CASE 3084 Published on 30.06.2005

Chondromyxoid fibroma

Section

Musculoskeletal system

Case Type

Clinical Cases

Authors

Álvarez M, Bello MJ, Soler R, Rodríguez E

Patient

21 years, male

Categories
No Area of Interest ; Imaging Technique MR
Clinical History
A patient presented with a swelling of the left knee, which developed slowly.
Imaging Findings
The patient complained of a swelling in the left knee over the past eight months. A plain film radiograph showed a slightly expansile lytic lesion with lobulated and well-defined margins involving eccentrically the proximal metaphysis of the tibia (Fig. 1). On MR imaging, the lesion showed an intermediate signal on T1-weighted images (Fig. 2a), which became homogeneously hyperintense on T2-weighted images (Fig. 2b). After an intravenous injection of Gd-DOTA was given, heterogeneous enhancement could be seen (Fig. 2c). The lesion was surgically removed and a bone allograft was required.
Discussion
A chondromyxoid fibroma (CMF) is the least common of the benign cartilaginous skeletal neoplasms. It is most common in the second and third decades of life. A slowly progressive pain, tenderness and swelling, taking anywhere from 1 week to several years to develop, are the most frequent clinical abnormalities. The typical radiographic findings include an eccentric lytic lesion with a well-defined and often sclerotic margin in the metaphysis of a long tubular bone, especially those in the lower extremities (as seen in 80% of the cases). However, a CMF can have a protean radiographic presentation and can occur anywhere in the skeleton as a benign slow-growing tumour. Extensive periosteal reaction and pathologic fractures are unusual, and calcification is rare. On MR imaging, a CMF has a decreased signal on T1-weighted images and an increased signal on T2-weighted images. A lobular pattern of high signal intensity has been described for a CMF, as in other cartilaginous tumours, although the signal intensity of a CMF will depend on the proportion of the chondroid, myxoid and fibrous tissues. The classical histological feature of this tumour is the presence of stellate or spindle-shaped cells arranged in lobules against a background of myxoid or chondroid tissues. The differential diagnosis of a CMF includes, the possibility of a giant cell tumour, an aneurysmal bone cyst and a nonossifying fibroma. The presence of calcification within the tumour suggests other possibilities such as a chondroblastoma and an enchondroma. A surgical resection is the treatment of choice. Because these neoplasms are locally aggressive, wide resection and bone grafting are usually required.
Differential Diagnosis List
Chondromyxoid fibroma.
Final Diagnosis
Chondromyxoid fibroma.
Case information
URL: https://www.eurorad.org/case/3084
DOI: 10.1594/EURORAD/CASE.3084
ISSN: 1563-4086