PMC3277477_01
Representative scans done upon diagnosis and during the course of sunitinib treatment. (A) Diagnostic computed tomography showing the multilobulated chondrosarcoma mass arising from his right pelvis. (B) Superimposed fluorine-18- fluorodeoxyglucose-positron emission tomography and computed tomography scans showing the pelvis mass (white arrow) immediately prior to sunitinib, two months after initiation of sunitinib alone and two months after combined sunitinib and proton beam radiation. Intensity of fluorine-18-fluorodeoxyglucose uptake: red, high; yellow, intermediate; blue, low.
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F1
We present the case of a 32-year-old Caucasian man who initially presented five years previously with right hip pain and was found at that time to have a large multilobulated mass arising from his right ilium and extending to his right sacrum with involvement of his gluteal musculature (Figure 1A). A positron emission tomography/computed tomography (PET/CT) scan showed uptake to an standardized uptake value (SUV) maximum of 9.0 in the right sacral lesion with two other areas of uptake in his pelvis (Figure 1B). A PET/CT scan obtained two months after the initiation of sunitinib showed improvement in the fluorine-18-fluorodeoxyglucose (FDG)-avidity of the lesions, with a right sacral lesion showing an SUV of 6.8 (Figure 1B). A total of six months after initiating sunitinib, our patient continued to show improvement on imaging, with a PET/CT scan revealing stable non-hypermetabolic pulmonary nodules and improvement in the right sacral lesion with an SUV of 3.4 (Figure 1B).
Hematoxylin and eosin staining of sections from our patient's pelvic tumor mass and skull metastasis. (A) Low-power photomicrograph demonstrating the low-grade chondrosarcoma (black arrows) arising in the stalk of a pre-existing osteochondroma (white arrows). (B) Focally within the stalk of the osteochondroma, the tumor had features of clear cell chondrosarcoma. (C) The skull metastasis consisted entirely of the clear cell chondrosarcoma component.
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F2
Subsequently, a right hemipelvectomy was performed, and the diagnosis of grade 1 chondrosarcoma arising from a pre-existing osteochondroma was confirmed (Figure 2A). Additionally, a minor component of clear cell chondrosarcoma was identified at the origin of the osteochondroma within the medullary cavity of the underlying ileum (Figure 2B). A bone scan showed uptake in his left temporal bone and an excisional biopsy confirmed recurrence of the clear cell chondrosarcoma (Figure 2C).