Liposarcoma bien diferenciado con extensa metaplasia ósea y desdiferenciación osteosarcomatosa / Well-differentiated liposarcoma with extensive bone metaplasia and osteosarcomatous dedifferentiation

Dentro de la familia de los liposarcomas, el subtipo bien diferenciado es el más frecuente, caracterizado por su alta tendencia a la recaída local y ubicación retroperitoneal. La desdiferenciación ocurre en alrededor del 10% de los casos y habitualmente se manifiesta histológicamente como sarcoma pleomorfo de alto grado. La desdiferenciación heteróloga es un hecho que ocurre inhabitualmente. Presentamos un caso que debutó como un liposarcoma de bajo grado (lipoma like) que en su evolución tomografica muestra extensas áreas calcificadas y su histología confirma la trasformación a un sarcoma de alto grado con diferenciación osteosarcomatosa (AU)

Within the family of liposarcomas, the welldifferentiated subtype is the most frequent, characterized by its high tendency to local relapse and retroperitoneal localization. Dedifferentiation occurs in about 10% of cases and usually manifests histologically as high-grade pleomorphic sarcoma. Heterologous dedifferentiation is unusual. We present a case that debuted as a low grade liposarcoma (lipoma like) that in its tomographic evolution shows extensive calcified areas and its histology confirms the transformation to a high grade sarcoma with osteosarcomatous differentiation (AU)

Pathologic Fracture in Radiation-induced Osteosarcoma Misdiagnosed as Delayed Femoral Neck Fracture / 대한정형외과학회잡지

Secondary osteosarcoma has a relatively higher incidence in middle aged persons than in children. Radiation-induced osteosarcoma occurs in approximately 1% of patients who have been treated with more than 2,500 cGy. The time interval from radiation to onset of secondary osteosarcoma is approximately 10 to 15 years. A 51-year-old female who have been treated with radiation for angiomyxoma was hospitalized due to right hip pain. She had a minor trauma 2 weeks prior to hospitalization. A day before hospitalization, she experienced a second trauma by fall, and then, severe hip pain developed. A radiograph of the patient showed femoral neck fracture with sclerotic change of fractured margin. We diagnosed the patient as having a neglected femoral neck fracture and treated it with closed reduction using cannulated screw fixation. At 6 months post-surgery, the patient had residual pain of the right hip and we could find overproduced callus at the fracture site. Through further evaluation, we diagnosed this as secondary osteosarcoma with pulmonary metastasis. We report this case to make a warning about a misdiagnosed osteosarcoma as a simple femoral neck fracture.