A rare case of intra-articular synovial sarcoma of the hip joint: a case report with intra-articular findings via hip arthroscopy.

Although synovial sarcoma is a relatively common soft tissue sarcoma, primary intra-articular cases are extremely rare. Herein, we report a case of primary intra-articular synovial sarcoma arising from the hip joint, that was initially treated with hip arthroscopy. A 42-year-old male presented with a history of pain in the left hip for 7 years. Radiography and magnetic resonance imaging revealed the primary intra-articular lesion and simple excision with an arthroscopy was performed. Histological findings revealed spindle cell proliferation with abundant psammoma bodies. SS18 gene rearrangement was confirmed by fluorescence in situ hybridization, and the tumor was diagnosed as synovial sarcoma. Adjuvant chemotherapy and radiotherapy were performed. Local control without metastasis was achieved 6 months after excision. This is the first case of intra-articular synovial sarcoma of the hip joint excised via hip arthroscopy. When an intra-articular lesion is identified, malignancies such as synovial sarcoma should be included in the differential diagnosis.

Rhabdomyosarcoma With FUS::TFCP2 Fusion in the Scalp: A Rare Case Report Depicting Round and Spindle cell Morphology.

Rhabdomyosarcoma (RMS) is a nonepithelial malignant tumor that differentiates into immature skeletal muscle. It is currently classified into 4 main subtypes according to the WHO classification. However, based on clinicopathological and molecular findings, there has been an increasing number of cases that do not fit into any of these subtypes. TFCP2-rearranged RMS is a rare tumor with characteristic clinicopathological findings including a preference for the craniofacial bones, a spindle and epithelioid histomorphology, and positive immunohistochemistry for epithelial markers, ALK, and myogenic markers. In this report, we describe a rare case of RMS with FUS::TFCP2 fusion in the scalp of a 58-year-old man. Histologically, the tumor showed a biphasic pattern, with solid proliferation of round cells in the superficial areas and of spindle cells in the deep areas. Immunohistochemically, tumor cells were positive for pan keratin, myogenic markers (desmin, MYOD1, and myogenin), and ALK. Additionally, fluorescence in situ hybridization using a break-apart FUS probe revealed FUS rearrangement. RMS with FUS::TFCP2 fusion was suspected, and the fusion gene was finally confirmed by target fusion sequencing. We believe that detailed histological, immunohistochemical, and genetic findings were important for the diagnosis. The unique traits of this tumor were the biphasic histological appearance consisting of round and spindle cells and development in the skin and soft tissue.

Effect of Tranilast on the Frequency of Invasive Treatment for Extra-Abdominal Desmoid Fibromatosis.

BACKGROUND: Active surveillance (AS) has been suggested for managing extra-abdominal desmoid fibromatosis (EADF), but a substantial percentage of such patients transitioned to invasive secondary treatments. The anti-keloid medication tranilast is frequently used in Japan but its effectiveness for EADF is not well understood. METHODS: We retrospectively analyzed the medical records of EADF patients treated with tranilast between January 2009 and March 2021. EADF has been reported to shrink spontaneously, so the effects of all drugs must be compared with AS. To assess the effect of tranilast, we compared the clinical courses of patients receiving tranilast with those managed by AS (as identified in a systematic review). A systematic review of AS outcomes was conducted on July 22, 2021, in accordance with PRISMA guidelines. The primary endpoint was rate of conversion to secondary treatment. Secondary endpoints were progression-free survival, objective response rate (ORR), disease control rate (DCR), and adverse events. The rates of conversion to secondary treatment, ORRs, and DCRs were compared between the two groups by using the Fisher exact test. RESULTS: Eighteen patients who received tranilast as initial treatment for EADF were included. Two patients (11.1%) underwent surgical resection for treatment of tumor growth and persistent pain. The rate of conversion to secondary treatment was significantly lower for tranilast than for a pure AS approach (40.1%; p = 0.01). ORR and DCR did not differ between groups. CONCLUSIONS: Tranilast was better than AS for initial management of EADF.

Prevalence and risk factors of preoperative venous thromboembolism in patients with malignant musculoskeletal tumors: an analysis based on D-dimer screening and imaging.

BACKGROUND: Venous thromboembolism (VTE) is a major complication in patients with malignant tumors and orthopedic disorders. Although it is known that patients undergoing surgery for malignant musculoskeletal tumor are at an increased risk of thromboembolic events, only few studies have investigated this risk in detail. Therefore, the aim of this study was to determine the prevalence and risk factors for preoperative VTE in malignant musculoskeletal tumors patients. METHODS: We retrospectively reviewed the medical records of 270 patients who underwent surgical procedures, including biopsy for malignant musculoskeletal tumor, have undergone measurements of preoperative D-dimer levels, and were subsequently screened for VTE by lower extremity venous ultrasonography and/or contrast-enhanced computed tomography scans. Statistical analyses were performed to examine the prevalence and risk factors for VTE. Receiver operating characteristic (ROC) analysis was performed to verify the D-dimer cutoff value for the diagnosis of VTE. RESULTS: Overall, 199 patients (103 with primary soft tissue sarcomas, 38 with primary bone sarcomas, 46 with metastatic tumors, and 12 with hematologic malignancies) were included. D-dimer levels were high in 79 patients; VTE was detected in 19 patients (9.5%). Multivariate analysis indicated that age ≥ 60 years (P = 0.021) and tumor location in the lower limbs (P = 0.048) were independent risk factors for VTE. ROC analysis showed that the D-dimer cutoff value for the diagnosis of VTE was 1.53 µg/mL; the sensitivity and specificity were 89.5% and 79.4%, respectively. CONCLUSIONS: Our study indicated that age and tumor location in the lower limbs were independent risk factors for preoperative VTE in malignant musculoskeletal tumors patients. D-dimer levels were not associated with VTE in the multivariate analysis, likely because they are affected by a wide variety of conditions, such as malignancy and aging. D-dimer is useful for exclusion diagnosis because of its high sensitivity, but patients with high age and tumor location in the lower limbs are a high-risk group and should be considered for imaging evaluation such as ultrasonography regardless of D-dimer levels. TRIAL REGISTRATION: Our study was approved by the institutional review board. The registration number is B200600056 . The registration date was July 13, 2020.

Characteristics of Patients with Giant Cell Tumor of Bone and High Serum Tartrate-Resistant Acid Phosphatase 5b Levels: Comparison of Tumor Volume and Clinical Factors.

BACKGROUND: Serum tartrate-resistant acid phosphatase 5b is well known to be increased in giant cell tumors of bone. However, there are only a few studies that analyzed the association with tartrate-resistant acid phosphatase 5b expression in those patients. Therefore, we analyzed the characteristics of patients with giant cell tumors of bone and high tartrate-resistant acid phosphatase 5b expression. METHODS: This retrospective study included 26 patients with giant cell tumors of bone. The correlation between tartrate-resistant acid phosphatase 5b before initial treatment and tumor volume was evaluated. Patients were divided into two groups according to tartrate-resistant acid phosphatase 5b level. Statistical analysis was performed between the two groups. RESULTS: Tartrate-resistant acid phosphatase 5b was elevated in 17/26 patients, and the mean value was 852 mU/dL. There was no correlation with tumor volume (r = 0.034, P = 0.86). The mean age of 34.5 years in the HT group was significantly younger than the mean age of 47.4 years in the LT group (P = 0.040). Pathologically, 19/26 cases showed at least one focal area with features of typical giant cell tumor of bone. Although 11/18 patients in the LT group exhibited relatively noticeable secondary changes, all patients in the HT group exhibited typical features (P = 0.0074). CONCLUSIONS: Tartrate-resistant acid phosphatase 5b levels were not elevated in some giant cell tumors of bone. This study suggested that tartrate-resistant acid phosphatase 5b may be elevated in younger patients and in cases with fewer pathological secondary changes, regardless of tumor volume.