Hiroatsu Nakashima

MRI Features in the Differentiation of Malignant Peripheral Nerve Sheath Tumors and Neurofibromas

OBJECTIVE The objective of this study was to identify the MRI criteria that best differentiate malignant peripheral nerve sheath tumors from benign neurofibromas. MATERIALS AND METHODS We retrospectively analyzed MR images obtained for 41 histologically diagnosed cases of malignant peripheral nerve sheath tumor and 20 cases of neurofibroma that had been treated at four tertiary institutions. Twenty of the patients with malignant peripheral nerve sheath tumors and 14 patients with neurofibromas developed the disease in association with neurofibromatosis 1. The MR images were evaluated with regard to tumor size, signal intensity, heterogeneity of T1- and T2-weighted MR images, enhancement pattern, definition of margins, presence of perilesional edemalike zone, and presence of intratumoral cystic lesions. RESULTS Significant differences between malignant peripheral nerve sheath tumors and neurofibromas were noted for the largest dimension of the mass, peripheral enhancement pattern, perilesional edemalike zone, and intratumoral cystic lesion. In cases associated with neurofibromatosis 1, heterogenicity on T1-weighted images was also significant in differentiating neurofibroma from malignant peripheral nerve sheath tumor. The presence of two or more of the four features suggestive of malignancy indicated malignant peripheral nerve sheath tumor with a sensitivity of 61% and a specificity of 90%. CONCLUSION The MR features described in this study are useful for distinguishing malignant peripheral nerve sheath tumors from neurofibromas. If a tumor has two or more of the four statistically significant features, it can be considered to be highly suspicious of malignancy and should be subjected to a biopsy for early diagnosis.

Soft Tissue Sarcomas of the Chest Wall

Introduction: Soft tissue sarcomas originating from the chest wall include in their definition those originating from the trunk and, in many cases, are analyzed together with retroperitoneal tumors whose clinical results differ, with only a few detailed reports on such tumors strictly limited to the chest wall available. The main purpose of this study was to evaluate the clinical outcomes for patients with chest wall soft tissue sarcomas. Methods: A retrospective review of 44 surgically treated patients was conducted from 1992 to 2006. The median age of the patients was 51.8 years. The median follow-up time was 56.7 months. Twenty-two sarcomas (50.0%) were high-grade, and 22 (50.0%) were low-grade. Of the 44 patients, 31 (70.1%) had previously undergone unplanned excision elsewhere. Histologic examinations of the surgical margins, and oncological outcome for each patient were collected and analyzed. Results: Twenty-six (59.1%) patients were continuously free of disease, 12 were alive and currently free of disease, three were alive with metastasis, and three had died. Local recurrence developed in five patients. The overall survival rate at 5 years was 88.5%. Local recurrence-free survival rate at 5 years was 88.5%. Univariate analyses disclosed age (p < 0.05), high-grade malignancy (p < 0.05), and local recurrence (p < 0.05) as independent predictors of death. Histopathologic examination of the specimens showed that two patients had evidence of bone invasion. Conclusions: The clinical behavior of the chest wall soft tissue sarcomas is similar to that of extremity sarcomas. High-grade tumors are more likely to require a muscle transfer, and it is often very difficult to achieve local control of them in view of their anatomic characteristics. Considering the high local control rate in this study, they are best controlled by adequate wide surgical resection.

Additional wide resection of malignant soft tissue tumors.

Forty-five patients with soft tissue sarcomas received additional wide resections after they were treated with simple excision by a primary physician. Of the patients in the current study, 26 were male and 19 were female; all were treated between 1986 and 1998 for malignant soft tissue tumors. The mean followup was 7.1 ± 3.4 years. The mean time from first excision to additional wide resection was 8 weeks, and for 90% of the patients it was within 12 weeks. In deciding the surgical margin for an additional operation, enhanced computed tomography scans and magnetic resonance images were done. Four (8.8%) patients had local recurrences that required a second resection and had no evidence of disease at latest followup. Four (8.8%) patients had distant metastases but did not have local recurrences. Three patients died of lung metastases. The overall 5-year survival rate of the patients was 93%, and the overall 5-year disease-free rate was 84%. It seems that tumors treated adequately by wide resection in an additional operation have results as good as tumors treated with a primary wide resection.

Osteochondral destruction in pigmented villonodular synovitis during the clinical course.

Objective. In pigmented villonodular synovitis (PVNS), some cases recur and progress to osteochondral destruction. The aim of our study was to clarify the occurrence of osteochondral destruction according to the location of PVNS during the clinical course. Methods. Seventy-two patients with PVNS (43 female, 29 male) with a mean age of 40 years (range 3–87 yrs) had been referred to our institutions. Factors influencing the occurrence of osteochondral destruction were investigated. Results. Mean followup was 60 months (range 12–190 mo). Adjacent bone change occurred in 24 (42%) of 57 patients, who were evaluated at the time of the first consultation. Eight (89%) of 9 patients with hip lesions initially had bone lesions, significantly more frequently than those with other lesions (p = 0.038). Duration of symptoms was significantly correlated with the occurrence of bone lesions in diffuse knee lesions (p = 0.005). During followup, patients with location in the knee had a significantly higher incidence of osteoarthritic change (73%) compared to those with foot and ankle involvement (p = 0.027). Re-operation was more frequently required for knee lesions due to the high recurrence rate (32%). Patients who required re-operation had significantly more marked osteoarthritic change in knees (p = 0.001) during followup than those who did not. Conclusion. For PVNS arising in knees, repeated recurrences followed by re-operation resulted in the progression of osteoarthritic change. PVNS arising in hips, feet, and ankles developed bone lesions initially, probably due to the limited volume of these joints. The indications for re-operation for recurrent knee lesions require careful consideration regarding progression of osteoarthritic change.

Regenerating the fibula with beta-tricalcium phosphate minimizes morbidity after fibula resection.

The aim of this study was to assess the radiologic and clinical outcome when beta-tricalcium phosphate is used as a bone graft substitute to backfill the fibular defect that is created by harvesting the fibula. Fourteen patients who had fibula resections to be used as bone grafts for bone tumor resections were assessed radiographically. Callus formation bridging the beta-tricalcium phosphate was seen in 12 of 14 patients at an average of 1.4 months after surgery. In these 12 patients the beta-tricalcium phosphate mostly was absorbed and replaced by newly formed bone at an average of 9.3 months after surgery. In all children, beta-tricalcium phosphate was replaced by newly formed bone at an average of 3.2 months after surgery. Only one adult patient had complete regeneration of the fibula. Few patients had continuity between the regenerated fibula and the native fibula. In one patient in whom free vascularized fibula was harvested, regeneration of the fibula was not observed. Clinical functional outcome was not correlated with successful fibula regeneration and union with the native fibula, as determined using radiographs. The results of the study suggest that, in children, regeneration of the fibula by implanting beta-tricalcium phosphate into a bone defect can reduce morbidity of the fibula harvest sites. Level of Evidence: Therapeutic study, Level IV (case series—no, or historical control group)

Telomerase, P53 and PCNA activity in osteosarcoma

AIMS The aim of this study was to investigate telomerase activity and to assess the correlation between telomerase activity, tumor proliferative activity and p53 overexpression in osteosarcoma tumor samples. METHODS Using a telomerase polymerase chain reaction-enzyme-linked immunoassay based on the telomeric repeat amplification protocol method, we examined telomerase activity in 26 primary osteosarcoma specimens. P53 overexpression was identified using immunohistochemical staining, and tumor proliferative activity was assessed by immunohistochemical staining of PCNA. RESULTS Telomerase activity was detected at a relatively low level in five of 26 osteosarcoma tissue specimens. P53 was detected in eight of 21 cases. There was no significant correlation between telomerase activity and p53 overexpression (p=0.325). There was a significant correlation between PCNA staining and telomerase activity (p=0.0075). CONCLUSION Difference between the telomerase activity and p53 overexpression in osteosarcoma suggests that p53 and telomerase may not cooperate in tumor proliferation. Correlation of telomerase activity to PCNA expression suggests that telomerase activity may also useful for evaluate proliferative activity in osteosarcoma.

Surgical treatment for fibrous dysplasia of femoral neck with mild but prolonged symptoms: a case series

BackgroundThe proximal femur is one of the most common sites involved by fibrous dysplasia. In cases with mild deformity that does not require corrective surgery, occasional patients suffer sustained pain because of repeated microfractures. This study aimed to clarify the outcomes of surgery with autogenous fibular cortical strut grafting and compression hip screw fixation.MethodsSince 2002, eight consecutive patients (nine hips) with femoral neck fibrous dysplasia without severe deformity were prospectively treated with autogenous fibular strut grafting and compression hip screw fixation.ResultsMean age of patients was 35 years. Mean follow-up of patients after surgery was 75 months. Most of the patients could walk with full weight-bearing 2 weeks after surgery. Functional score of lower extremity was significantly improved from 65 % to 95 % (P = 0.001). Femoral neck angle was increased from 127 to 130. Donor site of strut cortical fibula showed good regeneration with β-tricalcium phosphate.ConclusionsAutogenous fibular cortical strut grafting and compression hip screw fixation achieved good post-operative function and provided an early return to work for adult patients with fibrous dysplasia of the femoral neck with mild but prolonged symptoms. Morbidity in the donor site of fibula strut is minimal with the use of β-tricalcium phosphate.

A study of inter-alpha-trypsin inhibitor chains expression in liposarcomas

AIM Liposarcoma is common soft tissue sarcoma that is sometimes difficult to treat, besides its good prognosis. The inter-alpha-trypsin inhibitor heavy chains (HCs) has been reported to be linked to hyaluronan, which play important roles in tumour progression and metastasis. In this study, clinical significance of HCs in patients with liposarcoma was investigated. METHODS HC expression was studied by immunohistochemistry on resected specimens of 33 liposarcoma patients and 10 lipoma patients. The expression of HC mRNA was analyzed by reverse transcription polymerase chain reaction (RT-PCR). Serum concentration of HC was determined with enzyme-linked immunosorbent assay (ELISA). RESULTS Prominent positive staining of HC was observed in extracellular matrix of pleomorphic and myxoid liposarcoma. In well-differentiated liposarcoma and lipoma, faint staining was seen with HC. No products of HC could be detected by RT-PCR. Serum concentration of HC was not up-regulated in any subtypes of liposarcoma. HC expression was not significantly correlated with tumour subtypes and prognosis. CONCLUSION HC was strongly accumulated in pleomorphic and myxoid liposarcoma, however, was not locally synthesized in liposarcoma. HC might play roles in stabilizing extracellular matrix, such as hyaluronan (HA), in liposarcoma.

Stimulated Type I Collagen Turnover in Patients With Giant Cell Tumor of Bone

The aim of this study was to determine type I collagen turnover in giant cell tumor of bone (GCT) by biochemical markers of type I procollagen aminoterminal propeptide (PINP) and type I collagen carboxyterminal telopeptide (ICTP) as synthesis and degradation markers, respectively. The serum concentrations of PINP and ICTP were measured in 11 patients with GCT using radioimmunoassay, and analyzed by the correlation to the grades of GCT progression described by Campanacci. Serum of the 11 healthy subjects was available for comparison. The serum concentration of PINP was significantly higher in patients with GCT (82.4 ± 46.2 ng/ml) than in controls (40.8 ± 12.1 ng/ml) (P < 0.01), and that of ICTP was also significantly higher in GCT (5.3 ± 2.0 ng/ml) than in controls (3.2 ± 0.8 ng/ml) (P < 0.01). In GCT, the PINP concentration of grade 3 (127.6 ± 38.8 ng/ml) was higher than that in grade 1 patients (46.9 ± 4.8 ng/ml) (P < 0.01). ICTP concentration of both grades 2 (7.1 ± 1.4 ng/ml) and 3 (5.8 ± 1.8 ng/ml) patients was significantly higher than that of grade 1 (3.5 ± 0.6 ng/ml) patients (P < 0.01, P < 0.05, respectively). Two cases of serum concentration of PINP and ICTP after resection of GCT demonstrated that these biomarkers decreased to the control levels in the absence of GCT. Our results indicated that type I collagen turnover evaluated by ICTP and PINP was stimulated in the presence of GCT. Moreover, this enhanced metabolic turnover reflects the grade of GCT.