51-78 years. Tumours arose in the femur (6 cases), humerus (2 cases) and tibia (1 case). Three MRI patterns were identified: (1) type 1, a lesion with two distinct signal characteristics-hyperintense chondral and reduced SI dedifferentiated tumour (n=6); type 2, mainly reduced SI lesion-dedifferentiated tumour, with areas of signal void corresponding to matrix calcification (n=2); type 3, a heterogeneous lesion with no radiological evidence of underlying chondral tumour (n=1). T2-weighted or STIR MR sequences can identify areas of dedifferentiation, which should be the preferential site of pre-operative biopsy.
Department of Histopathology, The Royal National Orthopaedic Hospital NHS Trust, Brockley Hill, Stanmore, Middlesex, HA7 4LP, UK.
Fergus
F
MacSweeney
Alan
A
Darby
Asif
A
Saifuddin
D000368:Aged; D001706:Biopsy; D001859:Bone Neoplasms / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology*; D002113:Calcification, Physiologic / Q000502:physiology; D002813:Chondrosarcoma / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D006811:Humerus / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D008131:London; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D015831:Osteochondroma / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology; D012189:Retrospective Studies; D013223:Statistics as Topic; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D014057:Tomography, X-Ray Computed