Imaging characteristics of tenosynovial giant cell tumors on 18F-fluorodeoxyglucose positron emission tomography/computed tomography: a retrospective observational study

Abstract

Background 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) is useful for assessing location, metastasis, staging, and recurrence of malignant tumors. Tenosynovial giant cell tumor (TSGCT) is a benign tumor; however, some studies have reported that TSGCTs have a high uptake of FDG. Few studies have reported on the detailed evaluation of TSGCT using 18F-FDG-PET/CT. The purpose of the current study is to evaluate the image characteristics and locations, particularly where possible, with or without, extra-articular invasion from TSGCT of the knee in 18F-FDG-PET/CT could occur. Methods We retrospectively reviewed the patients with TSGCT who were diagnosed pathologically either by biopsy or surgical specimen. Furthermore, we evaluated the difference of the maximum standardized uptake value (SUVmax) between diffused TSGCT with extra-articular invasion and TSGCT with intra-articular localization in the knee. Results The study consisted of 20 patients with TSGCT. The mean SUVmax of TSGCT was 12.0 ± 6.50. There were five patients with TSGCT arising in the knee with extra-articular invasion and six with TSGCT with intra-articular localization. The mean SUVmax of TSGCT with extra-articular invasion and those with intra-articular localization were 14.3 ± 6.00 and 5.94 ± 3.89, respectively. TSGCT with extra-articular invasion had significantly higher SUVmax than TSGCT with intra-articular localization (p < 0.05). Conclusions TSGCT revealed high FDG uptake. Furthermore, SUVmax was higher in diffused TSGCT with extra-articular invasion than in intra-articular localized TSGCT; this may reflect its local aggressiveness.

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

“…Surprisingly, these findings were consistent with those in our case. No large cohorts on the advantages of PET/CT in diagnosing this malignancy have been published; however, in our case, the mean SUV max was 12.0 ± 6.50 in TSGCT, 5 which makes it impossible to differentiate between CCS and TSGCT. As SUV max was reported to be high in our case, PET may be advantageous for detecting recurrence and metastasis 6 .…”

Diagnostic Superiority of Dual-Time Point [18F]FDG PET/CT to Differentiate Malignant from Benign Soft Tissue Tumors

“…First, patient recruitment was performed at the discretion of the multidisciplinary oncology team. Therefore, possible selective bias occurred by recruiting benign tumors with clinical and/or MRI criteria of local aggressiveness, such as tenosynovial giant cell tumors or desmoid tumors [51,52]. Moreover, some tumors with pure myxoid content at MRI were not evaluated by [ 18 F]FDG PET/CT (no significant uptake).…”

Giant Cell Tumor of Soft Tissue: An Updated Review

“…Positron emission tomography (PET) imaging has been reported in only limited cases and demonstrates increased fluorodeoxyglucose (FDG) uptake, with high standard uptake values [7,14,18]. Similarly, it has been recognized that giant cell-rich tumors, such as TSGCT and GCTB, have a high accumulation of FDG [24,25], resulting in false-positive diagnoses of malignancy on PET.…”