PET monitoring of clear cell sarcoma of tendons and aponeuroses

A Rare Clinical Presentation With a Difficult Imaging Diagnosis of an Intra-articular Clear Cell Sarcoma of the Knee

ABSTRACT

Clear cell sarcoma, a highly aggressive cell sarcoma with melanotic differentiation, typically occurs in the tendon and aponeuroses of the lower extremities and rarely develops in the intra-articular region. Herein, we present an extremely rare case of clear cell sarcoma originating from the intra-articular knee and suspected as benign tumors due to the benign-looking findings on MRI and PET/CT. The image results in our case were completely consistent with a tenosynovial giant cell tumor, resulting in the misdiagnosis. For differential diagnosis, especially malignant melanoma, histopathology, including IHC and FISH, was indispensable.

18F-FDG PET/CT in Clear Cell Sarcoma With Multiple Bone Metastases

ABSTRACT

A 26-year-old man presented with right facial pain for more than 20 days. Admission diagnosis was considered as jaw osteomyelitis. CT of the chest before surgery showed multiple bone destructions, which were considered as bone metastases. Then the 18F-FDG PET/CT was recommended for finding the primary tumor and evaluation of disease extent. 18F-FDG PET/CT revealed multiple abnormal foci at the skeleton and the left arm. Pathological examination and molecular analysis revealed the diagnosis of clear cell sarcoma. We present a case of clear cell sarcoma with multiple bone metastases, which is an extremely rare tumor.

FDG PET/CT findings in rare sarcomas

The role of FDG PET/CT in management of soft tissue and bone sarcomas has been described in many studies up-to-date. However, contribution of PET/CT to diagnosis and treatment in some types of sarcomas that are seen with low incidence has not been identified properly yet. Clear cell sarcoma, synovial sarcoma of chest and myxoid lyposarcoma are rare types of sarcomas. We aimed to describe the FDG uptake patterns of these rare tumors and find out the role of FDG PET/CT in management of disease.

Clear-cell sarcoma of the small intestine detected by FDG-PET/CT during comprehensive examination of an inflammatory reaction

Clear-cell sarcoma (CCS) is a rare, malignant, soft-tissue tumor, which involves the extremities, particularly the foot and foot joint tendons and aponeuroses. It is morphologically similar to but histochemically distinct from malignant melanoma. CCS arising in the gastrointestinal tract has rarely been reported. The prognosis of CCS is reportedly poor because of the high incidence of metastases at the time of initial diagnosis and the high frequency of recurrence. We report a case of early-stage CCS of the small intestine detected by (18)F-fluoro-2-deoxy D-glucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT) during the comprehensive examination of an inflammatory reaction. In this case, FDG-PET/CT clearly visualized the lesion, which was difficult to detect by contrast CT.