Differential Diagnosis of Lipomatous Tumors Using 18F-Fluorodeoxygulcose Positron Emission Tomography/Computed Tomography: A Retrospective Observational Study.

Background/Aim: Lipomatous tumors, including lipomas, atypical lipomatous tumors (ALTs), myxoid liposarcomas (MLs), and dedifferentiated liposarcomas (DLs), are often diagnosed using magnetic resonance imaging (MRI). Differential diagnosis of lipomas and ALTs by MRI is often challenging. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has recently been used for the diagnosis and evaluation of tumor staging and recurrence of soft tissue tumors. The maximum standardized uptake value (SUVmax) is positively associated with malignant grade in several cancers. This study aimed to evaluate SUVmax of 18F-FDG PET/CT in the differential diagnosis of lipomatous tumors. Patients and Methods: Patients who underwent 18F-FDG PET/CT for the diagnosis of lipomatous tumors between January 2013 and September 2021 were included in the study. Patients with lipomatous tumors, confirmed by pathological diagnosis or surgical specimens, were evaluated for lipomatous tumor SUVmax. Results: This study included 44 patients with lipomas (n=19), ALTs (n=12), MLs (n=9), and DLs (n=4). The mean SUVmax of lipomas, ALTs, MLs, and DLs was 0.99±1.41, 1.92±0.95, 5.21±4.94, and 9.29±1.43, respectively. Lipomas showed a significantly lower SUVmax than did ALTs, MLs, and DLs (p<0.05). ALTs demonstrated a significantly lower SUVmax than did MLs and DLs (p<0.05). No significant differences were observed between MLs and DLs. Conclusion: Lipomas or ALTs had a significantly lower SUVmax than lipomatous sarcomas. Lipomas had a significantly lower SUVmax than ALTs, aiding in their preoperative differentiation. 18F-FDG-PET/CT could serve as a potent tool for the differential diagnosis of lipomatous tumors.

Intraoperative cone-beam computed tomography-guided curettage for osteoid osteoma.

Recently, cone-beam computed tomography (CBCT)-guided surgeries have been developed for bone and soft tissue tumors. The present study aimed to evaluate the efficacy of CBCT-guided curettage for osteoid osteoma. Our study population included 13 patients who underwent primary curettage for osteoid osteoma using intraoperative CBCT in a hybrid operating room between April 2019 and November 2022. We collected the following data: sex, age, follow-up period, symptom onset to time of surgery, tumor size and location, length of skin incision, operating time, radiation dose, recurrence, postoperative complications, and visual analog scale for pain during the last follow-up. There were 10 male and 3 female patients, and the mean age was 25.0 years (range, 9-49 years). The mean follow-up period was 10.6 months (range, 0.4-24.0 months). The locations of the tumors were the proximal femur in 6 patients, the acetabular region in 2 patients, and the ilium, tibial shaft, calcaneus, cuboid, and talus in 1 patient each. The mean time of symptoms onset to surgery was 18.7 months (range, 2.3-69.9 months). The mean maximum diameter of the tumor was 5.9 mm (range, 3.5-10.0 mm). The mean length of the skin incision was 2.2 cm (range, 1.5-3.5 cm). The mean operating time was 96.9 minutes (range, 64-157 minutes). The mean dose of radiation was 193.2 mGy (range, 16.3-484.0 mGy). No recurrences, postoperative complications, and reoperation were observed in this study. All the patients reported 0 mm on the visual analogue scale for pain on the last follow-up. CBCT-guided curettage for osteoid osteoma was minimally invasive and reliable. This procedure can be effective for the treatment of lesions found in deep locations such as the pelvic bone and proximal femur or an invisible lesion that cannot be detected by regular fluoroscopy.

Denosumab administration for bone metastases from solid tumors: a retrospective cross-sectional study.

BACKGROUND: Little is known on how denosumab reduces skeletal-related events (SREs) by bone metastases from solid tumors. We sought to evaluate the effect of denosumab administration in patients with bone metastases from solid tumors. METHODS: Data of patients treated with denosumab were collected from electronic medical charts (n = 496). Eligible participants in this study were adult patients (age ≥ 18 years) with metastatic bone lesions from solid tumors treated with denosumab. SREs, surgical interventions, the spinal instability neoplastic score (SINS) for spinal region, and Mirels' score for the appendicular region were evaluated. To assess whether denosumab could prevent SREs and associated surgery, the SINS and Mirels' score were compared between patients with and without SREs. RESULTS: A total of 247 patients (median age, 65.5 years old; median follow-up period, 13 months) treated with denosumab for metastatic bone lesions from solid tumors were enrolled in this study. SREs occurred in 19 patients (7.7%). SREs occurred in 2 patients (0.8%) who took denosumab administration before SREs. Surgical interventions were undertaken in 14 patients (5.7%) (spinal and intradural lesions in five patients and appendicular lesions in nine patients). The mean SINS of patients without SREs compared to those with SREs were 7.5 points and 10.2 points, respectively. The mean Mirels' scores of non-SREs patients and those with SREs were 8.07 points and 10.7 points, respectively. Patients with SREs had significantly higher Mirels' score than non-SREs patients (p < 0.01). Patients with SREs had higher SINS than non-SREs patients (p = 0.09). CONCLUSIONS: SREs occurred in patients with higher SINS or Mirels' scores. Two patients suffered from SREs though they took denosumab administration before SREs. Appropriate management of denosumab for patients with bone metastasis is significant. Surgical interventions may be needed for patients who with higher SINS or Mirel's scores.

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

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.

Reconstructed bone fracture 28 years after hip rotationplasty for Ewing sarcoma: A case report.

Hip rotationplasty is a surgical method used to treat malignant tumors of the proximal femur. A 52-year-old woman, who underwent hip rotationplasty for Ewing sarcoma of the proximal left femur at the age of 24, fell and hit the left buttock. The patient was then admitted to the Department of Orthopedic Surgery, Graduate School of Medicine, University of the Ryukyus. Radiography and computed tomography (CT) revealed a comminuted fracture of the reconstructed bone distally. The patient underwent open reduction and internal fixation (ORIF) and external fixator. External fixation was removed 1 month after the surgery. At two years after surgery, at the latest follow-up, bone union was confirmed by 3-dimensional CT. The combination of ORIF and temporal external fixation was effective for the reconstructed bone fractures after hip rotationplasty.

Reconstruction of the lateral collateral ligament using the plantaris tendon after wide excision of soft tissue sarcoma of the knee: A case report.

An 83-year-old woman presented with a 1-year history of a growing mass on the lateral surface of the right knee. Magnetic resonance imaging revealed a large soft tissue tumor in the subcutis of the right knee. The mass in the right knee rapidly increased, due to hemorrhage from the tumor. A needle biopsy revealed that the diagnosis was synovial sarcoma. The patient underwent wide excision and lateral collateral ligament reconstruction using the plantaris tendon. The patient had a Musculoskeletal Tumor Society Score of 86% at the lateset follow-up. In conclusion, reconstruction of the lateral collateral ligament using the plantaris tendon may be useful for preserving the function of the knee joint after resection of the soft tissue due to sarcoma of the knee.

Packing with alpha-tricalcium phosphate followed by curettage and phenol-ethanol ablation for appendicular giant cell tumor of bone.

Giant cell tumor of bone (GCTB) is an intermediate and locally aggressive bone tumor. Alpha-tricalcium phosphate (alpha-TCP) is an adjustable bone substitute used to fill various sizes of bone cavities after curettage for GCTB. This study aimed to evaluate the surgical outcome of packing with alpha-TCP followed by curettage and phenol-ethanol ablation. We retrospectively reviewed data of 16 patients with GCTB who underwent primary surgery in our institute between January 2009 and April 2021. Data of Campanacci grading system; number of local recurrences and distant metastases; local recurrence-free survival rate using the Kaplan-Meier method; oncological outcomes; and complications after surgery (secondary osteoarthritis and postoperative fracture) were evaluated in this study. Regarding the Campanacci grading system, 2 patients were classified as grade I, 14 as grade II, and none as grade III. The 5-year local recurrence-free survival rate was 77.8% in all cases. Lung metastasis was not detected in this study. Oncological outcomes were: continuous disease free, 13 patients; alive with disease, 3 patients; and no evidence of disease or death of disease, none of the patients. Secondary osteoarthritis after surgery was not detected in the present study. Packing with alpha-TCP followed by curettage and phenol-ethanol ablation for appendicular GCTB may be safe and effective in suppressing the risk of secondary osteoarthritis.