CASE 9738 Published on 21.03.2012

Malignant giant cell tumor of bone

Section

Musculoskeletal system

Case Type

Clinical Cases

Authors

Korzan JR, Murphy DT, Ouellette HA, Munk PL

Vancouver General Hospital,
University of British Columbia,
Radiology;
899 west 12th avenue
v5z1m9 Vancouver, Canada;
Email:peter.munk@vch.ca
Patient

61 years, female

Categories
Area of Interest Musculoskeletal bone, Musculoskeletal joint ; Imaging Technique CT, Conventional radiography, MR
Clinical History
61-year-old female patient with pain in the left knee following fall, unable to weight bear. Conservative therapy was unsuccessful. The patient is otherwise well with no history of prior malignancy. Radiographs, CT and MRI were performed. The preoperative diagnosis was suspicious for malignant giant cell tumour of bone.
Imaging Findings
61-year-old woman with pain in the left knee following fall. Radiographs demonstrated a large lucent lesion within the left tibial metaphysis extending to subchondral bone of the epiphysis, without a definable matrix. CT confirmed the presence of a large radiolucent lesion within the proximal tibia expanding and thinning the lateral cortex with cortical breakthrough. The signal intensity of the lesion was low on T1-weighted images (WI), and was heterogeneously high on STIR WI. After intravenous administration of gadolinium contrast, there was avid peripheral enhancement and central necrosis. The radiographic, CT and MRI appearance were suspicious for giant cell tumor (GCT). Malignant GCT was favored over benign GCT due the aggressive imaging features including soft tissue extension. Metastatic disease was felt less likely. A CT guided biopsy was performed which confirmed malignant giant cell tumor of bone.
Discussion
Giant cell tumour of bone represents approximately 5-10% of primary bone tumours and 18-23% of benign osseous neoplasms [1]. 80% occur in adults between the ages of 20 and 50 years of age. 50-65% of tumours occur in the region of the knee [2]. 2-5% of histologically benign GCT tumours metastasise with the metastatic deposits also having benign histology. Malignant giant cell tumours of bone (MGCTOB) represent 5-10% of giant cell tumours [3]. Radiographic appearances classically are not helpful in predicting clinical behaviour.

Radiographically GCT's are usually metaphyseal-based lucent lesions that extend to epiphyseal subchondral bone without a mineralized matrix. Septations can occur and periosteal reaction is relatively rare. On MRI this lesion is of low signal intensity (SI) on T1 weighted imaging (WI), low to intermediate SI on T2 WI, high SI on STIR WI signal intensity with variable enhancement. Fluid levels within GCT’s can be seen but are non-specific given they can be seen in aneurysmal bone cysts (ABC), chondroblastoma and teleangiectatic osteosarcoma. Malignant GCT can be separated into three categories: a) histologically benign GCT that metastasise, b) primary malignant transformation of benign GCT (dedifferentiated giant cell tumours) and c) secondary malignant transformation of GCT following irradiation or other intervention of a benign GCT. Primary malignant transformation is defined as “a malignant tumour of bone that is composed of sarcomatous overgrowth juxtaposed to zones of typical appearing benign GCT”. Staging systems of GCT are similar: Stage 1 GCT’s have indolent radiographic and histological appearance, Stage 2 lesions appear more aggressive with bony expansion and remodelling, but with an intact periosteum, Stage 3 lesions are more aggressive, with growth and extension into soft tissues but remain benign histologically.

In our case, a CT guided biopsy confirmed malignant giant cell tumour of bone. The lesion was treated with wide excision and reconstruction with a total knee arthroplasty.
Differential Diagnosis List
Histologically confirmed: Malignant giant cell tumour.
Malignant giant cell tumour of bone
Benign giant cell tumour of bone
Final Diagnosis
Histologically confirmed: Malignant giant cell tumour.
Case information
URL: https://www.eurorad.org/case/9738
DOI: 10.1594/EURORAD/CASE.9738
ISSN: 1563-4086

If you wish to reproduce any part of this Eurorad case, please contact us at epc@eurorad.org with your request to obtain official permission.