UNASSIGNED: Osteosarcoma (OS) is one of the most common primary malignant bone tumors in children and adolescents. OS incidence varies significantly with age and peak incidence is in adolescent age group. Telangiectatic osteosarcoma (TOS) is an unusual variant of OS, forming 3-10% of all OSs. Only few case reports of this rare variant of OS are described in the literature.
UNASSIGNED: We report a 6-year-girl who presented with fracture of the left proximal humerus after a trivial trauma. X-ray left shoulder showed osteolytic lesions in the left proximal humerus with fracture of proximal humerus. Open biopsy from the left proximal humerus osteolytic lesion suggested clusters of highly atypical cells like osteoid material and focal areas of hemorrhage and necrosis suggestive of TOS. The child was started on chemotherapy followed by limb-salvage surgery with wide resection of the tumor in the left proximal humerus. She completed her adjuvant chemotherapy and is currently doing well for the past 4 years.
UNASSIGNED: OS occurs more frequently in adolescents around the knee in the metaphyses. The most common histologic type is osteoblastic/fibroblastic or chondroblastic type. Very few cases have been reported in <5 years age group and it\'s relatively rare in 5-10-year-old children. Rare histologic variants, especially telangiectatic variant, are more common in younger children and occur more in upper limbs. Imaging reveals mainly osteolytic lesions, unlike in conventional OS. This case highlights the utmost role of histopathology in the diagnosis of the bone tumors which would guide the management appropriately.

Osteosarcomas arising in the epiphysis are extremely rare and easily missed in the diagnostic consideration of epiphyseal tumors. It is the purpose of this study to delineate the clinical pathological characteristics of \'epiphyseal osteosarcoma\' under the definition of \'a solitary long bone osteosarcoma radiographically considered an epiphyseal tumor for which the main radiologic differential diagnosis would encompass giant cell tumor, chondroblastoma and clear cell chondrosarcoma\'. Four such cases with unusual histopathology were retrieved among 110 cases of osteosarcoma. Their clinical, radiological and pathological features, together with all 10 reported cases, were analyzed. The radiographic diagnoses of our four cases include two giant cell tumors, one chondroblastoma and one clear cell chondrosarcoma but turn out to be fibroblastic, giant cell rich, telangiectatic and epithelioid variant of epiphyseal osteosarcoma. Including our patients, the 14 reported epiphyseal osteosarcomas comprise 8 males and 6 females, the age at presentation ranges from 11 to 39 years, two-third in the second decade, 71.4% affect the femur. Due to their epiphyseal locations, many carry benign radiological diagnoses notably giant cell tumor and chondroblastoma. Epiphyseal osteosarcomas may not only masquerade as benign radiological bony lesions but also assume many histological patterns; orthopedic surgeons, radiologists and pathologists should be aware of such possibility. Their behavior and prognosis are dictated by the histologic types, grading and staging rather than location.

Telangiectatic osteosarcoma is a rare variant of osteosarcoma and hence its occurrence, presentation, and prognosis are poorly understood. With advancements in technology and available treatment options, the scenario of its diagnosis, management, and outcome has changed. Chemotherapy with surgery was challenged previously, but has now been proved to be beneficial. We reviewed the available literature and compared results to define the characteristics of the disease, its presentation, radiographic and pathologic features, optimal treatment, and prognosis.