Dedifferentiated giant-cell tumor of bone with an undifferentiated round cell mesenchymal component.

The dedifferentiated giant-cell tumor of the bone is a very rare variant of the giant-cell tumor (GCT). We report the clinical, radiographic and histological findings of a dedifferentiated GCT in which the dedifferentiated component consisted of small round cells. We also comment on previously reported cases of dedifferentiated GCT, discuss the clinical implications of this dual histology, and analyze the information published about the coexistence of similar genetic abnormalities in GCT and small round cell tumors of the bone.

[Bone tumor frequency in adults and elderly]. / Frecuencia de neoplasias óseas en adultos maduros y adultos mayores.

INTRODUCTION: We consider of great importance knowing the types of bone tumors and tumor-like lesions in adults and the elderly, which are increasing in proportion in our country. OBJECTIVES: (1) To analyze the frequency of bone tumors and tumor-like lesions in adults and elderly; (2) to determine any difference between these two groups; (3) and to analyze the most frequent sites of involvement. MATERIAL AND METHODS: We conducted a cross-sectional descriptive study that consisted in a retrolective review of all cases classified as a bone tumor or a tumorlike condition from year 2000-2006. We included all patients that presented with a bone tumor or tumor-like condition above 40 years-old. RESULTS: The most frequent diagnoses in patients between 40 and 60 years-old were plasmocytoma/myeloma (19.4%); giant cell tumor (14.1%) and metastases (12.3%). In patients older than 60 years, prevalence of bone tumor and tumor-like lesion was respectively: metastases (37.2%); plasmocytoma/myeloma (11.8%) and malignant fibrous histiocytoma (6.7%). Several differences were observed between these two groups.

Accuracy of intraoperative consultation for bone tumors: experience in an orthopedic hospital.

BACKGROUND: Intraoperative consultation is an integral part of surgical pathology. However, there are few reports concerning intraoperative pathology consultation exclusively for bone tumors. METHOD: Our hospital is an orthopedic institution that specializes in the diagnosis and treatment of bone tumors, and we retrospectively reviewed the intraoperative consultations for bone tumors on our service from January 2002 to February 2006. The objectives of this work were to: (1) evaluate the clinical reasons for intraoperative consultation on bone tumors; (2) identify discordant diagnoses between the intraoperative consultation diagnosis and the definitive diagnosis; (3) determine in how many cases it was possible to establish a specific diagnosis; and (4) analyze the accuracy of the intraoperative consultation diagnosis on the bone tumors. RESULTS: The two most common reasons for an intraoperative consultation were to rule out malignancy and to determine the adequacy of the resection margins. The third most common reason was to establish a diagnosis. In the latter cases, it was possible to establish a specific diagnosis in 86.3% of the cases; and we had only one discordant case. CONCLUSIONS: Intraoperative consultation on bone tumors has problems and limitations. They are due mainly to the characteristics of the material that comprise the specimen from this type of lesion. It is important that similar assays be carried out at medical institutions that specialized in bone tumors to determine the effectiveness rates of intraoperative consultation in this field throughout the world. This is the first series that has analyzed the accuracy of intraoperative consultation on bone tumors with respect to the clinical reasons for the consultation.

Fine needle aspiration cytology of low grade fibromyxoid sarcoma. Report of a case with histologic correlation.

BACKGROUND: Low grade fibromyxoid sarcoma, first described in 1987, is a rare sarcoma characterized by a bland and deceptively benign histologic appearance but with aggressive behavior. CASE: A 51-year-old female presented with a history of a recurrent and slowly growing mass in the left foot. Fine needle aspiration biopsy showed an abundant myxoid background with occasional thick bands of collagen. Tumor cells present in the myxoid background were spindle shaped, with focally mild or a light degree of nuclear enlargement, hyperchromasia and pleomorphism CONCLUSION: Low grade fibromyxoid sarcoma has particular cytologic features. Besides a careful cytologic evaluation of all the components, clinical and radiographic correlation is necessary to make the correct diagnosis.

Efecto de la metilprednisolona en la amibiasis hepática experimental / Effect of methylprednisolone in experimental amebic liver abscess

Para examinar si la extensión de la necrosis tisular en la amibiasis hepática experimental en hamsters es proporcional a la magnitud de la respuesta inflamatoria inicial se comparó la evolución morfológica de las lesiones en presencia y en ausencia de dosis altas de metilprednisolona a las 10 hrs, 24 hrs, 72 hrs y 7 días. Se observó en los animales con metilprednisolona una respuesta inflamatoria inicial menor que en los controles y una extensión de las lesiones menor a los 7 días de evolución. La metilprednisolona no altera ni la actividad proteolítica ni la eritrofagocitosis de Entamoeba histolytica in vitro.