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Case Reports
. 2013 Sep 25:11:241.
doi: 10.1186/1477-7819-11-241.

A popliteal giant synovial osteochondroma mimicking a parosteal osteosarcoma

Andreas Toepfer  1 , Florian Pohlig, Heinrich Mühlhofer, Florian Lenze, Rüdiger von Eisenhart-Rothe, Ulrich Lenze
Affiliations
Case Reports

A popliteal giant synovial osteochondroma mimicking a parosteal osteosarcoma

Andreas Toepfer et al. World J Surg Oncol. .

Abstract

Both giant synovial osteochondroma and parosteal osteosarcoma are rare musculo-skeletal tumors, often localized in the vicinity of the knee. Misdiagnosis of a malignant bone tumor can entail fatal consequences. Etiology of giant synovial osteochondroma is widely unsolved but is believed to originate from synovial chondromatosis, a mostly benign metaplasia of the synovial membrane. Parosteal osteosarcoma is a low-grade surface osteosarcoma with a propensity of local recurrence and the potential of distant metastasis and therefore requiring a different therapeutical approach. We report the case of a popliteal giant osteochondroma mimicking a parosteal osteosarcoma. Relevant facts of this rare entity regarding pathogenesis, treatment, and differential diagnoses will be discussed.

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Figures

Figure 1
Figure 1
Anterior-posterior plain radiograph of the lesion.
Figure 2
Figure 2
Lateral plain radiograph of the lesion.
Figure 3
Figure 3
T1-weighted (A) and T2-weighted (B) sagittal MR image of the lesion (arrow).
Figure 4
Figure 4
T1-weighted SPIR sequence, transversal cross-sectioning with gadolinium contrast medium enhancement.
Figure 5
Figure 5
Whole-body bone scintigraphy.
Figure 6
Figure 6
Macroscopic specimen after excisional biopsy.
Figure 7
Figure 7
Sawcuts of the lesion and the attached tendon-like soft tissue nodule (arrows).
Figure 8
Figure 8
Second specimen, EVG-staining, 2.5× microscopic magnification.
Figure 9
Figure 9
EVG-staining, 16× microscopic magnification of the hyalinous cap of the primary lesion.
Figure 10
Figure 10
Exemplary lateral radiograph of a parosteal osteosarcoma, loco typico.
See this image and copyright information in PMC

References

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