PRRX1-TOP2A interaction is a malignancy-promoting factor in human malignant peripheral nerve sheath tumours

BACKGROUND

Paired related-homeobox 1 (PRRX1) is a transcription factor in the regulation of developmental morphogenetic processes. There is growing evidence that PRRX1 is highly expressed in certain cancers and is critically involved in human survival prognosis. However, the molecular mechanism of PRRX1 in cancer malignancy remains to be elucidated.

METHODS

PRRX1 expression in human Malignant peripheral nerve sheath tumours (MPNSTs) samples was detected immunohistochemically to evaluate survival prognosis. MPNST models with PRRX1 gene knockdown or overexpression were constructed in vitro and the phenotype of MPNST cells was evaluated. Bioinformatics analysis combined with co-immunoprecipitation, mass spectrometry, RNA-seq and structural prediction were used to identify proteins interacting with PRRX1.

RESULTS

High expression of PRRX1 was associated with a poor prognosis for MPNST. PRRX1 knockdown suppressed the tumorigenic potential. PRRX1 overexpressed in MPNSTs directly interacts with topoisomerase 2 A (TOP2A) to cooperatively promote epithelial-mesenchymal transition and increase expression of tumour malignancy-related gene sets including mTORC1, KRAS and SRC signalling pathways. Etoposide, a TOP2A inhibitor used in the treatment of MPNST, may exhibit one of its anticancer effects by inhibiting the PRRX1-TOP2A interaction.

CONCLUSION

Targeting the PRRX1-TOP2A interaction in malignant tumours with high PRRX1 expression might provide a novel tumour-selective therapeutic strategy.

Walking ability after resection of soft tissue sarcoma of the thigh and the sciatic nerve

Walking ability may be fairly well maintained after sciatic nerve resection combined with wide resection of soft tissue sarcoma, therefore, surgeons should not hesitate to perform sciatic nerve resection to achieve an adequate surgical margin.

Rib stress fracture in a female athlete caused by bouncing the barbell in bench press exercise: A case report

Rib stress fractures can occur in sports involving repetitive trunk muscle contractions. Few documented cases show rib fractures from repetitive upper-limb training. This report presents a case of a rib stress fracture from micro blunt trauma during bench press exercises. The patient was a 24-year-old elite female sprinter with a history of left navicular stress fracture and secondary amenorrhea treatment a year prior. She modified her bench press technique to involve bouncing the barbell on her rib cage. Within weeks, she experienced anterior chest pain, exacerbated by sneezing. Computed tomography revealed a fifth rib fracture with callus formation. After refraining from bench presses for 4 weeks, her chest pain subsided, allowing her to resume upper-limb training. When athletes performing bench press exercises experience chest pain, rib fractures should be considered, even without acute trauma. Additionally, research on the safety of the bouncing bench pressing technique is required.

Reference values of lumbar spine range of motion by sex and age based on the assessment of supine trunk lateral bending-A preliminary study

[Purpose] The purpose of this study was to clarify the preliminary reference values for the lumbar spine range of motion associated with lateral bending exercises by gender and age group. [Methods] Subjects were 82 volunteers without low back pain, including five males and five females in each age group from 16-19 to 80-89 years. All subjects underwent radiographs of the lumbar spine with lateral flexion; the range of lateral flexion of the vertebrae from T12 to the sacrum (ROLB) was measured twice by three observers. [Results] The ROLB of the entire T12-S1 of all subjects showed a significant negative correlation with age in both sexes (p < 0.01). The ROLB of the lumbar spine tended to be greater in females, with a statistically significant difference between those aged 16-19 and 70-79 (p < 0.05). Lateral flexion angles for each intervertebral segment were largest at L3-L4 and smallest at L5-S1 (0.7°). [Conclusion] Lumbar ROLB reference values were examined by gender and age group; ROLB was greatest in L3-L4, and ROLB tended to be lower in older age groups.

Knee locking caused by osteochondroma of the proximal tibia adjacent to the pes anserinus: A case report

BACKGROUND

Osteochondroma is one of the most common benign bone tumors, and it may cause bone and joint deformities and limited range of motion of an adjacent joint. The pes anserinus region is one of the most frequent sites of osteochondroma, but knee locking caused by osteochondromas in the pes anserinus region is extremely rare.

CASE SUMMARY

We describe a 13-year-old Japanese girl's extra-articular knee locking that occurred when the semitendinosus tendon got caught in osteochondroma that had developed in the pes anserinus region. The osteochondroma was surgically resected. The postoperative outcome has been excellent, with no recurrence of knee locking or tumor one-year post-surgery.

CONCLUSION

When a young person develops knee locking, the possibility of extra-articular as well as intra-articular locking should be considered. Osteochondroma, one of the causes of extra-articular locking, can be treated with surgery with good postoperative results.

Radiological and pathological characteristics of synovial hemangioma of the knee

Synovial hemangioma, a rare benign tumor that occurs most frequently in the knee in children and young adults, has four histological subtypes: Venous, arteriovenous, cavernous and capillary hemangiomas. Since the clinical presentation and radiological findings of synovial hemangioma are non-specific, there is frequently a long period between the onset and the diagnosis. The cases of nine patients, pathologically diagnosed with synovial hemangioma and surgically treated, were retrospectively analyzed. All nine patients had persistent knee pain. In addition, three patients also had a swollen knee with intra-articular hemorrhage. Plain radiography revealed intra-articular phleboliths in two patients. In seven patients, T1-weighted magnetic resonance imaging showed low signal intensity with small signal voids. On T2-weighted imaging, all patients showed high signal intensity containing small signal voids. All patients underwent surgical excision; there was no postoperative recurrence after the final operation, and the knee pain had disappeared at the final follow-up. From the pathological findings, the diagnoses were venous hemangioma, cavernous hemangioma and capillary hemangioma (three patients each).

Fibulo-Scapho-Lunate Arthrodesis With Free Vascularized Fibular Graft for a Japanese Kyudo Archer With Osteosarcoma of the Left Distal Radius: A Case Report

BACKGROUND

Recent progress in the chemotherapy and surgical procedures for osteosarcoma have enabled the preservation of limb function even when cancer occurs in the distal radius, a rare primary site of osteosarcoma.

CASE REPORT

We describe a case of osteosarcoma that occurred in an 18-year-old, male Kyudo (Japanese archery) archer's left distal radius. Since the patient desired to resume Kyudo and the left hand was quite important for gripping a bow, we chose partial wrist arthrodesis (fibulo-scapho-lunate arthrodesis) with free vascularized fibular grafting (FVFG) as the reconstruction procedure following wide resection. After the wide resection, the major axis of bone defect was 8 cm. We harvested a free vascularized fibular graft with fascio-cutaneous flap with wide fascia to reconstruct the gliding surface of the extensor tendon. Fibula-proximal radius and fibulo-scapho-lunate fixation was performed by locking plates individually. Vascular anastomosis was performed between the radial artery and peroneal artery in a flow-through manner. Two peroneal veins were anastomosed with the radial vein and cephalic vein.

CONCLUSION

Fibulo-scapho-lunate arthrodesis with FVFG may provide satisfied stability and function even in a Kyudo archer. The patient obtained sufficient wrist stability and grip strength, and could resume Kyudo.

Surgical treatment for a combined anterior cruciate ligament and posterior cruciate ligament avulsion fracture: A case report

BACKGROUND

Independent avulsion fractures with anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) attachment are relatively common among tibial intercondylar eminence fractures, and their postoperative outcomes are generally favorable. Conversely, huge avulsion fractures of the intercondylar eminence containing the attachment site of both the ACL and the PCL are extremely rare, and the reported clinical outcomes are poor.

CASE SUMMARY

We describe a 30-year-old Japanese male's huge avulsion fracture of the intercondylar eminence of a tibia containing the attachment site of both the ACL and PCL, together with a complete tear of the medial collateral ligament and a partial tear of both the medial and lateral menisci caused by a fall from a high place. All of these injuries were treated surgically, with anatomical reduction and stable fixation. The limb function at 1 year post-surgery was excellent (Lysholm score: 100 points).

CONCLUSION

Although this patient's complete surgical repair was complex, it should be performed in similar cases for an excellent final clinical outcome.

Progressive enlargement of thoracic ossification of the ligamentum flavum in professional baseball pitchers: a report of two cases

Both systemic and local factors might influence the development of ossification of the ligamentum flavum (OLF); however, whether specific physical activities play a role in the development of OLF remains unclear. This report presents two cases of thoracic radiculopathy owing to progressive enlargement of thoracic OLF within a few years in Japanese professional baseball pitchers. Two left-handed, Japanese, professional baseball pitchers in their 20s experienced thoracic radiating pain. Mild hypesthesia of the lower thoracic vertebral levels was observed, and an increase in the size of the OLF within a few years was identified in the lower thoracic spine using computed tomography and magnetic resonance imaging. Neither patient exhibited myelopathy and were, therefore, treated conservatively. Both patients were able to return to playing in top condition within 4 months after onset. The findings in these cases suggest that thoracic OLF might increase in size and become exacerbated in certain individuals, such as professional pitchers, who experience repeated, localized, mechanical stress on the thoracic spine, irrespective of age.

Talipes Equinus Deformity Caused by Fibrous Gastrocnemius Muscle Contracture After Direct Contusion in Football Players: Report of Two Cases

Two main causes of gastrocnemius contracture have been considered: 1) congenital deformities in pediatric patients, such as limb-length discrepancy, cerebral palsy, flatfoot, and clubfoot; and 2) secondary conditions such as immobilization for trauma or a nonfunctional limb. Talipes equinus deformity caused by fibrous gastrocnemius contracture after a direct muscle contusion is extremely rare. We describe 2 cases of talipes equinus deformity caused by fibrous gastrocnemius muscle contracture after a direct contusion in football players. Both of the players had a talipes equinus deformity with a severe restriction of ankle dorsiflexion, and a cord-like structure was observed at the proximal part of the lateral gastrocnemius head. Both patients' histological examinations revealed fibrous tendon-like tissue within the structure. After discission of the cord-like structures, the restriction of ankle dorsiflexion was completely resolved, and the patients were able to fully return to playing football without any discomfort in their calves.

Periprosthetic Fracture Resembling Atypical Femoral Fracture After Fixation With Retrograde Intramedullary Nail in Elderly Women: A Report of Two Cases

BACKGROUND/AIM

The number of individuals diagnosed with and requiring medical treatment for osteoporosis continues to increase due to global population aging and the high awareness of osteoporosis. Bone-modifying agents (BMAs) including bisphosphonate and denosumab are widely used for osteoporosis, and atypical femoral fracture (AFF) is also gaining attention as a severe potential side effect of long-term BMA treatment. The definition of AFF excludes periprosthetic femoral fracture; here, we describe two cases of a periprosthetic femoral fracture that resembled AFF.

CASE REPORT

The fractures occurred at the proximal tip of the retrograde femoral nail after an internal fixation for a distal femoral shaft fracture in elderly Japanese women. Each woman had been treated with bisphosphonate therapy for >2 years and had continued the bisphosphonate after undergoing surgery for a distal femoral shaft fracture. Each patient had noticed thigh pain before falling down, and plain radiographs showed a short oblique or transverse fracture with medial spike and localized periosteal reaction of the lateral cortex in each case. The fractures were re-fixed with an antegrade intramedullary nail, and bone union was achieved at >1 year after the second operation. Although these two cases were classified as periprosthetic fractures, they fulfilled the characteristics of AFF.

CONCLUSION

Physicians should conduct a thorough interview of patients with a history of BMA treatment in order to correctly diagnose periprosthetic fractures that resemble AFFs, and they should be aware that symptomatic fractures can be prevented by prophylactic fixation. The discontinuance of BMA therapy and the introduction of another drug such as teriparatide may lead to faster healing of surgically treated AFFs.

Familial development of lumbar spondylolysis: a familial case report of 7- and 4-year-old brothers and their father

The incidence of lumbar spondylolysis is affected by sex, race, and congenital abnormalities. These differences suggest a genetic component to the etiology of spondylolysis. However, no definitive evidence has been presented regarding the inheritance of lumbar spondylolysis. We report familial cases of lumbar spondylolysis in 7- and 4-year-old brothers and their father, each of whom visited our clinic complaining of low back pain. Spondylolysis in the fifth lumbar vertebra (L5) was identified in both boys and their father from clinical, radiographic, computed tomographic, and magnetic resonance imaging examinations. Conservative treatment was provided for both boys. No bony union of any spondylolytic lesions was obtained, but they returned to sports activity without low back pain. Frequent development of spondylolysis, even at younger ages, in all male family members might indicate an underlying genetic etiology in lumbar spondylolysis, primarily in the form of autosomal dominant inheritance. However, information on patients and their parents should be considered carefully, as bony union with conservative therapy is not expected in such patients.

Salvage Reconstruction With the Masquelet Technique Following Wide Resection for Chondrosarcoma of the Proximal Femoral Metaphysis: A Case Report

BACKGROUND

Bone reconstruction following a wide resection for a malignant musculoskeletal tumor remains challenging, especially for an intercalary defect following the resection of a metaphyseal lesion.

CASE REPORT

Here, we describe a surgical procedure using the Masquelet technique for the biological reconstruction of a huge subtrochanteric bone defect following failed pasteurized autologous bone grafting for a conventional chondrosarcoma of the proximal femoral metaphysis with a subtrochanteric pathological fracture. The patient, a 43-year-old Japanese male, was able to walk without a cane or a brace at 15 months after the final operation (International Society of Limb Salvage score, 86.7%).

CONCLUSION

This procedure should be considered as one of the reconstruction options following the wide resection of malignant bone tumors located in the metaphysis.

Very late relapse of high-grade osteosarcoma: A case report and review of the literature

RATIONALE

Osteosarcoma is the most common primary malignant bone tumor in children. The prognosis of osteosarcoma has improved with the use of aggressive systemic chemotherapy in addition to surgery. The relapse of osteosarcomas is usually as lung metastasis observed within 2 to 3 years after the initial treatment. A relapse is rarely observed at >10 years.

PATIENT CONCERNS

We report the case of a 51-year-old Japanese man who was treated for high-grade osteosarcoma of the femur at 13 years old. He was referred to our hospital with a suspicion of primary lung cancer based on back pain, respiratory distress, and an abnormal mass on chest radiograph.

DIAGNOSES

Computed tomography-guided biopsy confirmed the lung lesion as a metastatic recurrence of high-grade osteosarcoma without local recurrence.

INTERVENTIONS

Chemotherapy was planned, but the patient's general condition rapidly deteriorated and thus palliative therapy was provided.

OUTCOMES

The patient died 2 months after the initial consultation.

LESSONS

The survival durations of osteosarcoma patients have been prolonged by recent progress in multimodality therapy, and thus clinicians as well as osteosarcoma patients should always keep in mind the possibility of very late relapse.

Impaired Extension of the Digits due to Bilateral Idiopathic Intrinsic Contracture: A Case Report

Idiopathic intrinsic contracture (IIC) with no history of trauma, ischemia, or spasticity is extremely rare. We report herein a case of impaired extension of the digits due to bilateral IICs occurred in a 30-year-old woman with a past medical history of eating disorder and amenorrhea. Although no previous case has been reported in the literature, eight similar cases of IIC have been presented at Japanese domestic conferences. In these eight cases and the present case, resection of the thenar muscle cords and unilateral resection of the lateral band were effective. Since IIC in patients with an eating disorder is a rare condition, it would be treated conservatively at first as tendon sheath inflammation or locking. However, this condition may be resistant to conservative treatment, and surgical treatment should be considered in such cases.

Total knee arthroplasty in Japanese patients aged 80 years or older

Objective

The population of Japan is aging rapidly, and, since the aging of patients who undergo total knee arthroplasty (TKA) is also expected, it is necessary to determine the efficacy and safety of TKA among old adult patients.

Methods

This study retrospectively analyzed the cases of patients who underwent a primary TKA for osteoarthritis at Bange Kosei General Hospital between January 2009 and June 2014 and were postoperatively followed-up for ≥1 year. Among the 2,945 knees of the 1,968 patients, 1,003 knees of 679 patients aged ≥80 years at the time of surgery were designated as the older group, and we compared their cases with those of the younger group of 1,044 knees of 673 patients aged <75 years.

Results

The rates of improvement of the Japanese Orthopaedic Association (JOA) score were not significantly different between the older and younger groups. Postoperative ranges of motion were significantly improved in both groups. The number of postoperative days of hospital stay in the older group was 2 days longer than that of the younger group. Concerning postoperative complications, confusion, delayed wound healing, and acute heart failure were significantly more frequent in the older group. The frequencies of pneumonia, cerebral infarction, peroneal nerve palsy, and bedsore did not differ significantly. Loosening of implants was observed: older group, n=0 joints; younger group, n=5 joints. The number of prosthetic joint infections: older group, n=5; younger group, n=2 (non-significant).

Conclusion

The rate of improvement in the JOA score did not differ significantly between the groups. TKA is an effective and safe treatment for osteoarthritis, even in old adult patients, when the surgical indication is based on careful preoperative screening and attention to specific postoperative complications.

Various checkpoint molecules, and tumor-infiltrating lymphocytes in common pediatric solid tumors: Possibilities for novel immunotherapy

Long-term survival rates for pediatric patients with cancer have significantly improved, but novel approaches are desired for those with refractory/relapsed solid tumors. Recently, programed cell death-1/programed cell death-ligand-1 blockade has emerged as an effective option for many intractable cancers. However, not all patients show objective response to such therapy. On the other hand, several other checkpoint pathways, including Herpes virus entry mediator (HVEM)/B- and T-lymphocyte attenuator (BTLA), galectin-9 (GAL9)/T-cell immunoglobulin and mucin domain-3 (TIM3), and major histocompatibility complex class II (MHC-II)/lymphocyte activation gene-3 (LAG3), also regulate immune responses in the tumor microenvironment and may be alternative targets for novel immune therapies. In this study, we examined 65 common pediatric solid tumors and characterized the expression of Herpes virus entry mediator, GAL9, and MHC-II on tumor cells and their corresponding receptors B- and T-lymphocyte attenuator, TIM3, and LAG3, respectively, on tumor-infiltrating lymphocytes (TILs) with immunohistochemistry. Whereas the expression of GAL9 and MHC-II was limited, 73% of rhabdomyosarcomas and 100% of osteosarcomas expressed moderate to high levels of Herpes virus entry mediator on the tumor. TILs were detected in all tumor samples except one osteosarcoma. Interestingly, 45% of rhabdomyosarcomas, and 45% of osteosarcomas expressed moderate to high levels of both Herpes virus entry mediator on the tumor cells and B- and T-lymphocyte attenuator on the TILs. Results showed that a subset of pediatric solid tumors expressed tumor-associated checkpoint molecules, and TILs expressed corresponding receptors for these checkpoint molecules. Thus, immunogenic environments may be created, and checkpoint blockade may induce favorable immune responses.

Establishment and Characterization of a Novel Human Clear-cell Sarcoma of Soft-tissue Cell Line, RSAR001, Derived from Pleural Effusion of a Patient with Pleural Dissemination

BACKGROUND/AIM

Clear cell sarcoma (CCS) of soft tissue is exceedingly rare and frequently exhibits aggressive behavior. Toward the goals of improving the aggressive course and poor prognosis of CCS, and establish new therapeutic methods, molecular genetic and biological characterizations of CCS are required.

MATERIALS AND METHODS

A new human CCS cell line (designated RSAR001) was established from the pleural effusion of a 44-year-old man with multiple lung metastases and pleural dissemination. The cell line and its xenograft were characterized including their morphology, immunohistochemistry, cytogenetic analysis, reverse transcription-polymerase chain reaction, direct sequencing analysis, and fluorescence in situ hybridization analysis.

RESULTS

The cell line has been maintained for over 12 months with more than 50 passages. RSAR001 cells exhibited a fascicular or diffuse growth pattern of short spindle- or oval-shaped cells with clear cytoplasm in heterotransplanted tumor, that was similar to the primary tumor. Immunophenotypically, RSAR001 cells in vitro and in vivo exhibited almost the same characteristics as the primary tumor. Cytogenetic analyses revealed a translocation, t(12;22)(q13;q12). Reverse transcription-polymerase chain reaction and direct sequencing analysis detected transcripts of the Ewing sarcoma breakpoint region 1-activating transcription factor 1 (EWSR1-ATF1) type 1 fusion gene. Fluorescence in situ hybridization using a break-apart probe for the EWSR1 gene on 22q12 showed a rearrangement.

CONCLUSION

These findings indicate that the RSAR001 cell line harbors EWSR1-ATF1 type 1 chimeric fusion gene, which is specific to CCS. RSAR001 cells might be useful for investigating biological behaviors and developing new treatments such as molecular-targeting antitumor drugs or immunological drugs for CCS.

Bony Maturity of the Tibial Tuberosity With Regard to Age and Sex and Its Relationship to Pathogenesis of Osgood-Schlatter Disease: An Ultrasonographic Study

BACKGROUND

Although tensile force on an immature tibial tuberosity is considered the main cause of Osgood-Schlatter disease (OSD), the relationship between bony maturity and the pathogenesis of OSD remains obscure.

PURPOSE

To survey the bone maturation process of the tibial tuberosity by age and sex and clarify its relationship to OSD.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 731 Japanese basketball players aged 6 to 14 years were enrolled in this study. Ultrasonographic examination was performed in all participants (1462 knees) to evaluate the bony maturity of the tibial tuberosity by use of the Ehrenborg classification. The age- and sex-specific prevalence of each stage was investigated, and the prevalence of symptomatic OSD and its relationship with bony maturity were also assessed.

RESULTS

The process of bone maturation occurred 1 to 2 years earlier in female participants compared with male participants. Among female participants, 59.2% were already at the epiphyseal stage (stage E) by 10 years of age, and 47.4% were skeletally mature by 14 years. Among male participants, conversely, only 8.0% were at stage E by 10 years of age, and only 13.8% were skeletally mature by 14 years. The overall prevalence of symptomatic OSD was 6.8% (males, 6.4%; females, 7.2%), and the onset was 1 year earlier in the female participants. The prevalence of symptomatic OSD tended to increase with age and bony maturity, significantly increasing from the cartilaginous stage (stage C) to the apophyseal stage (stage A) (odds ratio, 9.48) and from stage A to stage E (odds ratio, 2.22).

CONCLUSION

The tibial tuberosity matures earlier in female participants. The risk of OSD is greater in stage A than stage C and in stage E than stage A. The risk of OSD increases with age in males but not in females.

Primary malignant lymphoma of the talus: A case report and review of the literature

Malignant lymphoma commonly occurs in adults, with a peak incidence between the seventh and ninth decades of life. Although malignant lymphoma usually occurs in the lymph nodes, it rarely occurs primarily in the bone. We herein describe an extremely rare case of primary malignant lymphoma of the talus in a 74-year-old man. Although plain radiographs showed no abnormality, gadolinium-enhanced magnetic resonance imaging (MRI) revealed a well-circumscribed intra- and extraosseous tumor of the talus. ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/MRI revealed a marked increase of FDG uptake in the right ankle and the right inguinal lymph nodes. As the tumor was diagnosed as diffuse large B-cell lymphoma by core needle biopsy, combination therapy with chemo- and radiotherapy was initiated. The patient achieved complete remission, with no sign of recurrence at 8 months after initial chemoradiotherapy. Since primary malignant lymphoma of the bone is chemo- and radiosensitive and has a good prognosis, accurate staging by radiological investigation as well as correct pathological diagnosis by biopsy are required for optimal treatment.

Prolonged infection at the tibial bone tunnel after anterior cruciate ligament reconstruction

A 24-year-old man with severe atopic dermatitis underwent anterior cruciate ligament (ACL) reconstruction of the right knee seven years earlier but developed a surgical site infection. The infection did not heal after removal of the metal implants, and a fistula eventually developed. This condition was left untreated for six years before he was referred to our hospital. Magnetic resonance imaging showed fluid in the tibial bone tunnel and extensive bone marrow edema surrounding the bone tunnel. Based on these findings, abscess formation within the tibial bone tunnel and osteomyelitis spreading to the proximal tibia were suspected. During the surgery, a portion of artificial ligament and non-absorbable suture were observed in the bone tunnel, and the infection healed immediately after removal of this complex. When surgical site infection occurs after ACL reconstruction, it is important to completely remove all artificial materials as early as possible.

Osteochondroma of the Tibial Sesamoid: A Case Report and Review of the Literature

Osteochondroma, one of the most common benign bone tumors, frequently occurs in the metaphysis of the long bones. We report an extremely rare case of osteochondroma that occurred in the tibial sesamoid. The patient was a 62-year-old Japanese male. He presented with a 1-year history of pain and a hard mass on the plantar aspect of the right forefoot sole. The osteochondroma protruded toward the sole from the tibial sesamoid, leading to pain on weightbearing. After tibial sesamoidectomy, the patient's symptoms were eliminated, and no pain or complications such as hallux valgus occurred after the surgery. Although a potential risk exists of postoperative hallux valgus deformity, tibial sesamoidectomy seems to be an appropriate surgical option for both osteochondroma and bizarre parosteal osteochondromatous proliferation to avoid residual pain or local recurrence.

Surgical anatomy of the pelvic vasculature, with particular reference to acetabular screw fixation in cementless total hip arthroplasty in Asian population

PURPOSE

Pelvic vascular injury is a serious complication associated with acetabular component setting with screw fixation in cementless total hip arthroplasty (THA). In this study, we investigated the safety zone for acetabular component setting with screw fixation in cementless THA as a means to prevent pelvic vascular injury.

METHODS

Thirty left hip joints of Japanese cadavers (11 males and 19 females) were analyzed. We used a hemispherical measuring cup with 52 guide holes designed to allow vertical insertion of a Kirschner wire. After the measuring cup was placed on the acetabulum, the Kirschner wire was inserted from each guide hole to examine the anatomical relationship between the acetabulum and the pelvic vessels. We calculated the frequency of pelvic vessel punctures and measured the distance from the acetabular surface to the pelvic vessels at each guide hole.

RESULTS

Our findings revealed that pelvic vessels do not exist in certain parts of the posterior area of the acetabulum. Furthermore, in this area, intrapelvic vessels are either lacking or located at a distance ≥31 mm from the surface of the acetabulum.

CONCLUSION

The posterior area of the acetabulum, excluding its central portion, appeared to be the safety zone for acetabular screw fixation in Japanese cadavers.

Surgical treatment options for septic non-union of the tibia: two staged operation, Flow-through anastomosis of FVFG, and continuous local intraarterial infusion of heparin

BACKGROUND

The treatment of septic non-union of the tibia is a challenging area.　The objective of this clinical study was to improve the treatment outcomes in patients with a highly active infection by the three strategies consisting of a two-staged operation, a flow-through technique for vascular anastomosis of a free vascularized fibular graft (FVFG), and continuous local intra-arterial infusion of heparin.

PATIENTS & METHOD

Five patients with septic non-union of the tibia who were treated with an FVFG (mean age: 52.8 years) were enrolled.　The mean postoperative follow-up period was 47.2 months, and the mean length of the bone defect was 111 mm.　A two-staged operation, in which polymethylmethacrylate (PMMA) beads containing antibiotics were inserted into a bone defect followed by bone reconstruction performed with an FVFG later.　Vascular anastomosis was performed with the flow-through technique in all patients.　Immediately after FVFG, heparin was continuously infused through a femoral arterial catheter for 1 week.

RESULT

Bone union was confirmed an average of 18.8 weeks after-surgery in all patients without reoperation for thrombus.

CONCLUSION

Our attempt to apply the strategies appears to be a viable treatment option for septic non-union of the tibia.

Missed causative tumors in diagnosing tumor-induced osteomalacia with (18)F-FDG PET/CT: a potential pitfall of standard-field imaging

OBJECTIVE

We describe herein two tumor-induced osteomalacia (TIO) cases for whom the causative lesions, located in their popliteal fossa, that were not identified in the standard field of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT), which usually images only the head, trunk, and proximal parts of the extremities.

CLINICAL PRESENTATION AND INTERVENTION

A 47 years old Japanese man with multiple pathological fractures due to osteomalacia, accompanied by muscle weakness, hypophosphatemia, and an elevation of alkaline phosphatase (ALP) was referred to our hospital. A (18)F-FDG PET/CT scan was performed, but no (18)F-FDG uptake was detected in the standard field of imaging. Magnetic resonance imaging revealed a small subcutaneous tumor (1.9×1.2×0.6cm) of the left posteriomedial knee, displaying uniform enhancement on gadolinium-enhanced T1-weighted fat-suppression imaging. The tumor was resected widely and diagnosed as phosphaturic mesenchymal tumor, mixed connective tissue variant (PMTMCT). The other patient was a 31 years old Japanese woman with multiple pathological fractures, hypophosphatemia and elevated of ALP and was referred to our hospital on suspicion of TIO. Although the causative lesion was not identified in the standard field of (18)F-FDG PET/CT, (18)F-FDG uptake (SUVmax 2.9) was detected on the right knee in the additional whole-body (18)F-FDG PET/CT. Magnetic resonance imaging revealed a soft-tissue tumor (6.4×4.1×2.9cm) in the right posterior knee. Following biopsy, the tumor was marginally resected, and was pathologically diagnosed as PMTMCT.

CONCLUSION

Once patients are suspected to have TIO, a whole-body nuclear imaging study such as (18)F-FDG PET/CT should be performed, in order not to miss the hidden causative tumor, especially occurring in the distal extremities.

Primary dumbbell-shaped epidural myxoid liposarcoma of the thoracic spine: A case report and review of the literature

Myxoid liposarcoma frequently occurs in the deep soft tissue of the extremities, particularly in the thigh. The present study describes an extremely rare case of primary dumbbell-shaped epidural myxoid liposarcoma of the thoracic spine occurring in a 22-year-old woman. Although preoperative magnetic resonance imaging findings were thought to be compatible with schwannoma, the pathological diagnosis of the resected tumor was myxoid liposarcoma. The patient underwent three courses of adjuvant chemotherapy with doxorubicin and ifosfamide, and exhibited no symptoms or signs of local recurrence or metastasis for 18 months post surgery. The present case suggests that, when radiologically diagnosing spinal epidural tumors, clinicians should consider the possibility of myxoid liposarcoma.

Gorham's disease of the proximal tibia successfully treated with local administration of OK-432, followed by reconstruction with distraction osteogenesis: a case report

Gorham's disease (GD) is a rare and intractable disease characterized by marked progression of osteolysis associated with lymphangioma and/or hemangioma. Here, we describe a case of GD of the proximal tibia occurring in a 10-year-old boy. Although we could not correctly diagnose it at first, we finally diagnosed him as having GD. Progression of osteolysis of the tibia stopped 3 months after the local administration of OK-432. Thereafter, the huge bone defect with varus and extension deformity was reconstructed successfully by distraction osteogenesis using the Ilizarov method. The present case suggests that local administration of OK-432, followed by distraction osteogenesis is a treatment option for GD.

Elevated expression of HSP90 and the antitumor effect of an HSP90 inhibitor via inactivation of the Akt/mTOR pathway in undifferentiated pleomorphic sarcoma

BACKGROUND

Undifferentiated pleomorphic sarcoma (UPS) is a heterogeneous tumor group, and little is known about molecular target therapy for UPS. Heat shock protein 90 (HSP90) is an expressed chaperone that refolds certain denatured proteins under stress conditions. One of these proteins is Akt. The disruption of Akt signaling plays an important role in tumor progression. The present study's purpose was to analyze the HSP90 expression, Akt/mTOR pathway activation and the correlation between HSP90 expression and its pathway activation in UPS.

METHODS

The status of HSP90 and the profiles of the Akt/ mTOR pathway were assessed by immunohistochemistry in 79 samples of UPS, and these data were compared with clinicopathological and histopathological findings. The expressions of indicated proteins were assessed by Western blotting in five frozen samples. After treating UPS cells with the HSP90 inhibitor, we assessed the antitumor effect of the inhibitor.

RESULTS

Immunohistochemically, phosphorylated Akt (p-Akt), p-mTOR, p-S6RP and p-4EBP were positive in 57.3, 51.9, 54.5 and 57.1% of the UPS samples, respectively. The expressions of those phosphorylated proteins were correlated with each other. HSP90 expression was elevated in 56.4% of the samples and was correlated with p-Akt, p-mTOR and p-S6RP. The immunohistochemical results were confirmed by Western blotting. The HSP90 inhibitor led to decreased viability and invasiveness of the cells and inactivated the AKT/mTOR pathway in vitro.

CONCLUSION

Elevated expression of HSP90 is a poor-prognosis factor and is involved in the activation of the Akt/mTOR pathway in UPS. HSP90 inhibition is a potential treatment option for UPS.

Functional reconstruction of the knee extension mechanism following wide resection for a prepatellar soft-tissue sarcoma: A case report

Functional reconstruction following a wide resection for a malignant musculoskeletal tumor is often challenging, particularly for juxta-articular tumors. The current study describes a novel surgical procedure for the functional reconstruction of the knee extensor mechanism with a pedicle frozen auto-bone and -tendon graft, in a case of prepatellar clear cell sarcoma. The active range of motion of the knee was from 0-135°, and the extension muscular strength of the knee was evaluated as 5/5 by a manual muscle test at 14 months post-surgery (International Society of Limb Salvage score, 73%); this was improved compared with a similar procedure previously described by Muramatsu et al. This procedure must be considered following the wide resection of juxta-articular malignant musculoskeletal tumors.

LONG-TERM FOLLOW-UP OF FREE VASCULARIZED FIBULAR HEAD GRAFT FOR RECONSTRUCTION OF THE PROXIMAL HUMERUS AFTER WIDE RESECTION FOR BONE SARCOMA

PURPOSE

This study investigated the shape of bone grafts and associations with upper limb function over the long term after free vascularized fibular head graft (FVFHG) for reconstruction of the proximal humerus after wide resection for bone sarcoma.

METHODS

Patients comprised 3 women who had undergone FVFHG at least 5 years previously. Age at surgery was 12 years in 2 cases and 76 years in one. The mean follow-up periods were 10 years 4 months. Evaluated parameters comprised: 1) graft hypertrophy, and 2) shape of the fibular head as changes in shape of the bone graft; and 3) ISOLS score, and 4) DASH score as indicators of upper limb function.

RESULTS

Rates of graft hypertrophy of the fibular shaft were -14%, -17%, and -20%, respectively, with transverse diameter decreasing in all cases. In terms of changes in shape of the grafted fibular head, transverse diameter had diminished in 2 patients (-5 mm and -2 mm), and the head had been completely resorbed in the remaining patient. Both patients in whom the fibular head remained were young, and both had good ISOLS scores >80% and good DASH scores of 5.0 and 8.3. The patient in whom the fibular head had been resorbed was elderly, with ISOLS and DASH scores of 73.3% and 34.2, respectively; comparatively poor compared with the other two. A comparison of ISOLS and DASH scores before and after fibular head resorption, however, showed no deterioration in either score.

CONCLUSIONS

Long-term follow-up of humerus reconstruction by FVFHG showed no deterioration in upper limb function despite the risk of fibular head resorption. FVFHG of the proximal humerus is a reconstruction technique that can provide good long-term upper limb function.

Expression and regulation of toll-like receptors (TLRs) in human intervertebral disc cells

PURPOSE

Although inflammatory processes play an essential role in painful intervertebral disc (IVD) degeneration, the underlying regulatory mechanisms are not well understood. This study was designed to investigate the expression, regulation and importance of specific toll-like receptors (TLRs)--which have been shown to play an essential role e.g. in osteoarthritis--during degenerative disc disease.

METHODS

The expression of TLRs in human IVDs was measured in isolated cells as well as in normal or degenerated IVD tissue. The role of IL-1β or TNF-α in regulating TLRs (expression/activation) as well as in regulating activity of down-stream pathways (NF-κB) and expression of inflammation-related genes (IL-6, IL-8, HSP60, HSP70, HMGB1) was analyzed.

RESULTS

Expression of TLR1/2/3/4/5/6/9/10 was detected in isolated human IVD cells, with TLR1/2/4/6 being dependent on the degree of IVD degeneration. Stimulation with IL-1β or TNF-α moderately increased TLR1/TLR4 mRNA expression (TNF-α only), and strongly increased TLR2 mRNA expression (IL-1β/TNF-α), with the latter being confirmed on the protein level. Stimulation with IL-1β, TNF-α or Pam3CSK4 (a TLR2-ligand) stimulated IL-6 and IL-8, which was inhibited by a TLR2 neutralizing antibody for Pam3CSK4; IL-1β and TNF-α caused NF-κB activation. HSP60, HSP70 and HMGB1 did not increase IL-6 or IL-8 and were not regulated by IL-1β/TNF-α.

CONCLUSION

We provide evidence that several TLRs are expressed in human IVD cells, with TLR2 possibly playing the most crucial role. As TLRs mediate catabolic and inflammatory processes, increased levels of TLRs may lead to aggravated disc degeneration, chronic inflammation and pain development. Especially with the identification of more endogenous TLR ligands, targeting these receptors may hold therapeutic promise.

Radiological and pathological characteristics of giant cell tumor of bone treated with denosumab

Abstract

We describe a case of giant cell tumor of the proximal tibia with skip bone metastases of the ipsilateral femur in a 20-year-old man. After the neoadjuvant treatment with denosumab, plain radiographs and computed tomography showed marked osteosclerosis and sclerotic rim formation, and ¹⁸F-FDG PET/CT showed a decreased standardized uptake value, whereas magnetic resonance imaging showed diffuse enhancement of the tumor, nearly the same findings as those at pretreatment. Pathological findings of the surgical specimen after the denosumab treatment showed benign fibrous histiocytoma-like features with complete disappearance of both mononuclear stromal cells and multinuclear osteoclast-like giant cells.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1090602085125068

Overexpression of cyclooxygenase-2 in malignant peripheral nerve sheath tumor and selective cyclooxygenase-2 inhibitor-induced apoptosis by activating caspases in human malignant peripheral nerve sheath tumor cells

Background

Cyclooxygenase-2 (COX-2) is a key enzyme in the conversion of arachidonic acid to prostanoids, and its activation is associated with carcinogenesis as well as inflammation. The antitumor effect of selective COX-2 inhibitors has been noted in various malignancies. Malignant peripheral nerve sheath tumor (MPNST) is a rare and aggressive soft tissue sarcoma for which effective treatments have not yet been established. The purpose of this study was to investigate a potential therapeutic role of COX-2 in MPNST.

Methods

We evaluated the expression of COX-2 in 44 cases of high-grade MPNST using immunohistochemical staining and compared the staining results with the characteristics and outcome of the patients. We also investigated the antitumor effect of etodolac, a selective COX-2 inhibitor, on MPNST cells in vitro using the MPNST cell line, FMS-1.

Results

Overexpression of COX-2 (≥50% positive cells) was observed in 29 cases (65.9%), was significantly associated with a poor overall survival (P = 0.0495), and was considered an independent risk factor for a poor outcome by the results of both univariate and multivariate analysis. Etodolac induced apoptosis of FMS-1 cells through the activation of caspase-8, -9, and -3. Moreover, several caspase inhibitors significantly inhibited etodolac-induced apoptosis.

Conclusions

Selective COX-2 inhibitors including etodolac had an antitumor effect on MPNST cells, and their use holds promise as a novel therapeutic strategy for patients with MPNST to improve their prognoses.

Imatinib mesylate inhibits cell growth of malignant peripheral nerve sheath tumors in vitro and in vivo through suppression of PDGFR-β

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive and associated with poor prognosis. Basic research to develop new treatment regimens is critically needed.

METHODS

The effects of imatinib mesylate on MPNSTs were examined in six human MPNST cell lines and in a xenograft mouse model.

RESULTS

The results showed expression of platelet-derived growth factor receptor-β and suppression of its phosphorylation by imatinib mesylate in all six cell lines. Imatinib mesylate effectively suppressed MPNST cell growth in vitro at concentrations similar to those used clinically (1.46 - 4.6 μM) in three of six cell lines. Knockdown of PDGFR-β by transfection with a specific siRNA also caused significant reduction in cell proliferation in the sensitive cell lines, but not in the resistant cell lines. Furthermore, imatinib mesylate also significantly suppressed colony formation within soft agar and tumor growth in xenograft models using two of the three sensitive MPNST cell lines. There was excellent agreement between in vitro and in vivo sensitivity to imatinib mesylate, suggesting possible selection of imatinib-sensitive tumors by in vitro analysis.

CONCLUSIONS

The results suggest that imatinib mesylate may be useful in the treatment of MPNST patients and in vitro studies may help select cells that are sensitive to imatinib mesylate in vivo.

Remitting seronegative symmetrical synovitis with pitting edema syndrome caused by crystal-induced arthritis of the wrist: a case report

OBJECTIVE

To describe a rare case of remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome caused by gouty arthritis.

CLINICAL PRESENTATION AND INTERVENTION

A 76-year-old man presented with swelling and pain in the dorsum of feet and hands bilaterally. From the laboratory and radiologic findings, the diagnosis of gout-induced RS3PE syndrome was made. Conservative therapy with nonsteroidal anti-inflammatory drugs (NSAIDs) and intra-articular corticosteroid injection in the wrist joint completely and rapidly resolved all symptoms. The patient was successfully treated with oral administration of NSAIDs and a one-time intra-articular corticosteroid injection in the left wrist joint.

CONCLUSION

This case demonstrated the importance of considering the possibility of crystal-induced arthritis such as gout and pseudogout, as well as malignant disease, when diagnosing the primary disease responsible for RS3PE syndrome.

Prognostic significance of AKT/mTOR and MAPK pathways and antitumor effect of mTOR inhibitor in NF1-related and sporadic malignant peripheral nerve sheath tumors

PURPOSE

Malignant peripheral nerve sheath tumor (MPNST) is a rare soft tissue sarcoma with poor prognosis. MPNSTs occur frequently in patients with neurofibromatosis type 1 (NF1), in which NF1 gene deficiency leads to Ras hyperactivation. Ras activation causes the subsequent activation of the AKT/mTOR and Raf/MEK/ERK pathways and regulates cellular functions. However, the activation profiles of the AKT/mTOR and MAPK pathways in MPNSTs are poorly understood. The purposes of this study are to examine the correlation between the activation of these pathways and clinicopathologic or prognostic factors and to identify candidate target molecules in MPNST. Moreover, we assessed the antitumor effects of the inhibitor of candidate target.

EXPERIMENTAL DESIGN

Immunohistochemistry was conducted to evaluate the activation profiles of AKT/mTOR and MAPK pathways using 135 tumor specimens. Immunohistochemical expressions were confirmed by Western blotting. Then, an in vitro study was conducted to examine the antitumor effect of the mTOR inhibitor on MPNST cell lines.

RESULTS

Phosphorylated-AKT (p-AKT), p-mTOR, p-S6RP, p-p70S6K, p-4E-BP1, p-MEK1/2, and p-ERK1/2 expressions were positive in 58.2%, 47.3%, 53.8%, 57.1%, 62.6%, 93.4%, and 81.3% of primary MPNSTs, respectively. Positivity for each factor showed no difference between NF1-related and sporadic MPNSTs. Univariate prognostic analysis revealed that p-AKT, p-mTOR, and p-S6RP expressions were associated with poor prognosis. Furthermore, activation of each p-mTOR and p-S6RP was an independent poor prognostic factor by multivariate analysis. mTOR inhibition by Everolimus showed antitumor activity on MPNST cell lines in vitro.

CONCLUSION

mTOR inhibition is a potential treatment option for both NF1-related and sporadic MPNSTs.

Intraosseous spindle cell hemangioma of the calcaneus: a case report and review of the literature

Spindle cell hemangioma, a rare benign tumor characterized by cavernous blood vessels and spindled areas, typically arises in the subcutis of the distal extremities, particularly the hand. The case of intraosseous spindle cell hemangioma is extremely rare, and only 1 case arises in the frontal bone has been reported previously. We describe herein a case of intraosseous spindle cell hemangioma occurring in the left calcaneus in a 65-year-old woman. The patient was successfully treated by the operation. The present case is instructive especially in the differential diagnosis of primary bone tumor structured by spindle cells, for which the possibility of spindle cell hemangioma should be considered.

Pseudogout of the acromioclavicular joint: report of two cases and review of the literature

Although calcium pyrophosphate dehydrate (CPPD) deposition disease, including pseudogout, is a relatively common disease affecting the major joints, especially the knee, pseudogout in the acromioclavicular (AC) joint is very uncommon. We describe two cases of acute pseudogout attacks of the AC joint in elderly patients. Radiological findings showed chondrocalcinosis in the AC joints. Microscopically, aspirated articular synovial fluid demonstrated CPPD crystals. Conservative therapy with non-steroidal anti-inflammatory drugs completely resolved all symptoms within 1 week.