Telangiectatic osteosarcoma (TOS) is a rare variant of osteosarcoma that typically affects young individuals and long bones. The case under discussion was seen in the mandible of a 57-year-old female and had rapidly grown in size within a week. Microscopically, the tumour was characterised by large vascular cavities surrounded by anaplastic cells. Thin lacy tumour osteoid was observed at various foci. Abundant multinucleated osteoclastic giant cells along with areas of necrosis were also noted. The tumour cells were positive for SATB2, while negative for Cytokeratin AE1/3, CD 34. Ki-67 positivity was observed in more than 50% of tumour cells. A diagnosis of high grade telangiectatic osteosarcoma was thus made.

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UNASSIGNED: Telangiectatic osteosarcoma (TOS) is a rare but highly malignant subtype of osteosarcoma. Although surgical treatment is the primary treatment modality for osteosarcoma, evidence on the benefits of different surgical methods in patients with TOS is lacking. This study aimed to compare the effects of different surgical and adjuvant treatments on overall survival of TOS, and the association of patient demographics, oncological characteristics, and socioeconomic status on treatment outcomes.
UNASSIGNED: This retrospective study selected the most common TOS cases of the extremities registered in the Surveillance, Epidemiology, and End Results (SEER) database from 1989 to 2019. Univariate and multivariate Cox regression models were used to analyze all prognostic factors, and Kaplan-Meier analyses were performed for disease-specific treatment factors of survival.
UNASSIGNED: A total of 127 patients were included in the analysis. The average age at initial diagnosis was 20.09 years. In univariate analyses, the absence of metastasis at initial diagnosis, limb-salvage surgery, adjuvant chemotherapy, and no regional lymph node dissection were associated with a lower risk of death. Multivariate analysis further showed that the presence or absence of distant metastasis and regional lymph node dissection, implementation of adjuvant chemotherapy, and choice of surgical method were independent predictors of prognosis.
UNASSIGNED: Distant metastasis and regional lymph node dissection are associated with poorer outcomes in TOS, and amputation has no better prognosis than limb salvage surgery. Compared with conventional chemotherapy, neoadjuvant chemotherapy did not significantly improve the prognosis of TOS.

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.

Telangiectatic osteosarcoma (TOS) is a subtype of osteosarcoma. TOS in the elderly and TOS in the skull are very rare. Here, we report a case of TOS in the frontal bone of an elderly patient. The patient was a 79-year-old woman who was identified as having a right frontal bone lesion. The patient was initially diagnosed with an intradiploic epidermoid cyst (IEC). A 60mm cystic lesion with bone destruction appeared 5 years later, which enlarged over 2 months. The fluid in the cyst seemed to be blood that had lost its clotting ability. Tumor and the surrounding tissue were resected. The postoperative course was favorable. Postoperative magnetic resonance imaging (MRI) showed no evidence of residual lesions. There was no metastases. Histopathologically, the cyst wall was composed of fibrous connective tissue and did not contain epithelial components. There were no skin appendages and keratinized tissues in the lesion. Based on these findings, the diagnosis changed to aneurysmal bone cyst (ABC). Subsequent immunohistochemical examinations confirmed that the MIB-1 index was 50% in some sections and there were atypical cells showing osteogenic properties in other sections. Based on these results, the patient was finally diagnosed with TOS. The differential diagnoses for cystic lesion presenting bone destruction include TOS, ABC, and IEC. In case of cystic lesion with bone destruction, early diagnosis based on histopathological study is important and complete resection with surrounding tissues is required, given the possibility of TOS.

Telangiectatic osteosarcoma (TOS) is an aggressive variant of osteosarcoma (OS) with distinctive radiographic, gross, microscopic features, and prognostic implications. Despite several studies on OS, we are still far from understanding the molecular mechanisms of TOS. In recent years, many studies have demonstrated not only that microRNAs (miRNAs) are involved in OS tumorigenesis, development, and metastasis, but also that the presence in high-grade types of OS of cancer stem cells (CSCs) plays an important role in tumor progression. Despite these findings, nothing has been described previously about the expression of miRNAs and the presence of CSCs in human TOS. Therefore, we have isolated/characterized a putative CSC cell line from human TOS (TOS-CSCs) and evaluated the expression levels of several miRNAs in TOS-CSCs using real-time quantitative assays. We show, for the first time, the existence of CSCs in human TOS, highlighting the in vitro establishment of this unique stabilized cell line and an identification of a preliminary expression of the miRNA profile, characteristic of TOS-CSCs. These findings represent an important step in the study of the biology of one of the most aggressive variants of OS and the role of miRNAs in TOS-CSC behavior.

Aneurysmal bone cyst (ABC) is a benign locally aggressive tumor that occurs in childhood and early adulthood. Most relevant differential diagnoses are the telangiectatic osteosarcoma and the giant cell tumor. In the present case series chemotherapy following the EURAMOS or the Euro-Ewing 99 protocol was externally applied in three patients with the misdiagnosis of ABC as malignant bone tumor. In all three cases, a significant reduction of the volume of the ABC was achieved. This is the first report about the use of neoadjuvant chemotherapy in ABC. Chemotherapy reduces the size of an ABC and leads to progressive sclerosis.

OBJECTIVE: Aneurysmal bone cyst (ABC) and telangiectatic osteosarcoma (TOS) share several clinical and imaging features, including young presentation, long bone involvement, lytic appearance on radiography and fluid-fluid levels on MRI. Therefore, they may be difficult to differentiate. The aim of this study is to identify clinical, radiological and MRI features which aid differentiation of the two lesions.
METHODS: Retrospective review of all histologically confirmed ABC and TOS over an 11-year period. Data recorded include age at presentation, sex, skeletal location and various radiographic and MRI features.
RESULTS: This retrospective study included 183 patients, 92 males and 91 females. Mean age at presentation of 18.4 years (range 1-70 years); 152 cases of ABC and 31 TOS. No significant difference between age and sex. TOS was significantly less likely to involve the axial skeleton; no difference related to location within the bone. Radiographic findings significantly favouring ABC included a less aggressive pattern of bone destruction, a purely lytic appearance, an expanded but intact cortex, no periosteal response and no soft tissue mass. MRI features significantly favouring ABC included smaller tumour size (maximum mean dimension 46 mm compared to 95 mm for TOS), absence of soft tissue mass, > 2/3 of the lesion filled with fluid levels and thin septal enhancement following contrast.
CONCLUSIONS: Several radiographic and MRI features aid in the differentiation between ABC and TOS. Lesions with a geographic Type 1A or IB pattern of bone destruction which are completely filled with FFLs on MRI can confidently be diagnosed as ABC.

UNASSIGNED: We intend to analyze the gain and loss from transcatheter intra-arterial (IA) limb infusion of cisplatin for extremity osteosarcoma in the past six years.
UNASSIGNED: Between December 2009 and August 2014, a total of 99 patients were analyzed for efficiency and followed up for long-term survival. Based on the different administration methods of cisplatin, we divided them into the following two cohorts: IA infusion of cisplatin (n=48) and intravenous (IV) infusion of cisplatin (n=51). Except for cisplatin, all the other drugs were given intravenously. Cisplatin was given intra-arterially with an infusion time of 3 hrs or 6 hrs using a pump, whereas historical controls received IV infusion of cisplatin within 60 mins. Tumor neovascularity (TNV) was analyzed before infusion, and subsequent arteriograms were compared with the baseline to determine percent changes. Definitive surgery with intended wide resection and postoperative pathological evaluation were performed in all these patients.
UNASSIGNED: No local or overall survival benefit was found in the patients preoperatively treated with IA infusion of cisplatin compared with IV infusion (P=0.336 and 0.173, respectively). Furthermore, serial arteriography was used to predict a good histologic response with an accuracy of 73.1% and a sensitivity of 100%. There were sporadic cases with the telangiectatic subtype, which did not respond very well to IV chemotherapy, but later, the tumor obviously shrank after IA infusion of cisplatin. Our study also showed that the rates of the complication of skin and muscle necrosis were not so low as reported.
UNASSIGNED: We did not observe any survival advantage of chemotherapy using IA infusion in osteosarcoma of the extremities. Arteriography for TNV can be used to predict the tumor histologic response. Malposition of the catheter might severely increase the complication of skin or muscle necrosis.