Gluteal Compartment Syndrome After Femoral Nail Extraction: A Case Report.

Gluteal compartment syndrome is a rare disorder and no definitive treatment has yet been established. Fasciotomy is often the treatment of choice for gluteal compartment syndrome, but there have been only a few cases that have improved with conservative therapy. A 26-year-old male with a body mass index of 40.5 who underwent femoral nail extraction surgery had severe pain in the right buttock and numbness in the right lower extremity. Initially, we suspected transient pain due to prolonged exposure to the same posture, but muscle weakness in the lower extremities and worsening of renal function appeared over time. Orthopedic evaluation revealed physical examination findings and MRI imaging findings consistent with gluteal compartment syndrome. Conservative treatment with temporary dialysis was chosen instead of fasciotomy because of the time required for diagnosis. Dialysis was started on postoperative day 3, renal function and muscle weakness recovered over time, and the patient was discharged home on postoperative day 37. At six months post-op, the patient was walking without pain and he had no changes in his peripheral neurologic examination compared to his preoperative baseline. Orthopedic surgeons should always be aware of the possibility of gluteal compartment syndrome when especially obese patients with prolonged operation times appeal to acute buttock pain. Diagnosis should be made as early as possible to get a good prognosis.

Bisphosphonates Prescription for Patients With Hip Fractures Based on Evaluation by a Dentist.

Background The purpose of this study is to clarify the current status of the prescription of postoperative bisphosphonates for patients with hip fractures and to explore the factors that prevent the postoperative prescription of bisphosphonates. Methods Of 180 patients with hip fractures treated surgically at our hospital between August 2019 and April 2020, 149 patients (46 men and 103 women; mean age: 83.9 ± 9.0 years), excluding 31 patients already prescribed bisphosphonates or denosumab, were included in the study. All patients were treated based on our clinical pathway, and their risk of jaw osteonecrosis was evaluated prior to the initiation of bisphosphonates by a dentist in our hospital. We collected data from the medical records on osteoporosis treatment interventions at admission and discharge, the reasons why postoperative bisphosphonates could not be prescribed at discharge, the proportion of patients who had follow-ups at our hospital, and patients' osteoporosis treatment status. Results Eighteen (12.8%) and 95 (63.8%) patients were prescribed anti-osteoporosis drugs at admission and discharge, respectively. One hundred and twenty-one patients (86.8%) could not be prescribed postoperative bisphosphonates at discharge - 71 (58.7%) because of oral hygiene problems, 34 (28.1%) because they did not have regular dental consultations, seven (5.8%) because of renal dysfunction, eight (6.6%) because of poor cognitive and swallowing function, and one (0.8%) because of medication side effects. Forty-nine patients (32.9%) went to our hospital for follow-up and 11 were introduced to bisphosphonates or denosumab at follow-up. Conclusions The number of patients with hip fractures who were prescribed postoperative bisphosphonates was low in our study. The oral hygiene problems identified by dentists accounted for responsible for the low prescription rate of postoperative bisphosphonates. Therefore, coordination with dentists may be important to increase the postoperative bisphosphonate prescription.

Co-existence of Lumbar Disc Herniation and Posterior Ring Apophyseal Fracture: It Is Not Rare and Computed Tomography Is Useful.

Introduction Posterior ring apophyseal fracture (PRAF) is characterized by the separation of bone fragments and sometimes coexists with lumbar disc herniation (LDH). However, how often these conditions coexist and the details of the clinical course remain unclear. Methods We analyzed 200 patients who underwent surgical treatment for LDH at our hospital from January 2016 to December 2020. Among these, we reviewed 21 patients who underwent microendoscopic surgery to treat PRAF. They consisted of 11 male and 10 female patients, ranging in age from 15 to 63 years. The average age was 32.8 months, and the average follow-up period was 39.8 years. We performed simple roentgenography and magnetic resonance imaging for all patients and computed tomography for about 80% of the patients. We evaluated the type of PRAF fragment (Takata classification), disease level, Japanese Orthopedic Association (JOA) score, Roland-Morris Disability Questionnaire (RDQ) score, operating time, intraoperative blood loss, and perioperative complications. Results A total of 10.5% of patients with LDH also had PRAF. The mean JOA score significantly improved from 10.6 ± 5.7 points before surgery to 21.4 ± 5.1 points at the final observation (p < 0.05). The mean RDQ score significantly improved from 17.1 ± 4.5 preoperatively to 5.5 ± 0.5 at the final observation (p < 0.05). The average operation time was 88.6 minutes. There were no complications requiring early surgery that were due to postoperative infection or epidural hematoma, but one patient required reoperation. Conclusion This study showed that PRAF coexisted with LDH in about 10% of cases, and the outcomes of surgical treatment were generally good. Computed tomography is recommended to improve the diagnostic rate and assist with surgical planning and intraoperative decision-making.

Efficacy of Corticosteroid Addition to a Periarticular Cocktail Injection to Counteract Nausea and Vomiting After Total Knee Arthroplasty.

BACKGROUND: Intraoperative periarticular injection of a "cocktail" of drugs is undertaken commonly in total knee arthroplasty (TKA). The addition of a corticosteroid to the periarticular injection is believed to offer greater pain relief because of its local anti-inflammatory effects, but the prevalence of postoperative nausea and vomiting (PONV) is not known. This retrospective observational study aimed to elucidate the relationship between corticosteroid addition to a periarticular cocktail injection (PCI) and PONV. MATERIALS AND METHODS: Fifty-nine patients who underwent unilateral TKA for primary osteoarthritis were divided into two groups: corticosteroid and non-corticosteroid. The former had triamcinolone acetonide (40 mg) added to the same PCI. The primary outcome was the prevalence of nausea and vomiting within 48 hours following TKA. RESULTS: There was no significant difference between the two groups in terms of patient demographics. The overall prevalence of PONV was 16.9%. Fewer patients in the corticosteroid group complained of PONV than in the non-corticosteroid group (6.4% vs. 58.3%; p = 0.012). CONCLUSIONS: The addition of a corticosteroid to a PCI suppressed PONV. Our results suggested that cocktail injections may have local and systemic effects.

Factors Affecting Postoperative Spinal Epidural Hematoma and the Optimal Order of Vertebral Body Decompression in Multivertebral Microendoscopic Laminectomy.

Purpose Symptomatic postoperative spinal epidural hematoma (POSEH) is a complication of spine surgery that occurs infrequently but may cause ongoing serious neurological damage. Due to the narrow entry portal, the risk of hematoma is increased after microendoscopic laminectomy (MEL) compared with conventional open surgery, and the risk might be even higher for multivertebral MEL (m-MEL). The purpose of this study was to clarify the factors affecting the development of POSEH after m-MEL and identify the optimal order for the decompression of vertebral bodies. Methods A total of 313 patients who underwent m-MEL from 2016 to 2020 were retrospectively assessed. The cohort comprised 238 patients who underwent two-level MEL, 67 who underwent three-level MEL, and eight who underwent four-level MEL. Symptomatic POSEH was defined as the presence of an epidural hematoma at the surgical site on MRI with symptoms such as lower extremity pain or muscle weakness. We elucidated the incidence of POSEH at each vertebral level and investigated the relationship between POSEH and possible risk factors such as clinical and operative variables. Results There were 41 patients in the POSEH group and 272 patients in the non-POSEH group. Seven patients in the POSEH group underwent reoperation. The occurrence of POSEH was related to the number of decompressed vertebral bodies. Patients who underwent L2/3 and L3/4 decompression at the end of the procedure also showed a higher incidence of POSEH at the surgical level. Conclusion In patients undergoing m-MEL, treatment of the upper lumbar vertebrae at the end of decompression surgery might be a risk factor for symptomatic POSEH. The incidence of POSEH was particularly increased at L2/3, suggesting that L2/3 decompression should not be performed at last and that careful hemostasis should be applied.

A Case of Delayed Airway Stenosis Due to Retropharyngeal Hematoma Caused by Low Energy Trauma.

Airway narrowing due to trauma-induced retropharyngeal hematoma is rare. However, it is dangerous to overlook this lesion because it can lead to airway obstruction and even death. In this article, we report a case of a patient who developed pharyngeal pain and dysphagia two days after bruising on the forehead due to a fall and required intubation management. A 52-year-old man fell while walking and bruised his forehead two days before visiting our hospital. He had a sore throat and dysphagia two days after the injury and came to our hospital three days after the injury. The swelling was observed in the anterior neck, and stenotic sounds were heard in the upper airway. Cervical CT and MRI of the cervical spine showed extensive hyperabsorption areas in the ventral side of the cervical spine that appeared to be hematomas. No fracture of the cervical spine was observed. The patient has been placed on emergency tracheal intubation due to concerns about airway stenosis caused by the hematoma. Although pneumonia was observed during treatment, it resolved with antimicrobial therapy, and the hematoma tended to shrink, so the patient was extubated on the 15th day of admission. However, the patient was intubated again on the 17th day of hospitalization due to poor oxygenation. A tracheostomy was performed on the 26th day of hospitalization due to suspected narrowing of the upper airway caused by hematoma or sputum. On day 59 of hospitalization, the cannula was removed, and the patient was discharged home on the 68th day after hospitalization. Low-energy trauma tends to be underrecognized as producing anterior cervical hematomas that can lead to fatal airway narrowing. Care should be taken because fatal anterior cervical hematomas are not often part of the differential diagnosis due to their often delayed onset. More caution is needed if an underlying disease may cause coagulation abnormalities.

Efficacy of Nerve Root Block for the Treatment of Lumbar Spinal Canal Stenosis in Adults Older Than 80 Years of Age.

BACKGROUND: Patients with advanced lumbar spinal canal stenosis (LCS) often prefer non-operative treatment owing to decreased physiological function and comorbidities. Although the therapeutic value of selective nerve root block (SNRB) for LCS is confirmed, there are few reports of its effectiveness in the elderly. We investigated the efficacy of SNRB for LCS in patients over 80 years of age. METHODS:  The subjects were 112 patients aged over 80 years (mean age: 84 years; 45 men and 67 women ) with medication-resistant LCS without cauda equina syndrome who underwent SNRB. Cases with acute-onset lumbar disc herniation were excluded. We retrospectively investigated and compared the presence or absence of surgery, effect of SNRB, number of procedures, duration of disease, and magnetic resonance imaging findings. Patients who could avoid the surgery by SNRB were defined as the effective group. Patients whose symptoms were not relieved by SNRB and who underwent surgery and those whose symptoms were not relieved but who continued conservative treatment were defined as the ineffective group. A total of one to seven SNRBs were performed in both groups, and the same spine surgeon performed the entire procedure from SNRB to surgery. RESULTS:  There were 86 nonoperative patients (69 effective cases) and 26 operative patients; the overall rate of effectiveness was 61% (69/112 patients). The area of the spinal canal at the responsible level was 108.63 mm2 in the effective group compared with 77.06 mm2 in the ineffective group. This was significantly narrower in the ineffective group (p=0.0094). There was no significant difference in the duration of illness, number of blocks, or hernia complication rate between the groups. No patient experienced severe neuralgia that may have been caused by neuropathy during SNRB. DISCUSSION: Our outcome showed that more than 60% of older patients with LCS showed symptomatic improvement with SNRB. SNRB can be performed relatively safely in the elderly and appears to be a favorable treatment option for older patients with various risks, such as poor general condition. CONCLUSIONS: Multiple sessions of SNRB may provide older patients with symptomatic improvement and may be an option for treatment.

Full-Endoscopic Lumbar Discectomy for Recurrent Lumbar Disc Herniation: A Retrospective Study with Patient-Reported Outcome Measures.

INTRODUCTION: Revision surgery for recurrent lumbar disc herniation after surgical treatment is at times challenging due to epidural adhesions and scar. This study aimed to review the clinical results and safety of full-endoscopic lumbar discectomy via interlaminar (FELD-IL) and transforaminal (FELD-TF) approaches for revision surgery. METHODS: We conducted a retrospective study including 52 lumbar disc herniation revision patients (mean age, 51.8 years; male/female, 13/39), with 17 FELD-IL and 35 FELD-TF cases. Complication incidences were assessed by reviewing surgical videos and postoperative magnetic resonance images of nerve decompression outcomes. Patients' responses to Japan Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and numerical rating scales (NRS) for lumbar pain, leg pain, and leg numbness were recorded before and during follow-up. The Wilcoxon-signed rank tests were utilized to compare pre- and postoperative group variables. RESULTS: The average operation time was 33.0 min in FELD-IL and 31.7 min in FELD-TF. Seven FELD-IL cases required lamina excavation with high-speed drill bars for scar tissue dissection from the lamina. Dura injury occurred during the excavation in one case. No complication was noted in the FELD-TF group. Successful decompression of the nerve was achieved in all cases. Complete sets of JOABPEQ and NRS were obtained in 64.5% of FELD-IL and in 82.9% of FELD-TF. The mean follow-up period was 18.6 months. All the subdomain of JOABPEQ and NRS improved significantly postoperative in both groups. There was no difference regarding the improvement of scores between the procedures except NRS for lumbar pain, which was more favorable in FELD-IL. Recurrence of herniation occurred in one patient (6%) after FELD-IL and two patients (6%) after FELD-TF. CONCLUSIONS: Both FELD-IL and FELD-TF are safe and effective revision procedures for recurrent lumbar disc herniation. FELD-TF could be performed employing the same procedure as primary surgery in revisions, regardless of the previous surgical approach.

Overexpression of A disintegrin and metalloproteinase 28 is correlated with high histologic grade in conventional chondrosarcoma.

Low-grade chondrosarcoma and enchondroma are occasionally difficult to differentiate solely by reference to clinicoradiologic and histologic findings. The A disintegrin and metalloproteinases are a new gene family of proteins having a metalloprotease domain with matrix metalloproteinases and play an important role in the chondrocyte development process. Therefore, we analyzed the expression of A disintegrin and metalloproteinases and matrix metalloproteinases in several kinds of cartilaginous bone tumors at the messenger RNA level and immunohistochemical protein level and ascertained their relationships to the histologic degree of malignancy. Reverse transciptase-polymerase chain reaction and real-time quantitative reverse transciptase-polymerase chain reaction of the expression of the A disintegrin and metalloproteinase family in cartilaginous bone tumors demonstrated that A disintegrin and metalloproteinase 28 messenger RNA levels in grade I chondrosarcoma were significantly higher than those in enchondroma (P = .009). Moreover, positive immunoreactivity of A disintegrin and metalloproteinase 28 was observed in 12 (59%) of 22 patients with grade I chondrosarcoma and in 21 (91%) of 23 patients with grade II chondrosarcoma, respectively. In contrast, only 2 (9%) of 21 cases of enchondromas demonstrated positive staining for A disintegrin and metalloproteinase 28. On the other hand, the immunohistochemical expressions of matrix metalloproteinase 9 and matrix metalloproteinase 13 were significantly higher in enchondromas than in normal cartilage tissue; however, there is no statistically different expression between enchondromas and grade I chondrosarcomas. We detected that overexpression of A disintegrin and metalloproteinase 28 was increased according to its histologic grade in conventional chondrosarcoma and could be one of the helpful tools in distinguishing between low-grade chondrosarcoma and enchondroma.

Infrequent SMARCB1/INI1 gene alteration in epithelioid sarcoma: a useful tool in distinguishing epithelioid sarcoma from malignant rhabdoid tumor.

Loss of SMARCB1/INI1 protein expression is considered useful for confirming a histologic diagnosis of malignant rhabdoid tumor. However, loss of SMARCB1/INI1 protein expression has recently been reported in other tumors as well, including a few cases of epithelioid sarcoma. In addition, the histopathologic differences between proximal-type epithelioid sarcoma and malignant rhabdoid tumor have not been conclusively defined. We analyzed SMARCB1/INI1 protein expression in 54 epithelioid sarcoma (proximal-type, 25; distal-type, 29) and examined alterations of the SMARCB1/INI1 gene in the cases lacking protein expression. We found that 19 (76.0%) proximal-type epithelioid sarcoma and 27 (93.1%) distal-type epithelioid sarcoma showed loss of SMARCB1/INI1 protein expression. Analysis of 39 cases with loss of protein expression revealed 4 cases (10.3%) with SMARCB1/INI1 gene alterations at the DNA level (homozygous deletion, 2; 1- or 2-bp deletion, 2) that could have induced the loss of gene products, and all 4 of these were proximal-type epithelioid sarcoma. Epithelioid sarcoma was thus associated with a high frequency of loss of SMARCB1/INI1 protein expression similar to that in malignant rhabdoid tumor. However, the frequency of SMARCB1/INI1 gene alteration at the DNA level in proximal-type epithelioid sarcoma was significantly lower than that in malignant rhabdoid tumor. In addition, the prognosis of patients with malignant rhabdoid tumor is significantly worse than that of patients with proximal-type epithelioid sarcoma (P = .001). Therefore, proximal-type epithelioid sarcoma and malignant rhabdoid tumor are suggested to be distinctive tumors with respect to the mechanism of the loss of SMARCB1/INI1 protein expression. Analysis of alterations in the SMARCB1/INI1 gene may thus be a useful diagnostic tool to distinguish proximal-type epithelioid sarcoma from malignant rhabdoid tumor.

SMARCB1/INI1 protein expression in round cell soft tissue sarcomas associated with chromosomal translocations involving EWS: a special reference to SMARCB1/INI1 negative variant extraskeletal myxoid chondrosarcoma.

Several previous studies have demonstrated the lack of SMARCB1/INI1 protein expression in only the malignant rhabdoid tumor (MRT). Several sarcoma groups are associated with a tumor-specific translocation involving EWS. Moreover, the EWS and SMARCB1/INI1 genes are located on the same 22q chromosome. We analyzed the status of SMARCB1/INI1 protein expression in 93 cases of sarcomas associated with chromosomal translocation involving EWS, comprising 52 Ewing's sarcoma/primitive neuroectodermal tumors, 24 extraskeletal myxoid chondrosarcomas (EMCS), 14 clear cell sarcomas of soft tissue, 2 desmoplastic small round cell tumors, and 1 myxoid/round cell liposarcoma. In addition, we analyzed the detailed SMARCB1/INI1 gene alteration in cases, which lacked its protein expression. Consequently, 4 EMCS showed no SMARCB1/INI1 expression, and 2 of these 4 cases revealed homozygous deletion and frameshift mutation of the SMARCB1/INI1 gene, respectively. These cases showed histologic findings compatible with EMCS, according to the most recent WHO classification, but no major fusion gene transcripts were detected. Moreover, 3 out of 4 SMARCB1/INI1 negative variant EMCS disclosed rhabdoid features. Therefore, the lack of SMARCB1/INI1 protein expression may be associated with rhabdoid features. The immunohistochemical result of the SMARCB1/INI expression is not an absolute diagnostic criteria for MRT and careful histologic evaluation is required to make a precise diagnosis of MRT.

Highly aggressive behavior of malignant rhabdoid tumor: a special reference to SMARCB1/INI1 gene alterations using molecular genetic analysis including quantitative real-time PCR.

PURPOSE: SMARCB1/INI1, which negatively regulates cell cycle progression from G0/G1 into the S-phase via the p16INK4a-RB-E2F pathway, has been reported to be inactivated homozygously by deletion and/or mutations in malignant rhabdoid tumor (MRT). In the current study, we investigated the alteration of the SMARCB1/INI1 gene using simple methods, and its gene product at the protein level. Moreover, we investigated the status of hyperphosphorylation in RB protein, known as a key cell cycle molecule. METHODS: Three cell lines and 11 formalin-fixed, paraffin-embedded specimens of MRT were investigated. SMARCB1/INI1 gene alteration was analyzed with simple methods as a quantitative real-time PCR and direct sequencing method. Furthermore, SMARCB1/INI1 and RB protein were immunohistochemically evaluated. RESULTS: In 12 of 14 cases, we detected genetic alterations comprised of nine (including three cell lines) homozygous deletions and three mutations, which can induce abnormal expression of gene products. At the protein level, SMARCB1/INI1 immunohistochemical expressions were not detected in any cases. Twelve out of 14 cases showed high-level (+5) expression of tRB (both hyperphosphorylated and underphosphorylated RB), combined with low-level (+1) expression of uRB (underphosphorylated RB), indicating a high rate of hyperphosphorylation. CONCLUSIONS: We could analyze the SMARCB1/INI1 gene alteration with simple methods, and SMARCB1/INI1 gene alteration was found in 12 of 14 cases. Especially, quantitative real-time PCR was a convenient and accurate method. In addition, a high rate of hyperphosphorylation of RB gene was recognized. These results suggest that the clinically aggressive character of MRT is caused by the inactivation of the SMARCB1/INI1 gene.

Detection of COL1A1-PDGFB fusion transcripts and PDGFB/PDGFRB mRNA expression in dermatofibrosarcoma protuberans.

Fusion of the collagen type I alpha 1 (COL1A1) gene with the platelet-derived growth factor beta chain (PDGFB) gene has been described in dermatofibrosarcoma protuberans. The abnormal fusion transcripts probably cause PDGFB and its receptor (platelet-derived growth factor receptor beta, PDGFRB) autocrine stimulation and cell proliferation, which are responsible for the development of dermatofibrosarcoma protuberans. A reverse transcription-polymerase chain reaction assay was performed to detect the COL1A1-PDGFB fusion transcripts in 57 samples. In addition, the PDGFB gene amplification and PDGFB/PDGFRB mRNA levels were quantified by a real-time PCR system for the samples in which the fusion transcripts had been successfully detected. The fusion transcripts were detected in 42 of 57 samples. Various exons of the COL1A1 gene were fused in frame with the PDGFB gene; exons 7 and 25 were found to be slightly more frequently involved than the other exons. The PDGFB gene amplification levels varied from 0.6 to 8.3 (mean 2.4) in 42 tumor samples and from 0.4 to 3.0 (mean 1.2) in 20 adjacent normal tissue samples. In the 20 paired samples, the PDGFB gene amplification in the tumor was significantly higher than that in the normal tissue. The presence of PDGFB and PDGFRB mRNAs was demonstrated in 26 and 21 of 26 cases, respectively. The PDGFB and PDGFRB mRNA expression levels showed a good correlation (r=0.76, P<0.0001). These results indicate that the fusion protein, which is processed by the COL1A1-PDGFB transcripts, can serve as a functional ligand for PDGFRB.

Pigmented villonodular synovitis with chondroid metaplasia, resembling chondroblastoma of the bone: a report of three cases.

We herein describe three cases of pigmented villonodular synovitis with chondroid metaplasia. Two cases involved the temporomandibular joint, whereas the remaining one case occurred in the hip joint. Histologically, the tumors showed a villous pattern and were mainly composed of histiocyte-like cells and scattered osteoclast-like multinucleated giant cells, accompanied by chondroid areas with occasional lace-like calcification. These features resembled those of chondroblastoma of the bone, with the exception of the villous pattern. The histiocyte-like cells showed positive immunoreactivity for CD68, whereas they were negative for S-100 protein. Some of the previously reported cases of chondroblastoma in the temporal bone may have actually been cases of pigmented villonodular synovitis with chondroid metaplasia. When histologically chondroblastoma-like lesions involve the temporal bone or temporomandibular joint, the possibility of pigmented villonodular synovitis with chondroid metaplasia should also be considered, in addition to chondroblastoma of the bone. The correlation between this lesion and synovial chondromatosis remains uncertain.

Dysadherin expression as a significant prognostic factor and as a determinant of histologic features in synovial sarcoma: special reference to its inverse relationship with E-cadherin expression.

Dysadherin is a cancer-associated cell membrane glycoprotein, which down-regulates E-cadherin and promotes metastasis. Synovial sarcoma is a very rare mesenchymal tumor that exhibits an epithelial profile. To confirm the diagnosis of synovial sarcoma, we evaluated several immunohistochemical markers, or detected SYT-SSX fusion gene transcript. We studied the clinicopathologic features in 92 synovial sarcoma patients and also assessed the immunohistochemical expression of dysadherin and E-cadherin to examine their possible association with histologic subtype and biologic behavior. Moreover, among 30 patients, for whom frozen materials were available, dysadherin mRNA expression was examined by reverse transcription-polymerase chain reaction and real-time quantitative reverse transcription-polymerase chain reaction analysis. Dysadherin-positive expression was significantly correlated with E-cadherin-reduced expression (P=0.0004). Dysadherin-positive immunostaining was diffusely observed in the membranes of tumor cells in 30/68 (44%) patients with monophasic fibrous type and in 1/2 (50%) patients with poorly differentiated type. However, in biphasic tumors, dysadherin expression in the fibrous component was not diffusely observed, but often sporadically or focally observed [20/22 (91%) patients]. In addition, dysadherin mRNA expression in monophasic fibrous type was significantly higher than in biphasic type (P=0.0079). Synovial sarcoma patients with dysadherin expression survived for a significantly shorter time than those without dysadherin expression (P=0.0006). Patients with combined dysadherin-positive expression and E-cadherin-reduced expression had a significantly worse prognosis than those with other combinations of dysadherin and E-cadherin expression (P=0.0007). SYT-SSX fusion gene transcript was detected in 39 patients. In our series, SYT-SSX fusion type was found to have no correlation with histologic subtype, prognosis, or dysadherin expression. In multivariate analysis, dysadherin immunopositivity (P=0.0411) was an independent adverse prognostic factor, in addition to a high MIB-1 labeling index (> or =10%). We conclude that E-cadherin dysfunction by dysadherin is associated with reduced E-cadherin expression and morphologic change from epithelioid to spindle phenotype. Dysadherin expression is considered to be one of the determinants of histologic subtype in synovial sarcoma. Moreover, dysadherin expression is an excellent and independent prognostic indicator.

Intramuscular diffuse-type giant cell tumor within the hamstring muscle.

Diffuse-type giant cell tumor (D-TGCT) is known as a synonym for pigmented villonodular synovitis (PVS), a condition usually found in the large joints. We report an extremely rare case of D-TGCT which was located within the hamstring muscle. The lesion was an incidental finding in a 62-year-old man who underwent positron emission tomography (PET) as part of a staging evaluation for gastric cancer. The lesion was resected. There has been neither metastasis nor recurrence during the 6-month period since resection. This case demonstrates that PVS/D-TGCT may have a high SUV on PET imaging, and for this reason PET may be useful for detecting both the tumor and any recurrence.

Prognostic significance of dysadherin expression in epithelioid sarcoma and its diagnostic utility in distinguishing epithelioid sarcoma from malignant rhabdoid tumor.

Dysadherin is a cancer-associated cell membrane glycoprotein, which downregulates E-cadherin and promotes metastasis. We studied the clinicopathological features in 72 cases of epithelioid sarcoma and in six cases of malignant rhabdoid tumor, and also assessed the immunohistochemical expression of dysadherin, E-cadherin and MIB-1 in epithelioid sarcoma and malignant rhabdoid tumor cases. In addition, we compared dysadherin mRNA expression between epithelioid sarcoma and malignant rhabdoid tumor cell lines, using RT-PCR and real-time quantitative RT-PCR analysis. Immunohistochemical dysadherin expression was more frequently observed in proximal-type epithelioid sarcoma (71%) in comparison with distal-type epithelioid sarcoma (36%) (P = 0.037). Furthermore, seven proximal-type epithelioid sarcoma cases mimicking malignant rhabdoid tumor (histologically classified as the large cell type, accompanied by frequent rhabdoid cells and located in deep soft tissue) were all positive for dysadherin (100%), whereas dysadherin expression was not detected at all in any of the true six malignant rhabdoid tumors (0%). Cell lines established from proximal-type epithelioid sarcoma revealed significantly higher levels of dysadherin mRNA expression, compared with the levels seen in malignant rhabdoid tumor cell lines by real-time quantitative RT-PCR (P = 0.0433). Epithelioid sarcoma patients with dysadherin expression survived for a significantly shorter time than those without dysadherin expression (P = 0.001). In multivariate analysis, dysadherin immunopositivity (P = 0.0004) was one of the two independent adverse prognostic factors. We conclude that dysadherin expression in epithelioid sarcoma is a significant poor prognostic factor and that it is a powerful diagnostic marker for distinguishing epithelioid sarcoma, including the proximal-type epithelioid sarcoma, from malignant rhabdoid tumor. In epithelioid sarcoma, especially in proximal-type epithelioid sarcoma, increased cell disadhesion and motility by dysadherin plays an important role to acquire aggressive biological behavior. However, in malignant rhabdoid tumor, cell growth cycle that is regulated by hSNF5/INI1 gene seems to be critical to lethal biological behavior rather than dysadherin.

Aberrant expression of CHFR in malignant peripheral nerve sheath tumors.

Mitotic checkpoint maintains genomic integrity before mitosis. Numerous observations have suggested that mitotic abnormalities produce chromosomal instability and aneuploidy. In MPNST, complex karyotypes showing numerical and structural aberrations have been described. 'Checkpoint with forkhead-associated domain and ring finger' (CHFR) was recently identified as defining a new early mitotic checkpoint. We examined the expression of CHFR in 96 cases of MPNST by immunohistochemical and molecular methods. We found reduced (score, < or = 3) expression of CHFR in 63 out of 96 (66%) cases of MPNST, and such alteration was significantly correlated with a high mitotic count, a high Ki-67-labeling index, and a poor prognosis. In addition, MPNST with normal karyotype showed a strong (score, =5) expression of CHFR. Our results support the assertion that CHFR functions as an inhibitor of tumor proliferation.

Chromosomal aberrations and microsatellite instability of malignant peripheral nerve sheath tumors: a study of 10 tumors from nine patients.

Malignant peripheral nerve sheath tumor (MPNST) is an uncommon soft tissue neoplasm with a poor prognosis, occurring sporadically or associated with neurofibromatosis type 1 (NF1); however, the histogenesis of MPNST remains unclear, especially in sporadic tumors. There are two major forms of genomic instability in human cancer: chromosomal instability (CIN) and microsatellite instability (MSI). An inverse relationship has recently been demonstrated between CIN and MSI in colorectal cancers. CIN and MSI are suggested to be individual pathways, which are involved in the pathogenesis and which may lead to specific clinical and pathological characteristics. To elucidate the chromosomal aberration as a consequence of CIN and MSI status of MPNST, we karyotyped 10 MPNSTs from nine patients, and examined the MSI of seven microsatellite markers using high-resolution fluorescence microsatellite analysis; 2 out of 10 cases (20%) had normal karyotypes, and 8 out of 10 cases (80%) revealed structural and numerical chromosomal aberrations. Three of the 10 cases (30%) showed near triploidy. The most frequent aberration was -22 (40%), followed by +2, +14, -13, -17, and -18 (30% each). An MSI-low status was observed in 30% of cases; the remaining cases showed microsatellite stability. These findings suggest that chromosomal aberration as a consequence of CIN has a greater role in the pathogenesis of MPNST than does that due to MSI.

Alterations of the RB1 gene in dedifferentiated liposarcoma.

Dedifferentiated liposarcoma is a malignant adipocytic neoplasm containing a non-lipogenic sarcoma of variable histological grade that arises against the background of a pre-existing well-differentiated liposarcoma. The phenomenon of dedifferentiation is considered to be time-dependent, but the mechanism is not well known. The retinoblastoma protein, encoded by the RB1 gene located at 13q14, is a key regulator of proliferation, development, and differentiation of certain cell types, including adipocytes. In the current study, we investigated the genetic alterations of the RB1 gene, such as mutation (the essential promoter region and the protein-binding pocket domain; exons 20-24) and methylation of the promoter region, in addition to pRB expression and loss of heterozygosity (LOH) status, in two morphologically distinct areas (non-lipogenic dedifferentiated and well-differentiated components) in 27 patients. As a control, 11 undifferentiated high-grade pleomorphic sarcoma/pleomorphic malignant fibrous histiocytoma samples and 11 well-differentiated liposarcoma samples were also evaluated. Dedifferentiated components showed LOH (15/25; 60%) and abnormal retinoblastoma protein expression (18/27; 66.7%) more frequently than noted in the well-differentiated components (3/24; 12.5% and 9/27; 33.3%, respectively). Five and four out of the 27 dedifferentiated components harbored mutations and promoter methylation, respectively, whereas none of these alterations were seen in the well-differentiated components. These results suggest that retinoblastoma protein has a major role to play in dedifferentiation and that a 'two-hit' mechanism is involved in the altered retinoblastoma protein expression in dedifferentiated liposarcoma.