Low-grade central osteosarcoma of the skull

Low-grade central osteosarcoma in proximal humerus: a rare entity

Low-grade central osteosarcoma is a rare subtype of tumor with low-grade malignancy. Currently, wide resection with negative resection margin is the standard treatment for this disease. The role of neoadjuvant chemotherapy in low-grade central osteosarcoma was controversial and was mostly considered for tumors containing high-grade focal areas. Local tumor recurrences often exhibited a tumor with higher histologic grade or differentiation with the potential for metastases. In low-grade central osteosarcoma, timely wide resection after definite diagnosis can result in 5-year survival for almost 90%. However, the relatively nonspecific radiological and pathological findings make diagnosis very difficult. MDM2 and CDK4 are specific and provide sensitive markers for the diagnosis of low-grade central osteosarcoma, helping to differentiate low-grade central osteosarcoma from some benign lesions, including fibrous dysplasia, bone giant cell tumor, and chondrosarcoma. Here, we report the case of a 19-year-old woman with low-grade central osteosarcoma located at the proximal humerus. The affected site was rare, but the sensitive biomarkers CDK4 and MDM2 were positive. The patient recovered well after wide tumor resection following a proximal humerus endoprosthesis replacement. Our case highlighted the management strategies in low-grade central osteosarcoma. Being familiar with radiographic features, understanding the biological characteristics, and mastering diagnostic biomarkers can help oncologists avoid embarrassing situations in treatment when this rare tumor is highly suspected, even when located at an uncommon site. The discussion in this report focuses on radiographic and pathological features, advances of biomarkers that help in differential diagnosis, and current treatment options in low-grade central osteosarcoma.

Primary osteosarcoma of the cranial vault

Only 5-10% of osteosarcomas arise from the craniofacial bones. We report the case of a 14-year-old female patient who presented with headache and a mass that had been growing in the left frontoparietal region for six months. We describe the findings on conventional radiography, computed tomography, and magnetic resonance imaging.

Low-grade central osteosarcoma of the orbit

Low-grade central osteosarcoma is a rare type of osteosarcoma, representing fewer than 2% of all osteosarcomas. Approximately 80% of these tumors are located in the long bones, and they are particularly common in the distal and proximal tibia. However, they are rare in the craniofacial bones, and this tumor type has never been reported to occur in the orbit. In this report, a case of low-grade central osteosarcoma arising from the orbit is presented. The differential diagnoses of this tumor and the surgical results of radical resection and reconstruction are also presented.

Low-grade central osteosarcoma of the mandible: a case study report

Low-grade central osteosarcoma is a rare type of osteosarcoma with peculiar clinical radiographic and microscopic features. The aim of this article is to report and discuss a case of low-grade central osteosarcoma in the mandible of a 42-year-old woman. The patient reported sensing mild pain and tooth mobility for a period of 4 years, despite continuous dental treatment. Radiographic evaluation showed a mixed radiopaque/radiolucenct lesion in the body, ramus, coronoid process, and condyle of the left side of the mandible. Destruction of the mandibular cortex in the area was also observed. After incisional biopsy, the patient underwent hemimandibulectomy. Microscopic findings showed a tumor exhibiting spindle cells with nuclear hyperchromasia and no mitotic activity, irregular osteoid formation, and soft tissue infiltration. The immunohistochemical analysis of the expression of Ki-67, Cyclin B1, and PCNA proteins (cellular proliferation markers) revealed a very low Ki-67+ and Cyclin B1+ cell index (mean 7% and 3%, respectively), but a moderate number of PCNA+ cells (mean 49%). The 2 years of clinical and imaging postoperative follow-up showed no evidence of recurrence. Clinicians should be aware of these lesions, because histopathologicially low-grade central osteosarcoma may be misinterpreted as fibrous dysplasia.