1/15. Large cell, epithelioid, telangiectatic osteoblastoma: a unique pseudosarcomatous variant of osteoblastoma.A previously undescribed large-cell, epithelioid, and aneurysmal variant of osteoblastoma with minimal osteoid-production--simulating telangiectatic osteosarcoma, epithelioid angiosarcoma, and metastatic carcinoma is reported. The tumor occurred in the mandible of a 14-year-old girl. The light microscopic, immunohistochemical, ultrastructural, cell proliferation, and dna-ploidy studies, as well as the 7-year disease-free follow-up period all indicate a benign osteoblastic tumor. Cytogenetically, the tumor had a pseudodiploid karyotype, distinguished by a complex t(1;5;17;22) and a terminal 1q deletion. Recognition of this unique, pseudomalignant variant of osteoblastoma is important to avoid an erroneous diagnosis of malignancy.- - - - - - - - - - ranking = 1keywords = osteosarcoma (Clic here for more details about this article) |
2/15. Periosteal osteoblastoma: a case report and a review of the literature.Osteoblastomas located on the surface of cortical bone, so-called periosteal (juxtacortical) osteoblastomas, are extremely rare. A 24-year-old man complained of pain and swelling in the left knee. The clinical and radiological investigation showed a tumor located in the posterior portion of the distal shaft of the femur. The radiological differential diagnosis included parosteal osteosarcoma, periosteal chondroma and periostitis ossificans. A frozen section was obtained and histology revealed an osteoblastoma with large epithelioid-appearing osteoblasts consistent with an aggressive osteoblastoma. An en bloc resection of the tumor was performed and the definitive histology of the whole specimen revealed a typical osteoblastoma. The authors draw attention to the fact that periosteal osteoblastoma is a rare tumor that could be mistaken clinically and histologically for other and more common tumors at this location.- - - - - - - - - - ranking = 1keywords = osteosarcoma (Clic here for more details about this article) |
3/15. osteoblastoma-like osteosarcoma.We report an osteoblastoma-like osteosarcoma in the right proximal fibula in a 22-year-old woman. Radiographs showed an irregular osteolytic lesion from the metaphysis to the epiphysis in the proximal fibula with partial destruction of cortical bone. Tissue from a biopsy indicated a typical osteoblastoma. curettage and bone graft was performed. One year after the surgery, local recurrence occurred, and a wide excision was performed. Histological examination of the en-bloc surgical specimen revealed the tumor had permeated through the host bony trabeculae, although the nuclear atypia was not marked. Immunohistochemical expression of MIB-1 was detected in 9.0% of cells.- - - - - - - - - - ranking = 5keywords = osteosarcoma (Clic here for more details about this article) |
4/15. Aggressive osteoblastoma of the mandible closely simulating calcifying epithelial odontogenic tumor. Report of two cases with unusual histopathologic findings.Aggressive osteoblastoma is a rare bone-forming neoplasm composed of prominent epithelioid cells that demonstrate locally invasive growth with a high rate of recurrence but no metastatic potential. Clinical, radiographic and pathologic features of mandibular aggressive osteoblastoma in a 21-year-old African-American male and a 12-year-old Caucasian female are presented. Both tumors were resected with wide surgical margins and neither patient had adjuvant radiation or chemotherapy. The patients showed no evidence of local recurrence or distant spread either clinically or radiographically after two years of follow-up. These tumors were composed of solid sheets of pleomorphic epithelioid cells, eosinophilic amorphous osteoid with foci of calcification, which closely simulated amyloid. Differentiation of this tumor from histologically similar calcifying epithelial odontogenic tumor and low-grade osteosarcoma proved difficult. Immunohistochemical study with osteocalcin confirmed the osteoblastic nature of these epithelioid cells.- - - - - - - - - - ranking = 1keywords = osteosarcoma (Clic here for more details about this article) |
5/15. osteoblastoma-like osteosarcoma of the distal tibia.We report a case of a 14-year-old boy with an intracompartmental lytic lesion with poorly defined margins in the right distal tibia that was originally treated with curettage and bone grafting. Histologic examination showed an osteoblastic tumor with unusual features, which was found on consultation to be an osteoblastoma-like osteosarcoma, a rare, low-grade variant of osteosarcoma. Subsequently, the patient underwent en bloc resection of the distal tibia, which was replaced with vascularized bone graft and followed by chemotherapy. Two years later, he is alive with lung metastases.- - - - - - - - - - ranking = 6keywords = osteosarcoma (Clic here for more details about this article) |
6/15. Epiphyseal osteoblastoma-like osteosarcoma.osteoblastoma-like osteosarcoma is a rare variant of osteosarcoma occurring in this instance in a highly unusual location: the lateral femoral condyle of a 13-year-old girl. The radiological features were non-aggressive and, although slightly unusual, were most suggestive of chondroblastoma.- - - - - - - - - - ranking = 6keywords = osteosarcoma (Clic here for more details about this article) |
7/15. Periosteal osteoblastoma of the distal femur.Osteoblastomas located on the surface of the cortical bone, so-called periosteal osteoblastomas, are extremely rare. We report on a case of periosteal osteoblastoma arising from the posterior surface of the right distal femur in a 17-year-old man. Roentgenographic, computed tomographic, magnetic resonance imaging, and histologic features of the case are presented. Periosteal osteoblastoma should be radiologically and histologically differentiated from myositis ossificans, avulsive cortical irregularity syndrome, osteoid osteoma, parosteal osteosarcoma, periosteal osteosarcoma, and high-grade surface osteosarcoma. Although periosteal osteoblastoma is rare, this tumor should be included in the differential diagnosis of surface-type bone tumors.- - - - - - - - - - ranking = 3keywords = osteosarcoma (Clic here for more details about this article) |
8/15. A rare case of periosteal osteoblastoma located in the frontal cranial bone.Periosteal osteoblastoma is an extremely rare bone-forming neoplasm located on the surface of cortical bone. Of the fewer than 30 cases of periosteal osteoblastomas found in the literature, 2 have been reported to be located in cranial bone, and these have not been documented in detail with clinical history, radiographic findings, macroscopic features, and microscopic findings. Although the differential diagnoses of periosteal lesions include parosteal and periosteal osteosarcoma, periosteal chondroma and chondrosarcoma, osteochondroma, osteoid osteoma, periostitis ossificans, and myositis ossificans, an important differential diagnosis both radiologically and pathologically of such a lesion in the cranium is meningioma. We report an unusual case of periosteal osteoblastoma located in the frontal cranial bone that was radiologically consistent with a meningioma. The differential diagnosis of metaplastic meningioma with differentiation toward bone is discussed.- - - - - - - - - - ranking = 1keywords = osteosarcoma (Clic here for more details about this article) |
9/15. Osteoblastic osteosarcoma of the mandible: findings on Tc-99m HMDP bone and Ga-67 citrate scintigraphy.A 25-year-old woman presented with a disturbance in the opening of her mouth 5 months before admission. On admission, painful swelling of the right preauricular region was revealed. Computed tomography (CT) demonstrated a soft tissue density mass around the right condylar process of the mandible. Tc-99m hydroxymethylene diphosphonate (HMDP) bone scintigraphy and Ga-67 citrate scintigraphy showed avid uptake in the mass. The tumor was histologically identified as an osteoblastic osteosarcoma of the right mandible. There are few reports of Ga-67 citrate scintigraphy findings of osteoblastic osteosarcoma of the mandible. The accumulation patterns on Tc-99m HMDP bone scintigraphy and Ga-67 citrate scintigraphy are possibly characteristic of osteoblastic osteosarcoma of the mandible.- - - - - - - - - - ranking = 7keywords = osteosarcoma (Clic here for more details about this article) |
10/15. osteoblastoma of the scaphoid: a case report.osteoblastoma is an uncommon primary bone tumor that rarely is found in the hand or wrist. Recurrent osteoblastomas often have a more aggressive appearance than the original tumor, and differential diagnosis from osteosarcoma is difficult. The pain that can accompany this tumor is debilitating. Therefore, successful treatment requires complete removal of the tumor. The purpose of this report is to present an unusual case of osteoblastoma of the carpal scaphoid. This tumor was treated successfully by curettage and bone grafting. At 1 year postoperatively, the patient presented with a stable, painless wrist with full range of motion.- - - - - - - - - - ranking = 1keywords = osteosarcoma (Clic here for more details about this article) |
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