Factors associated with the decision of operative procedure for proximal femoral bone metastasis: Questionnaire survey to institutions participating the Bone and Soft Tissue Tumor Study Group of the Japan Clinical Oncology Group.

BACKGROUND: Pathological fracture of the proximal femur is a main cause of cancer patients losing their ability to walk. Although both osteosynthetic devices (predominantly intramedullary nails) and prosthetic replacement have been widely performed for treatment, controversies exist regarding which procedure should be used for the various conditions. In order to decide the eligibility criteria of a planned randomized prospective study about the treatment of pathological fractures of the proximal femur, we assessed the factors affecting the selection of operative procedures using questionnaires sent to the members of the Bone and Soft Tissue Tumor Study Group (BSTTSG) of the Japan Clinical Oncology Group (JCOG). METHODS: Questionnaire surveys to evaluate (1) the priority levels of the factors, (2) the equipoise range of each factor in situations where either procedure could be applied, (3) risk and benefit of each procedure, and (4) the degree of bone destruction affecting the selection of operative procedures, were sent to 26 institutions. RESULTS: Over 80% of the institutions answered. Orthopaedic surgeons of BSTTSG decided on the procedure according to the following factors in descending order: life expectancy, performance status before fracture, the degree of bone destruction, walking ability before fracture, general complications, the number of bone metastases in other sites, and the visceral metastasis status. With regard to bone destruction, (1) the involvement of the head, neck, calcar, and intertrochanteric region, (2) transverse destruction >1/2, and (3) soft-tissue tumor extension, were the factors that led to the choice of prosthesis treatment. CONCLUSIONS: Using these identified factors, the inclusion criteria for the prospective randomized study of the surgical treatment of metastatic bone tumors of the proximal femur were optimized. The evaluation system about the bone destruction of metastases needs to be refined through the following prospective randomized study.

A case of intraosseous arteriovenous malformation with unusual radiological presentation of low blood flow.

We report a case of intraosseous arteriovenous malformation (AVM) arising in the diaphysis of the tibia. The patient was a 15-year-old boy who presented with pain in the right lower leg for 3 years. Plain radiographs displayed honeycomb lytic lesions in the right tibial shaft, with slight expansion of the bone and cortical thinning. The lesion was isointense to the muscle on T1-weighted images, and hyperintense on T2-weighted images. An admixture of hypointense small nodular or linear areas on both T1- and T2-weighted images was present within the lesion. Post contrast fat-suppressed T1-images demonstrated a mild heterogeneous increase in signal intensity throughout the tumor. Angiographs showed only faint staining in the lesion. Curettage of the lesion was carried out, and the histological diagnosis of AVM was made. In the context of this patient's lesion, it should be noted that AVM rarely presents as an intraosseous lesion with low blood flow.

Extensive lipoma-like changes of myxoid liposarcoma: morphologic, immunohistochemical, and molecular cytogenetic analyses.

Myxoid liposarcomas (MLSs) with extensive lipoma-like changes (MLSLC) are rare, and it is often difficult to distinguish them from well-differentiated liposarcoma (LS)/dedifferentiated LS (WDLS/DDLS) with myxoid changes. For the characterization of these neoplasms, we studied 8 MLSLCs, 11 ordinary MLSs, 4 WDLSs, and 6 DDLSs. Cytogenetically, MLSLC and ordinary MLS were characterized by t(12;16)(q13;p11) and FUS-DDIT3 fusion gene, whereas WDLS/DDLS lacked the fusion gene but possessed giant marker/ring chromosomes. Both lipoma-like and myxoid components of the same MLSLC exhibited the identical FUS-DDIT3, as confirmed by fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT-PCR). Immunohistochemically, MDM2 and CDK4 were positive in WDLS/DDLS but negative in MLSLC and ordinary MLS. PPARγ, C/EBPα, adipophilin, and perilipin were found in each type of LS. Adipophilin was expressed chiefly in tiny fat droplets of immature lipoblasts, whereas perilipin showed a strong positive staining in large fat vacuoles of signet ring and multivacuolated lipoblasts. The Ki-67 labeling index was lower in the lipoma-like component of MLSLC when compared with the myxoid component of the same tumors as well as ordinary MLS (p < 0.001). When compared with ordinary MLS, MLSLC may be less aggressive in clinical behavior (rare recurrences or metastases) after a wide surgical excision. In conclusion, the distinction between MLSLC and WDLS/DDLS is important, because of the differences of molecular cytogenetic features as well as clinical behaviors between these distinct sarcomas presenting similar morphologic features. In addition, the combined immunohistochemical detection of adipophilin and perilipin may provide a useful ancillary tool for identification of lipoblastic cells in soft tissue sarcomas.

Coexpression of NOR1 and SIX3 proteins in extraskeletal myxoid chondrosarcomas without detectable NR4A3 fusion genes.

Extraskeletal myxoid chondrosarcoma (EMC) is a rare mesenchymal tumor cytogenetically characterized by reciprocal translocations, such as t(9;22)(q22;q12) and t(9;17)(q22;q11), which result in EWSR1/NR4A3 and TAF15/NR4A3 fusion genes (alias EWS/NOR1, TAF2N/NOR1), respectively. NOR1 is an orphan nuclear receptor and acts as a transcription factor that can bind to its putative coactivator, SIX3. Although the NOR1 fusion protein has been implicated in oncogenesis of EMC, a small fraction of EMC lacks detectable rearrangements of the NR4A3 gene or 9q22. We report a case of EMC with no detectable NR4A3 gene alterations, as assessed with various molecular techniques including reverse transcription-polymerase chain reaction (RT-PCR), Southern blotting, interphase fluorescence in situ hybridization, and PCR single-strand conformation polymorphism-but with coexpression of native NOR1 and SIX3. In our survey of another 18 EMCs, we identified one more case expressing both NOR1 and SIX3 but lacking NR4A3 fusion. Fourteen tumors with detectable NR4A3 fusion genes (EWSR1-NR4A3; TAF15-NR4A3) expressed neither native NOR1 nor SIX3. SIX3 expression is normally confined specifically to the developing eye and fetal forebrain, although the expression of NR4A3 is largely ubiquitous. Our data suggest that aberrant coexpression of NOR1 and SIX3 is a potential alternative mechanism underlying the development of EMC.

Low-grade fibromyxoid sarcoma with prominent giant rosettes and heterotopic ossification.

Low-grade fibromyxoid sarcoma is a rare soft tissue sarcoma of fibroblastic differentiation characterized by a deceptively benign morphologic appearance with almost consistent MUC4 expression and recurrent chromosomal translocations, t(7;16)(q34;p11) and t(11;16)(p11;p11), resulting in the FUS-CREB3L2 and FUS-CREB3L1 fusion genes, respectively. A subset of the tumors show peculiar histologic features, designated as giant rosettes, and were formerly referred to as hyalinizing spindle cell tumor with giant rosettes. We herein report a case of low-grade fibromyxoid sarcoma showing the presence of numerous giant rosettes, with and without collagenous centers, distributed throughout the lesion and unusual rim-like heterotopic ossification. Such a case might present a diagnostic challenge. The diagnosis of the tumor was confirmed by positive immunoreactivity to MUC4 and the FUS-CREB3L2 fusion detected by molecular testing using formalin-fixed, paraffin-embedded tissue. This case, which has such unusual clinicopathologic features, would help to further expand our knowledge regarding the morphologic diversities of low-grade fibromyxoid sarcoma.

Spinal epithelioid hemangioendothelioma with epithelioid angiosarcomatous areas.

Epithelioid hemangioendothelioma is a distinctive vascular tumor rarely involving bones. We report a case of epithelioid hemangioendothelioma in the cervical spine with angiosarcomatous areas. A 50-year-old female presented with dizziness while walking. A mixed sclerotic and osteolytic or destructive lesion was radiographically disclosed in her upper cervical vertebrae. Histologically, a laminectomy specimen exhibited areas of ordinary epithelioid hemangioendothelioma together with foci of more atypical epithelioid cell proliferation, closely resembling epithelioid angiosarcoma. This phenomenon has been exceptionally described in cases with skeletal lesions, which are typically of low-grade malignancy.