Detection of Novel Tyrosine Kinase Fusion Genes as Potential Therapeutic Targets in Bone and Soft Tissue Sarcomas Using DNA/RNA-based Clinical Sequencing.

BACKGROUND: Approximately 1% of clinically treatable tyrosine kinase fusions, including anaplastic lymphoma kinase, neurotrophic tyrosine receptor kinase, RET proto-oncogene, and ROS proto-oncogene 1, have been identified in soft tissue sarcomas via comprehensive genome profiling based on DNA sequencing. Histologic tumor-specific fusion genes have been reported in approximately 20% of soft tissue sarcomas; however, unlike tyrosine kinase fusion genes, these fusions cannot be directly targeted in therapy. Approximately 80% of tumor-specific fusion-negative sarcomas, including myxofibrosarcoma and leiomyosarcoma, that are defined in complex karyotype sarcomas remain genetically uncharacterized; this mutually exclusive pattern of mutations suggests that other mutually exclusive driver oncogenes are yet to be discovered. Tumor-specific, fusion-negative sarcomas may be associated with unique translocations, and oncogenic fusion genes, including tyrosine kinase fusions, may have been overlooked in these sarcomas. QUESTIONS/PURPOSES: (1) Can DNA- or RNA-based analysis reveal any characteristic gene alterations in bone and soft tissue sarcomas? (2) Can useful and potential tyrosine kinase fusions in tumors from tumor-specific, fusion-negative sarcomas be detected using an RNA-based screening system? (3) Do the identified potential fusion tumors, especially in neurotrophic tyrosine receptor kinase gene fusions in bone sarcoma, transform cells and respond to targeted drug treatment in in vitro assays? (4) Can the identified tyrosine kinase fusion genes in sarcomas be useful therapeutic targets? METHODS: Between 2017 and 2020, we treated 100 patients for bone and soft tissue sarcomas at five institutions. Any biopsy or surgery from which a specimen could be obtained was included as potentially eligible. Ninety percent (90 patients) of patients were eligible; a further 8% (8 patients) were excluded because they were either lost to follow-up or their diagnosis was changed, leaving 82% (82 patients) for analysis here. To answer our first and second questions regarding gene alterations and potential tyrosine kinase fusions in eight bone and 74 soft tissue sarcomas, we used the TruSight Tumor 170 assay to detect mutations, copy number variations, and gene fusions in the samples. To answer our third question, we performed functional analyses involving in vitro assays to determine whether the identified tyrosine kinase fusions were associated with oncogenic abilities and drug responses. Finally, to determine usefulness as therapeutic targets, two pediatric patients harboring an NTRK fusion and an ALK fusion were treated with tyrosine kinase inhibitors in clinical trials. RESULTS: DNA/RNA-based analysis demonstrated characteristic alterations in bone and soft tissue sarcomas; DNA-based analyses detected TP53 and copy number alterations of MDM2 and CDK4 . These single-nucleotide variants and copy number variations were enriched in specific fusion-negative sarcomas. RNA-based screening detected fusion genes in 24% (20 of 82) of patients. Useful potential fusions were detected in 19% (11 of 58) of tumor-specific fusion-negative sarcomas, with nine of these patients harboring tyrosine kinase fusion genes; five of these patients had in-frame tyrosine kinase fusion genes ( STRN3-NTRK3, VWC2-EGFR, ICK-KDR, FOXP2-MET , and CEP290-MET ) with unknown pathologic significance. The functional analysis revealed that STRN3-NTRK3 rearrangement that was identified in bone had a strong transforming potential in 3T3 cells, and that STRN3-NTRK3 -positive cells were sensitive to larotrectinib in vitro. To confirm the usefulness of identified tyrosine kinase fusion genes as therapeutic targets, patients with well-characterized LMNA-NTRK1 and CLTC-ALK fusions were treated with tyrosine kinase inhibitors in clinical trials, and a complete response was achieved. CONCLUSION: We identified useful potential therapeutic targets for tyrosine kinase fusions in bone and soft tissue sarcomas using RNA-based analysis. We successfully identified STRN3-NTRK3 fusion in a patient with leiomyosarcoma of bone and determined the malignant potential of this fusion gene via functional analyses and drug effects. In light of these discoveries, comprehensive genome profiling should be considered even if the sarcoma is a bone sarcoma. There seem to be some limitations regarding current DNA-based comprehensive genome profiling tests, and it is important to use RNA testing for proper diagnosis and accurate identification of fusion genes. Studies on more patients, validation of results, and further functional analysis of unknown tyrosine kinase fusion genes are required to establish future treatments. CLINICAL RELEVANCE: DNA- and RNA-based screening systems may be useful for detecting tyrosine kinase fusion genes in specific fusion-negative sarcomas and identifying key therapeutic targets, leading to possible breakthroughs in the treatment of bone and soft tissue sarcomas. Given that current DNA sequencing misses fusion genes, RNA-based screening systems should be widely considered as a worldwide test for sarcoma. If standard treatments such as chemotherapy are not effective, or even if the sarcoma is of bone, RNA sequencing should be considered to identify as many therapeutic targets as possible.

Cancer may accelerate locomotive syndrome and deteriorate quality of life: a single-centre cross-sectional study of locomotive syndrome in cancer patients.

BACKGROUND: Thanks to recent advancement in cancer treatment, an increasing number of cancer patients are expected to live longer with cancer. The ambulatory ability is essential for cancer patients to spend their own independent lives, but locomotive syndrome (LS), a condition of reduced mobility due to impairment of locomotive organs, in cancer patients has been seldom examined. METHODS: This was a single-institutional cross-sectional study. Cancer patients receiving cancer therapy between April 2020 and March 2021 were asked to participate. LS was classified as stage 0-3, and compared with their performance status (PS). Physical component summary (PCS) and mental component summary (MCS) were calculated from the results of Short Form-8. Logistic regression analysis was performed to identify risk factors for LS stage 3. RESULTS: One hundred and seventy-six cancer patients were included. The rate of LS was 96.0%. That of LS stage 3 was 40.9% and as high as 29.7% even if limited to those with PS 0. The mean PCS and MCS were both inferior to the national averages. PCS decreased as the LS stage advanced. Old age and underweight were revealed as independent risk factors for LS stage 3. CONCLUSIONS: The ratio of LS in cancer patients was extremely high, and the LS stage correlated with physical QOL. Even those with PS 0 can have severe LS; thus, LS can be a sensitive detector of physical disability of cancer patients than PS. The improvement of LS can be a key to the preservation of their ADL and QOL.

[Orthopaedic Management of Bone Metastasis].

Thanks to advancement in cancer therapy, an increasing number of cancer patients are expected to live longer with cancer in Japan. Activities of daily living(ADL)and quality of life(QOL)of cancer patients has become much more important than ever. Because a decline in mobility negatively affects ADL and QOL, the management of locomotive organs of cancer patients is crucial. In 2018, the Japanese Orthopaedic Association decided their annual activity theme as"locomotive syndrome in cancer patients", with the concept of preventing and improving locomotive syndrome for longer and healthier life of cancer patients. Bone metastasis, as a major cause of locomotive syndrome in cancer patients, needs to be evaluated and managed properly for better ADL and QOL of cancer patients. Pathological fractures, spinal instability, and spinal injury cause not only severe pain and massive functional impairment of patients but increased nursing care burden. To resolve these problems, surgery plays a major role. Possible surgical procedures include internal fixation, curettage, cementation, and arthroplasty for the long bones, whereas percutaneous vertebroplasty, decompression, posterior/anterior spinal fusion, and total en bloc spondylectomy for the spine. Less invasive surgical procedure tends to be chosen for a patient with poorer prognosis. The main purpose of bone metastasis surgery is to maintain ADL and QOL of cancer patients hopefully during the remaining survival time; therefore, estimated survival should be considered when determining the surgical strategy. In addition, case-by- case careful peri-operative management is required because cancer therapy can vary widely in patient age, cancer type, and tumor stage. To accommodate the variety of orthopaedic surgeries to the diversity of cancer therapy, the corporation between oncologists and orthopaedic surgeons is indispensable.

Clinical features and treatment outcomes of dedifferentiated and grade 3 chondrosarcoma: A multi-institutional study.

Chondrosarcoma is the second most common primary malignant bone tumor. In this multicenter study, we sought to evaluate the disease-specific survival (DSS) and disease-free survival (DFS), and prognostic factors in patients with dedifferentiated chondrosarcoma (DDCS) or grade 3 chondrosarcoma (G3CS) in Japan. We retrospectively investigated the treatment outcomes and prognostic factors in 62 patients with DDCS and 19 patients with G3CS at 15 institutions participating in the Japanese Musculoskeletal Oncology Group. We also clarified significant clinicopathological factors for oncological outcomes. In surgery for primary lesions aimed at cure, a histologically negative margin (R0) was obtained in 93% (14/15) of patients with G3CS and 100% (49/49) of patients with DDCS. The 5-year DSS was 18.5% in patients with DDCS and 41.7% in patients with G3CS (p = 0.13). Local control was obtained in 80% (12/15) and 79.6% (39/49) of patients with G3CS and DDCS in the primary lesion after surgery with a wide surgical margin, respectively. In multivariate analysis, stage and no treatment/palliative treatment for the primary lesion were independent prognostic factors for DSS of DDCS, and age and no treatment/palliative treatment for DSS of G3CS. The 5-year DFS rate was 22.8% in 26 patients with DDCS who did not receive adjuvant chemotherapy, and 21.4% in 14 patients who received adjuvant chemotherapy. The prognosis of DDCS remains poor, although R0 resection was carried out in most cases. Effective and/or intensive chemotherapeutic regimens or agents should be considered or developed for patients with high-grade chondrosarcoma, particularly for those with DDCS.

Short-term clinical outcomes of Kyocera Modular Limb Salvage System designed cementless stems for the endoprosthetic reconstruction of lower extremities: a Japanese Musculoskeletal Oncology Group multi-institutional study.

BACKGROUND: The high rate of aseptic loosening of cemented stems has led to their frequent use in endoprosthetic reconstruction. However, problems, such as stem breakage and stress shielding at the insertion site, remain. The Japanese Musculoskeletal Oncology Group (JMOG) has developed Kyocera Modular Limb Salvage System (KMLS) cementless stems with a unique tapered press-fit and short fixation design. This study aimed to clarify the short-term postoperative outcomes of this prosthesis and validate the stem design. METHODS: One hundred cases of KMLS cementless stems (51 male patients; median age, 49 years; mean follow-up period, 35 months), with a minimum follow-up of 2 years, for the proximal femur (PF), distal femur (DF), and proximal tibia were prospectively registered for use. Prosthesis survival, complication rates, postoperative functional, and radiographical evaluation were analyzed. Complications or failures after insertion of the KMLS endoprostheses were classified into five types and functional results were analyzed according to the MSTS scoring system at postoperative 1 year. The diaphyseal interface and anchorage were graded by the ISOLS system at postoperative 2 years. RESULTS: The overall prosthesis survival rates at 2 and 4 years were 88.2 and 79.6%, respectively. The prosthesis-specific survival rate excluding infection and tumor recurrence was 90.2 and 87.9%, respectively. Younger age (p = 0.045) and primary tumor (p = 0.057) were associated with poor prognosis of prosthesis-specific survival excluding infection and tumor recurrence. Complications were observed in 31 patients, 13 patients underwent revision surgery. The mean MSTS functional score at 1 year postoperatively was 68%. Early implant loosening was significantly more common in the DF (p = 0.006) and PF/DF straight stem (p = 0.038). The ISOLS radiographic evaluation at 2 years after surgery revealed good bone remodeling and anchorage in most cases (bone remodeling: 90% / excellent and good, anchorage: 97% / excellent and good). CONCLUSIONS: Tumor endoprosthesis long-term fixation to the diaphysis of the lower extremity remains challenging. The KMLS cementless stem with a unique tapered press fit design showed good short-term results in maintaining bone stock. To prevent early loosening, a curved stem should be used in PF and DF, but long-term follow-up is necessary.

Clinical Outcomes of Patients with Metastatic Solitary Fibrous Tumors: A Japanese Musculoskeletal Oncology Group (JMOG) Multiinstitutional Study.

BACKGROUND: Although the unpredictable malignant behavior of solitary fibrous tumors (SFTs) has been recognized, the clinical features and prognosis of metastatic SFTs have not been well documented due to the extreme rarity of these cases. The aim of this study is to investigate the clinical features, prognostic factors, and optimal management of patients with metastatic SFTs. PATIENTS AND METHODS: Sixty patients with metastatic SFT were retrospectively reviewed. Univariate and multivariate analyses were performed to identify the factors associated with survival. Time to next treatment (TNT) was used to evaluate the effects of various chemotherapy regimens. RESULTS: A total of 34 male and 26 female patients (median age 55 years, range, 23-87 years) were included in the study. The median follow-up period after metastasis was 32 months (range 1-126 months). Tumor location and local recurrence were correlated with late metastasis. The 3- and 5-year overall survival rates were 72.7% and 49.2%, respectively. Primary tumor location, number of metastases, and metastasectomy were significantly associated with survival. Metastasectomy was the only significant variable on multivariate analysis. The TNT was significantly different among the various regimens. CONCLUSIONS: Patients with metastatic SFTs had relatively longer survival periods compared with those with other metastatic soft-tissue sarcomas. Tumor location and number of metastases was associated with survival. Surgical resection of the metastatic lesions offers the best chance of survival, however further studies are warranted to define patients who would benefit from metastasectomy, and the most effective chemotherapeutic regimen for patients with metastatic SFTs remains unknown.

Cytological features of BCOR-CCNB3 sarcoma: Comparison with Ewing sarcoma and synovial sarcoma.

INTRODUCTION: BCOR-CCNB3 sarcoma (BCS) is one of the histological types classified as an undifferentiated small round cell sarcoma of bone and soft tissue. This sarcoma frequently develops in males under 20 years of age. Histologically, a delicate capillary network has been reported as a conspicuous finding. In this study, the cytological findings of BCS were observed in two cases of primary lesions and one case of a lung metastatic lesion. The cytological findings of BCS were compared with its histological mimics, and the characteristic findings of BCS were examined. METHODS: Three cases of BCS were studied, and a cytological comparison was performed with 8 cases of Ewing sarcoma (ES) and 10 cases of synovial sarcoma (SS; monophasic type: 7 cases, biphasic type: 2 cases, poorly differentiated: 1 case). RESULTS: In all BCS cases, small clusters with thin and delicate vascular cores and tiny vascular fragments were conspicuous. In ES and SS cases, although small clusters with vascular cores were observed, the vascular cores were thicker than in BCS, and no tiny vascular fragments appeared in most cases. Cytomorphological differences of tumour cells were also observed among BCS, ES, and SS. Predominantly rounded nuclei with fine chromatin and inconspicuous nucleoli can be cytological clues for BCS. CONCLUSIONS: BCS shows characteristic cytological findings that make the diagnosis of BCS more likely than that of ES and SS. Cytological evaluation is a useful tool for appropriate differential diagnosis that leads to a more accurate final diagnosis and rapid treatment.

Temporal hemiarthroplasty for distal femoral osteosarcoma in early childhood: a case report.

BACKGROUND: Prosthetic reconstruction for distal femoral osteosarcoma is challenging for younger children. We herein report a successful case of limb-sparing surgery for a younger patient with distal femoral osteosarcoma requiring osteo-articular resection. CASE PRESENTATION: A 5-year-old girl with high-grade conventional osteosarcoma in the left distal femur underwent a series of surgeries. After three cycles of neoadjuvant chemotherapy, limb-salvage surgery was planned because femoral rotationplasty had been refused. At 6 years and 2 months old, distal femoral resection and temporary spacer insertion using a 7-mm-diameter intramedullary nail and molded polymethylmethacrylate was performed. At 7 years and 8 months old, secondary surgery was performed because the first spacer had been dislocated and the residual femur became atrophic. The distal end of the residual femur was removed by 1 cm, but the periosteum and induced membrane around polymethylmethacrylate was preserved. In order to stabilize the spacer against the tibia, a custom-made ceramic spacer with a smooth straight 8-mm-diameter stem was utilized. The bone-spacer junction was fixed with polymethylmethacrylate and then covered with the preserved periosteum and induced membrane. After surgery, the bone atrophy improved. At 9 years and 7 months old, the second spacer was removed because it had loosened, and the knee joint was reconstructed using a custom-made growing femoral prosthesis with a curved porous 8.5-mm-diameter stem. Cancellous bone tips from the proximal tibia were grafted around the bone-prosthesis junction underneath the induced membrane. At 10 years and 5 months old, the patient was able to walk unsupported and a radiograph showed further thickening of the cortex of the residual femur without any stress shielding. Although having 5 cm of limb length discrepancy, the patient and her mother were satisfied with the function. The MSTS score was 24 out of 30 points. Repeated limb length extensions are planned. CONCLUSIONS: This case report provides an example of limb-salvage surgery after distal femoral resection in a small child. The use of a temporary spacer utilizing partial cementation and preservation of the periosteum and induced membrane appears to afford a viable limb-salvage option after distal femoral resection for younger children.

Prediction of the pathological fracture risk during stance and fall-loading configurations for metastases in the proximal femur, using a computed tomography-based finite element method.

BACKGROUND: It is important to assess the fracture risk associated with metastasis in the proximal femur. The study aimed to clarify the effect of tumor location on the risk of pathological fracture of the proximal femur and investigate the fracture risk not only in the stance-loading configuration (SC), but also in the fall-loading configuration (FC) using a computed tomography (CT)-based finite element (FE) method based on a simulated metastatic model. METHODS: The axial CT scans of the proximal femora of non-osteoporotic healthy men (n = 4; age range, 42-48 years) and osteoporotic post-menopausal women (n = 4; age range, 69-78 years) were obtained with a calibration phantom, from which the three-dimensional FE models were constructed. A single 15-mm-diameter spherical void simulating a tumor was created at various locations from the neck to subtrochanteric level. Nonlinear FE analyses were performed. RESULTS: The mean predicted fracture loads without spherical voids in the SC were 7700 N in men and 4370 N in women. With the void at the medial femoral neck and in the region anteromedial to lesser trochanter, the mean predicted fracture load significantly reduced to 51.3% and 59.4% in men and 34.1% and 64.5% in women, respectively. The mean predicted fracture loads without a spherical void in the FC were 2500 N in men and 1862 N in women. With the void at the medial and posterior femoral neck, the predicted fracture load was significantly reduced to 65.7% and 79.7% in men and 48.3% and 65.4% in women, respectively. CONCLUSIONS: These results showed that the risk of pathologic fracture was quite high in both the SC and FC when the lytic lesion existed along the principal compressive trabecular trajectory or posterior neck. Prophylactic intervention should be considered for metastases at these locations.

Atypical and malignant granular cell tumors in Japan: a Japanese Musculoskeletal Oncology Group (JMOG) study.

BACKGROUND: Malignant granular cell tumors (MGCTs) are extremely rare neoplasms with only a limited number of studies published to date. The aim of this study is to elucidate the clinicopathological characteristics and prognostic factors of MGCTs. METHODS: This is a multi-institutional retrospective study of MGCTs with a central pathological review. A total of 18 cases were retrieved. Specimens were blindly reviewed by two pathologists based on the diagnostic criteria by Fanburg-Smith et al. Kaplan-Meier survival probabilities were calculated, and risk factors for poor prognosis were evaluated. RESULTS: Three and fifteen cases were diagnosed as atypical GCTs (AGCTs) and mGCTs according to the Fanburg-Smith et al. classification, respectively. Four (one atypical and three malignant) cases had metastasis at the first presentation, including lymph node metastasis. Three out of ten cases treated with wide resection developed local recurrence. Although prolonged static disease periods of ≥1 year were observed in four cases receiving chemotherapy, all cases with local recurrence or metastasis, including two atypical cases, eventually died of disease. The 5- and 10-year overall survival rates for localized MGCTs were 69.2 and 34.6 %, respectively. The presence of necrosis was revealed as a risk factor associated with adverse clinical outcomes. CONCLUSIONS: MGCTs have high rates of recurrence and metastasis including lymph node metastasis. As histologically atypical cases also have metastatic potential, close attention should be paid to AGCTs. The combination of histological evaluation and tumor size may lead to more accurate diagnosis of this rare neoplasm.

Intramedullary nailing has sufficient durability for metastatic femoral fractures.

BACKGROUND: Surgical treatment options of femoral metastases include intramedullary nailing (IMN) and endoprosthetic reconstruction (EPR). Previous studies have demonstrated functional and oncological advantages of EPR over IMN. The purpose of this study was to (1) report the durability of IMN and (2) establish the indication of IMN for femoral metastases. METHODS: In 2003-2013, among 186 surgically treated femoral metastasis cases, we retrospectively reviewed 80 consecutive IMN cases in 75 patients, including 14 pathological and 66 impending fractures. For the decision of surgical procedure (IMN, EPR, or plating), the following factors are considered: (1) fracture pattern (impending or pathological fracture), (2) Mirels' score (≥8 or <8), (3) fracture site (femoral head, neck, intertrochanter, subtrochanter, diaphysis, or distal), (4) number of metastases (solitary or multiple), and (5) patient's estimated prognosis. Patient demographics, postoperative survival, implant survival, and early postoperative mortality were reviewed. RESULTS: The patients were 37 males and 38 females, with a mean age of 60.1 (20-84) years. Average follow-up period was 11.4 (1-77) months. The most common fracture site was the subtrochanter (46/80), followed by the diaphysis (26/80) and the intertrochanter (8/80). The most common primary tumor was lung cancer (24/80, 32%), followed by breast cancer (24%) and melanoma (15%). With the exception of six cases, all patients underwent postoperative radiotherapy to the affected whole femur. The postoperative patient survival was 14.2 and 8.4% at 2 and 3 years from surgery, respectively, while the implant survival rate remained 94.0% at both 2 and 3 years. Three out of 46 subtrochanteric cases required revision surgeries because of proximal breakage of implant 4-50 months after initial surgery for femoral metastases, but all were replaced by mega-prosthesis and did not need further operation until their death. Early postoperative fatal complications were observed in three patients, all of which were pulmonary dysfunction. CONCLUSIONS: The performance of IMN in this study was satisfactory although a large portion of sub- and intertrochanter metastases were included. Broader indication including these parts should be considered, for IMN has advantages such as lower cost and less invasiveness and even an implant failure can be revised by mega-prosthetic reconstruction.

The effect of an external hip joint stabiliser on gait function after surgery for tumours located around the circumference of the pelvis: analysis of seven cases of internal hemipelvectomy or proximal femur resection.

PURPOSE: Limb-sparing resection of malignant pelvic tumours provides the opportunity for patients to obtain better post-operative mobility. However, because few studies have examined in detail the gait function of patients following pelvic tumour resection, the factors affecting gait performance remain to be clarified. Here, with the laboratory-based computer-assisted gait analysis, we evaluated these patients' gait objectively and the impact of a hip-stabilising supporter on gait improvement was simultaneously examined. METHODS: Three-dimensional gait analysis was performed to obtain cross-sectional data for seven post-operative patients (mean age, 42.7 years; range, 20-61 years) who underwent various types of resection, including P1/4 internal hemipelvectomy (IH), P1/2/3 IH, and proximal femur resection with prosthetic reconstruction. To assess the immediate effects of a hip joint stabiliser, we instructed subjects to walk at their self-selected preferred speed and compared gait parameters with and without use of the hip stabiliser. RESULTS: At baseline, the average walking speed was 0.75 m/s (95% CI 0.53-0.97). As shown by the intra-subject comparison, the hip stabiliser increased walking speed in all but one subject, increasing both temporal and spatial parameters. Ground reaction force of operated limbs increased for some subjects, while step length increased on at least one side in all subjects. CONCLUSIONS: Improvement in the gait parameters is indicative of better control provided by the external hip stabiliser over the affected limb. Moreover, our findings show the potential of a biomechanical approach to improve gait function following pelvic tumour resection.

Bilateral non-osteochondroma-related proximal tibiofibular synostosis.

We report the case of a 67-year-old male with bilateral proximal tibiofibular synostosis, presenting with unilateral symptoms. The patient complained of pain around the left fibular head, which was attributed to incomplete bone bridging between the proximal tibia and fibula; he underwent proximal fibular head resection, which alleviated the pain and improved knee mobility. Eleven months later, the patient continued to be pain-free and did not experience any adverse effects. An examination of this case and a review of similar cases revealed that participation in sport activities such as long-distance running may be one of the causes of proximal tibiofibular synostosis. In this report, we have also reconsidered the classification of proximal tibiofibular synostosis and provided information for a better understanding of this unusual condition.

Cytopathology of Chondromyxoid Fibroma: Report of 2 Cases with Immunocytochemical Expression of GRM1.

INTRODUCTION: Chondromyxoid fibroma (CMF) is a rare, benign bone tumor that occurs predominantly in the second and third decades of life, more frequently in males. Overexpression of GRM1 as a consequence of tumor-specific gene rearrangement of GRM1 has recently been reported as a useful immunohistochemical marker for histopathological diagnosis of CMF. However, the usefulness of GRM1 staining of cytology specimens has not yet been evaluated. In this report, the cytological findings and GRM1 immunocytochemistry of two cases of CMF are described. CASE PRESENTATIONS: Case 1 was a 15-year-old girl with a rib tumor. Imaging findings suggested a benign neurogenic tumor such as schwannoma. The tumor had increased in size over a 2-year period and was resected. Case 2 was a 14-year-old boy with a metatarsal tumor involving his left first toe. Imaging findings were suspicious of a benign neoplastic lesion. Biopsy findings suggested a benign tumor, and the patient underwent tumor resection. Cytologically, in both cases the tumor cells were predominantly spindle-shaped or stellate, with a myxoid to chondromyxoid background matrix and multinucleated giant cells, and these matrices were metachromatic with Giemsa staining. Cellular atypia was more accentuated in case 2 than in case 1. Immunocytochemical staining for GRM1 was positive in both cases. CONCLUSION: Due to the overlap in cytological findings, it is often difficult to differentiate CMF from chondroblastoma and chondrosarcoma grade 2. Immunocytochemical staining for GRM1 may support the diagnosis of CMF, and the reuse of Papanicolaou-stained specimens is applicable. The present cases further demonstrated the difficulty of differentiating CMF from other mimicking tumors such as chondroblastoma and chondrosarcoma grade 2. In such instances, immunocytochemistry for GRM1 is applicable to the diagnostic process, the value of which is strengthened by reusing Papanicolaou-stained specimens.

Neoadjuvant and adjuvant chemotherapy with modified mesna, adriamycin, ifosfamide, and dacarbazine (MAID) regimen for adult high-grade non-small round cell soft tissue sarcomas.

BACKGROUND: Good local control of high-grade non-small round cell soft tissue sarcomas (NSRCSTSs) has been achieved with significant advances in surgical techniques and radiotherapy. However, the role of chemotherapy remains controversial. Our aim was to investigate the efficacy, feasibility and adverse effects of neoadjuvant and adjuvant chemotherapy with modified mesna, adriamycin, ifosfamide and dacarbazine (MAID) regimen for NSRCSTSs. METHODS: We conducted a retrospective review of 40 consecutive patients (29 men, 11 women; median age 47 years) with high-grade NSRCSTSs treated in two referral centers between 2004 and 2009 (median follow-up 38.5 months). Patients with distant or nodal metastases at diagnosis were excluded. The regimen consisted of ifosfamide 2,500 mg/m(2)/6 h (days 1-3), mesna 2,500 mg/m(2)/6 h (days 1-3), tetrahydropyranyl adriamycin 20 mg/m(2)/0.5 h (days 1-3), and dacarbazine 300 mg/m(2)/1 h (days 1-3). RESULTS: Among the 26 evaluable patients, there were 8 with a partial response, 15 with stable disease, and 3 with progressive disease. Two- and 5-year overall survival rates were 92 and 86%, respectively, and corresponding disease-free survival rates were 80 and 77%. All relapses were metastases without local recurrence. Grade 3-4 neutropenia, anemia and thrombocytopenia were observed in 38, 18, and 21 patients, respectively. No serious infectious complications occurred due to the administration of granulocyte colony-stimulating factor and prophylactic antibiotics. No other life-threatening serious adverse events were observed. CONCLUSION: The modified MAID regimen achieved a better outcome with less serious adverse events than previously reported and is a potential option in the management of NSRCSTSs. Further evaluation with long-term follow-up is required.

Delirium in patients with musculoskeletal tumours: incidence and risk factors - single-centre prospective study.

OBJECTIVES: Delirium, a neurocognitive disorder, typically occurs in older patients and those with advanced cancer. Although there have been numerous reports on delirium in patients with cancer in various conditions, there are no reports that specifically focus on patients with musculoskeletal tumours. This prospective study aimed to investigate the incidence, risk factors and prognostic implications of delirium in patients with musculoskeletal tumours. METHODS: In this single institutional study, 148 patients with musculoskeletal oncology were enrolled. The estimated risk factors included age, sex, alcohol abuse, performance status (PS), dietary status, admission route, tumour malignancy, oncological stage and blood test results. The significance of delirium in survival was also examined. RESULTS: Only 18 patients with malignant tumours had delirium (12.2%). Based on univariate analysis, older age, poor PS, dietary status, admission from another hospital, malignant tumour, carcinoma rather than sarcoma, anaemia and some laboratory abnormalities were found to be significant risk factors for delirium. Multivariate analysis showed that poor PS was significantly correlated with delirium. Additionally, delirium was significantly correlated with poor survival. CONCLUSIONS: The incidence of delirium among patients with musculoskeletal tumours was 12.2% and was observed only in patients with malignant tumours. PS is a significant risk factor for delirium. Delirium is correlated with poor prognosis.

Perivascular epithelioid cell tumors (PEComas) of the bone and soft tissue: a Japanese Musculoskeletal Oncology Group (JMOG) multi-institutional study.

PURPOSE: Perivascular epithelioid cell tumors (PEComas) of the bone and soft tissues are rare mesenchymal neoplasms, some of which are malignant. However, their clinical and pathological characteristics remain unclear. This study was performed to investigate the clinical and pathological characteristics of PEComas in bone and soft tissues by leveraging information from the Japanese Musculoskeletal Oncology Group. METHODS: Nine patients, including four male and five female patients with a median age of 50 years, were retrospectively reviewed. PEComas of the visceral organs, including the uterus and retroperitoneum, were excluded. RESULTS: Eight tumors arose in the soft tissue and one in the bone, with a mean size of 8.8 cm. Four patients showed local recurrence or distant metastasis. The 1-year survival rate was 78%. Pathologically, eight tumors were classified as malignant and one as having uncertain malignancy potential. Half of the tumors showed high MIB-1 index values of > 30%. Immunohistochemically, the melanocyte marker HMB45 was expressed in 89% of the cases, and muscle-specific markers were expressed only in 30-50% of the cases. Transcription factor binding to IGHM enhancer 3 (TFE3) expression was positive in 100% of the patients. Tumors with high expression of TFE3 were classified as PEComas with malignant potential according to Folpe's classification. CONCLUSIONS: Bone and soft tissue PEComas may have a higher malignancy potential than other visceral PEComas and are more likely to develop as TFE3-rearranged PEComas.

Rare Case of BCOR::CCNB3 Sarcoma of Bone.

BACKGROUND BCOR: CCNB3 sarcoma is a rare mesenchymal tumor that was formerly included in the undifferentiated/unclassified sarcoma group and was recently reclassified as one of undifferentiated small round cell sarcomas with a genetically distinct subtype in the WHO 2020 classification. Because of its rarity, still not much is known, especially about its clinical features. CASE REPORT A 15-year-old boy presented with almost 1-year intermittent thigh pain. On the first visit, a pathologic fracture of the femur and a big mass expanding through the femoral cortex with lobular shape and homogenous appearance were recognized on radiography and magnetic resonance imaging. Plain radiography, which was taken 6 months before at a local clinic, showed an expansion and thickening of the right proximal femoral shaft. Biopsy specimen of the lesion revealed a proliferation of round to spindle tumor cells with diffuse and strong immunohistochemical nuclear positivity for BCOR and CCNB3. Under the diagnosis of BCOR::CCNB3 sarcoma of the femur, a chemotherapy based on a protocol of Ewing sarcoma, followed by a wide resection and total femoral replacement surgery, were conducted. The effect of chemotherapy was favorable, showing no microscopic residual tumor. Although postoperative chemotherapy was not completed because of a minor infection detected on the surgical site, the patient was doing well, without any recurrence, for 26 months. CONCLUSIONS BCOR: CCNB3 sarcoma of the bone is a quite rare tumor with much lower incidence than Ewing sarcoma. Notable clinical characteristics of the current case were a 1-year-long symptomatic period and homogenous appearance on MRI.