A dedifferentiated liposarcoma of the anterior mediastinum

Dedifferentiated liposarcoma was first described in 1979, and its definition has been recently extended. We found an undiagnosed anterior mediastinal mass in a 56- year-old man for whom we performed a complete tumor resection through median sternotomy. Microscopic examination revealed that the mass was primarily a low-grade, dedifferentiated liposarcoma, with a partial high-grade area. Occurrence of dedifferentiated liposarcoma in the anterior mediastinum is rare. We did not perform any adjuvant therapy. Three years after the surgery, the patient is alive without disease. In lipoma-like, well-differentiated liposarcoma cases, we should consider the possibility of dedifferentiated liposarcoma if a mild, atypical spindle cell component is found.     

Dedifferentiated chondrosarcoma arising in a solitary osteochondroma with leiomyosarcomatous component: a case report

BACKGROUND: A rare variant of dedifferentiated chondrosarcoma with leiomyosarcomatous component in a 63-year-old male is reported. CASE REPORT: He had a life-long osteochondroma adjacent to the left knee and recently developed swollen and pain. We initially suspected an intermediate grade chondrosarcoma arising in a solitary osteochondroma, but a biopsy specimen revealed a dedifferentiated component that histologically was classified as leiomyosarcoma. Multiple lung metastases were also present. The patient underwent amputation above knee and lung operation following adjuvant chemotherapy, but he died because of pulmonary metastasis 2 years after first admission. DISCUSSION: The differentiated component usually shows the histological features of osteosarcoma, malignant fibrous histiocytoma, and fibrosarcoma. Among the rare dedifferentiation with leiomyosarcomatous component, case arising in a solitary osteochondroma is not reported yet.     

Dedifferentiated chondrosarcoma of the thumb: a case report

Dedifferentiated chondrosarcoma (DDCS) comprises approximately 10% of all chondrosarcomas and has the worst outcome with 5-year survival of 10%. The preferred localizations are femur, humerus and pelvis. We report a case of DDCS that arose in proximal phalanx of left-hand thumb of a 66-year-old man. He was admitted with a 2-month history of pain and swelling in his thumb. He had experienced a fracture 15 years ago in the same localization with a history of suspected preexisting enchondroma. Plain radiographs showed an expansive osteolytic lesion with milimetric calcifications while magnetic resonance imaging revealed intraosseous focal globular hyperintense spots consistent with chondroid areas as well as a surrounding soft tissue mass with intermediate signal intensity. In biopsy specimen we observed a low-grade chondrosarcoma next to a spindle cell sarcoma with an abrupt transition. He was treated with amputation and died of the disease within 9 months following the surgery. The presence of dedifferented chondrosarcoma in bones of hands was not previously reported. The presented case was provided with the macroscopic and microscopic features observed in amputation specimen in comparison with radiological findings.     

Dedifferentiated Liposarcoma of the Pleura: Report of a Case

We report a case of dedifferentiated liposarcoma of the pleura in a 59-year-old man who presented with pain in the right chest wall, 3 years after a routine chest X-ray showed a large tumorous mass. The resected tumor was composed of three distinct histological features: well-differentiated liposarcoma with low-grade leiom-yosarcomatous and low-grade osteosarcomatous components. To our knowledge, this is the first report of dedifferentiated liposarcoma of the pleura.     

Dedifferentiated parosteal osteosarcoma with giant cell tumor component

Dedifferentiated parosteal osteosarcoma is characterized histologically by the admixture of low-grade fibroblastic osteosarcoma and a high-grade component typically resembling conventional osteosarcoma or malignant fibrous histiocytoma. We report an unusual distal femoral dedifferentiated parosteal osteosarcoma in which the dedifferentiated component resembled a giant cell tumor of bone. This phenotype is rarely described in the dedifferentiated component of a dedifferentiated parosteal osteosarcoma. The clinical, radiographic, and pathologic features of this unusual tumor are described to further expand the histologic spectrum of dedifferentiated parosteal osteosarcoma.     

3种方法诱导猪去分化脂肪细胞成肌分化效果的比较

目的 采用3种方法比较诱导猪去分化脂肪细胞（DA）成肌分化的效果，旨在筛选诱导猪DA成肌分化的较优方法。方法 采用糖皮质激素、半乳糖凝集素-1（galectin-1）法、5-氮胞苷（5-aza）分别诱导猪DA成肌分化，于培养6 d、15 d和21 d后，并分别用倒置显微镜观察分化的细胞形态；诱导21 d后用间接免疫荧光法检测成肌特异蛋白结蛋白（desmin）和肌球蛋白重链（MyHC）的表达，用Real-time PCR检测肌细胞生成素（MyoG） mRNA的表达,每种方法诱导3组，每组重复检测3次。 结果 诱导细胞的形态学观察显示，galectin-1法诱导的肌管形态最佳，多核细胞数量也最多；5-aza法次之，但诱导过程中细胞死亡率较高；糖皮质激素法诱导的细胞形态不规则，多形成放射状突起，而且出现较多成脂分化细胞。间接免疫荧光分析显示，galectin-1法和糖皮质激素法诱导的细胞Desmin、MyHC和MyoG mRNA都呈强阳性表达，而在5-aza法诱导的细胞这两种蛋白和基因都呈弱表达。 结论 从诱导细胞的肌管形态，分化的纯度，生存能力，特异蛋白和基因的表达量等综合判断，诱导猪DA成肌分化，galectin-1法优于糖皮质激素法和5-aza法。     

去分化肌肉干细胞神经增殖与分化能力的研究

目的研究和鉴定去分化肌肉干细胞是否具有神经增殖和分化能力。方法使用不同的条件性培养基,对去分化肌肉干细胞依次进行神经增殖和神经分化诱导,并通过形态学、免疫细胞荧光化学、反转录聚合酶链式反应(RT-PCR)等手段加以鉴定。结果①去分化肌肉干细胞在神经增殖培养基诱导下,形成典型神经球(neurospheres)结构,5-乙炔基-2’脱氧尿嘧啶核苷(EdU)标记阳性,抗巢蛋白(Nestin)阳性;RT-PCR提示肌形成蛋白(myogenin)表达水平下调,而Nestin、干细胞抗原-1(Sca-1)表达上调。②经神经分化培养基诱导,神经球细胞可分化为形态学上典型的、抗中间神经丝蛋白(NFm)阳性神经元。结论去分化肌肉干细胞具有神经增殖和分化潜能。     

Retroperitoneal dedifferentiated liposarcoma with osteosarcomatous components: a case report

We report a rare case of recurrent retroperitoneal dedifferentiated liposarcoma with osteosarcomatous components. An 82-year-old male diagnosed with recurrent retroperitoneal liposarcoma underwent a tumor resection. Histologically, osseous matrix with osteoid and mature hyaline cartilaginous tissues with high cellularity were observed in a fibrous background through most of the tumor, and scattered MDM2- and CDK4-positive atypical hyperchromatic stromal cells were detected surrounding the dedifferentiated areas. Dedifferentiation occurs in up to 10% of well-differentiated liposarcomas, frequently resembling a malignant fibrous histiocytoma-like pleomorphic sarcoma. In contrast, divergent differentiation with osteosarcomatous components is considered to be extremely rare.