Want to take quizzes and track your credits?
An adolescent girl presented with a 3-month history of a growing, painless mass in the right thigh. A magnetic resonance imaging (MRI) scan showed an inhomogeneous nodule in the subcutaneous layer with a largest diameter of approximately 5 cm. No enlarged lymph nodes were detectable in the groin. Results of a complete blood cell count and levels of alkaline phosphatase, lactic dehydrogenase, and C-reactive protein were unremarkable. An ultrasonography-guided core needle biopsy was performed, and histopathologic evaluation showed the aspects of a small round-cell tumor, which was confirmed to be a Ewing sarcoma by immunohistochemical and molecular analysis (with positivity for the EWS-FLI1 fusion gene [OMIM 133450]). The patient then underwent disease staging with computed tomography (CT) of the chest and whole-body fluorodeoxyglucose positron emission tomography (FDG-PET). The CT findings were negative for secondary lesions; the FDG-PET scan demonstrated, as expected, high uptake in the right thigh (maximum standard uptake variable [SUVmax], 8.4) at the site of the subcutaneous tumor and at a second lesion in the left ankle joint (SUVmax, 12.0). The patient reported vague pain around the left ankle but no functional limitations and no history of trauma at that site. A radiograph of the ankle did not show calcifications within the soft-tissue lesion. An MRI scan of the ankle showed a 1.5-cm soft tissue mass in the posterior recess of the ankle joint with a low to intermediate signal in T1- and T2-weighted sequences and moderate contrast enhancement throughout the lesion (Figure 1).
Please finish quiz first before checking answer.
Read the answer below and download your certificate.
Read the discussion below and retake the quiz.
B. Tenosynovial giant cell tumor
The nodule in the ankle joint with low to intermediate intensity signal on T1- and T2-weighted images and diffuse contrast enhancement was highly suggestive of a tenosynovial giant cell tumor (TGCT). Ganglion cysts appear with a homogeneous high-intensity T2-weighted signal and do not show central contrast enhancement or high uptake on FDG-PET. Synovial sarcoma is a rare soft-tissue tumor that is intra-articular only in about 10% of the cases. This tumor usually shows an inhomogeneous high-intensity signal on T2-weighted MRI scans. A similar radiologic presentation would also be expected in case of a soft-tissue metastasis from an Ewing sarcoma, which is a rare event.1 Synovial sarcoma shows calcifications within the tumor in approximately 30% of cases.
Sign in to take quiz and track your certificates
JN Learning™ is the home for CME and MOC from the JAMA Network. Search by specialty or US state and earn AMA PRA Category 1 CME Credit™ from articles, audio, Clinical Challenges and more. Learn more about CME/MOC
Corresponding Author: Emanuela Palmerini, MD, Medical Oncology, Istituto Ortopedico Rizzoli, Department of Experimental, Diagnostic and Specialty Medicine, Bologna University, Via Pupilli 1, 40136 Bologna, Italy (firstname.lastname@example.org).
Published Online: May 24, 2018. doi:10.1001/jamaoncol.2018.1120
Conflict of Interest Disclosures: Drs Palmerini and Staals reported serving on an advisory board for Daiichi Sankyo. No other disclosures were reported.
You currently have no searches saved.