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Osteosarcoma (OS) is the most common primary malignant bone tumour in children and young adults. Account for 80% of all OS cases, conventional OS are characterized by the presence of osteoblastic, chondroblastic and fibroblastic cell types. Despite this heterogeneity, therapeutic treatment and prognosis of OS are essentially the same for all OS subtypes. Here, we report that DEC2, a transcriptional repressor, is expressed at higher levels in chondroblastic OS compared with osteoblastic OS. This difference suggests that DEC2 is disproportionately involved in the progression of chondroblastic OS, and thus, DEC2 may represent a possible molecular target for treating this type of OS. In the human chondroblastic‐like OS cell line MNNG/HOS, we found that overexpression of DEC2 affects the proliferation of the cells by activating the VEGFC/VEGFR2 signalling pathway. Enhanced expression of DEC2 increased VEGFR2 expression, as well as increased the phosphorylation levels at sites Y951 and Y1175 of VEGFR2. On the one hand, activation of VEGFR2Y1175 enhanced cell proliferation through VEGFR2Y1175‐PLCγ1‐PKC‐SPHK‐MEK‐ERK signalling. On the other hand, activation of VEGFR2Y951 decreased mitochondria‐dependent apoptosis rate through VEGFR2Y951‐VARP‐PI3K‐AKT signalling. Activation of these two signalling pathways resulted in enhanced progression of chondroblastic OS. In conclusion, DEC2 plays a pivotal role in cell proliferation and apoptosis‐resistance in chondroblastic OS via the VEGFC/VEGFR2 signalling pathway. These findings lay the groundwork for developing focused treatments that target specific types of OS. [ABSTRACT FROM AUTHOR]

Chondroblastic osteosarcoma of the nasal cavity is a rare and aggressive tumor that presents diagnostic challenges due to its variable clinical and radiological features. Histological analysis is crucial for an accurate diagnosis, despite morphological similarities with chondrosarcoma. We present a case of primary craniofacial chondroblastic osteosarcoma originating from the nasal cavity in a 17-year-old adolescent. The tumor was characterized by cartilaginous lobules and spindle cell proliferation with osteoid matrix deposition. Immunohistochemical analysis supported the diagnosis. This case highlights the rarity of this particular presentation and emphasizes the significance of accurate diagnosis through histopathological evaluation to achieve optimal management. [ABSTRACT FROM AUTHOR]

Abstract Background Mandible can be the site of benign or malignant lesions of different origins, including odontogenic and non-odontogenic lesions. Cartilage-forming tumors have been rarely reported at this site. Chondrosarcoma is a rare malignant cartilage-producing neoplasm that is extremely rare in the mandible. The rarity of cartilage-forming tumor occurrence in the mandible can make diagnosis difficult for pathologists, as they do not expect this type of tumor at this anatomical site. Here we report a case of chondrosarcoma of mandibular angle. Case presentation A 70-year-old Moroccan male patient consulted a dentist for wisdom tooth pain. Wisdom tooth extraction was conducted. After 6 months, the patient reported the recurrence of pain associated with swelling in the mandibular area and paresthesia along the path of the mandibular nerve. A panoramic radiograph demonstrated a mixed radiolucent–opaque lesion involving the mandibular angle. Computed tomography showed a large osteolytic spontaneously hypointense and multilobulated lesion. A biopsy was done. Histopathological examination revealed sheets and irregular lobules of atypical cells presenting cartilaginous differentiation. Tumor cells showed severe nuclear atypia and were located within a hyaline cartilage matrix. Some foci of necrosis were noted. Osteoid deposits were not found. The patient was diagnosed with grade III chondrosarcoma and underwent a right segmental mandibulectomy with submandibular lymph node dissection. Macroscopically, the tumor was localized in the mandibular angle with extension in the mandibular body. Histopathology confirmed the previous diagnosis of grade III chondrosarcoma and did not show any lymph node metastasis. Conclusions Owing to many histological similarities, grade III chondrosarcoma must be distinguished from chondroblastic osteosarcoma and metastatic lesions. In addition, chondroblastic osteosarcoma of the jawbones has a worse prognosis than chondrosarcoma, making the distinction between these two malignant tumors the most important concern of the pathologist when dealing with a cartilage-forming tumor at this site. Surgery with wide excision margins remains the best therapeutic approach, while the role of radiotherapy is controversial. The management of mandibular chondrosarcoma requires a multidisciplinary approach involving maxillofacial surgeons, radiologists, pathologists, and oncologists.

Purpose: Describe clinical characteristics and outcome of Li-Fraumeni syndrome (LFS)-associated osteosarcomas., Methods: TP53 germline pathogenic/likely pathogenic variant carriers diagnosed with osteosarcoma in France between 1980 and 2019 were identified via the French Li-Fraumeni database at Rouen University Hospital. Sixty-five osteosarcomas in 52 patients with available clinical and histological data were included. The main clinical characteristics were compared with data from National Cancer Institute's SEER (Surveillance, Epidemiology, and End Results) for patients of the same age group., Results: Median age at first osteosarcoma diagnosis was 13.7 years (range: 5.9-36.7). Compared to unselected osteosarcomas, LFS-associated osteosarcomas occurred more frequently in patients less than 10 years of age (23% vs. 9%), and when compared with osteosarcomas in patients less than 25 years were characterized by an excess of axial (16% vs. 10%) and jaw sites (15% vs. 3%) and histology with predominant chondroblastic component and periosteal subtypes (17% vs. 1%). Metastases incidence (25%) was as expected in osteosarcomas. After the first osteosarcoma treatment, the rate of good histologic response (62%) and the 5-year progression-free survival (55%, 95% confidence interval [CI]: 42.6-71.1) were as expected in unselected series of osteosarcomas, whereas the 5-year event-free survival was 36.5% [95% CI: 25.3-52.7] due to the high incidence of second malignancies reaching a 10-year cumulative risk of 43.4% [95% CI: 28.5-57.5]., Conclusion: In osteosarcoma, young age at diagnosis, axial and jaw sites, histology with periosteal or chondroblastic subtype, and synchronous multifocal tumors should prompt suspicion of a germline TP53 mutation. Standard treatments are effective, but multiple malignancies impair prognosis. Early recognition of these patients is crucial for tailored therapy and follow-up., (© 2024 The Author(s). Pediatric Blood & Cancer published by Wiley Periodicals LLC.)

Background: Osteosarcoma is a primary bone malignancy occurring due to abnormal proliferation of bone forming mesenchymal cells. Chondroblastic Osteosarcoma is a rare variant of osteosarcoma which is associated with higher recurrence rate and metastatic potential. Case report: A 21 year old lady had complaints of pain in her left thigh for one year. On examination, a hard mass was palpable over the lateral aspect of the distal thigh. Radiographs revealed an ill-defined ‘fluffy’ osseous lesion involving the metaphyseal region of distal femur, and extending into the soft tissue. Computed tomography (CT) scan showed mixed lytic and blastic regions. CT guided core needle biopsy was performed. Histopathological examination showed a cellular lesion with chondroblastic differentiation and focal lace like osteoid formation. Immunohistochemistry confirmed the diagnosis of Chondroblastic Osteosarcoma. Two cycles of neoadjuvant chemotherapy was given, after which wide resection of the tumor and reconstruction of distal thigh, knee joint and proximal tibia with modular megaprosthesis was done. At 5 years follow up, she showed no evidence of recurrence, and was noted to have an excellent Musculoskeletal Tumor Society (MSTS) Score of 26. Conclusion: Chondroblastic Osteosarcoma is a rare variant of osteosarcoma which can be distinguished from classical osteosarcoma by histopathology. It is important to recognise this variant as it is associated with a higher recurrence rate and metastatic potential. Limb salvage surgery with megaprosthesis provided excellent functional outcome with no recurrence in our case.

Development of bone tumors as a result of chronic osteomyelitis represents a relatively rare and late complication in humans and animals. We described a malignant transformation (chondroblastic osteosarcoma) in a 7-year-old German shepherd with a history of polyostotic osteomyelitis caused by Serratia liquefaciens when the dog was 15 months old. The tumor developed in the right humeral diaphysis, one of the sites of polyostotic osteomyelitis. To the best of our knowledge this is the first report of polyostotic osteomyelitis caused by Serratia liquefaciens in dogs. [ABSTRACT FROM AUTHOR]

Abstract In patients presenting to the operating room with a saddle pulmonary embolism for noncardiac surgery, it is best to take a multidisciplinary approach and involve the cardiac and vascular surgeons.

The management of osteosarcoma in children and adolescents is based on poly-chemotherapy including several nephrotoxic drugs (e.g. ifosfamide, methotrexate, and cisplatinum). Chronic renal toxicity is a frequent complication but stage 5 chronic kidney disease requiring dialysis is rare. We report here a series of six pediatric patients with osteosarcoma displaying chronic kidney disease after chemotherapy. We retrospectively reviewed the medical charts, mainly for clinical history, timing between chemotherapy and development of tubulopathy and CKD, type of therapies and global evolution (chronic dialysis and further renal transplantation, n = 2; death, n = 1). Notably, all patients suffered from chondroblastic osteosarcoma. Advanced chronic kidney disease can be a complication of osteosarcoma management that could more frequently lead to dialysis and further transplantation. It would be interesting to identify specific risk factors of such renal toxicity. The chondroblastic sub-type may be associated with such susceptibility, but this needs to be confirmed. [ABSTRACT FROM AUTHOR]

Chondrosarcomas of the spine are rare tumors and represent

Development of bone tumors as a result of chronic osteomyelitis represents a relatively rare and late complication in humans and animals. We described a malignant transformation (chondroblastic osteosarcoma) in a 7-year-old German shepherd with a history of polyostotic osteomyelitis caused by Serratia liquefaciens when the dog was 15 months old. The tumor developed in the right humeral diaphysis, one of the sites of polyostotic osteomyelitis. To the best of our knowledge this is the first report of polyostotic osteomyelitis caused by Serratia liquefaciens in dogs.

Osteosarcoma (OS) is a malignant tumor that induces formation of osteoid or immature bone and rarely occurs in maxilla. Maxillofacial OSs are reported to occur in the third to fifth decades that is 1-2 decades later than the mean age for OS of long bones. The present case is a 62-year-old man with facial asymmetry and pain in his left upper jaw. Intraoral examination showed a bony hard, tender swelling about 50 x 60 mm in diameter in the maxillary alveolar ridge extending unilaterally from the maxillary incisor to the molar region which had expanded the buccal and palatal aspects of alveolar ridge. Computed tomography showed a hyper dense mass in the left maxilla extending to maxillary sinus. The diagnosis of OS was confirmed by histopathologic evaluation. Following the initial surgery, a local recurrence developed in the facial region of the patient within 18 months. Radiographic evaluation of OS of maxilla is important for diagnosis. Early diagnosis and radical surgery are the keys to increasing survival rate.

Introduction: Chondroblastic osteosarcoma is an aggressive bone tumor characterized by chondroid matrix production with variable cellularity. This retrospective study is aimed to assess the demographic distribution, clinical behavior and oncological outcome of chondroblastic osteosarcoma. Methods: 27 patients (14 males, 13 females) with chondroblastic osteosarcoma were included. The site of involvement included: proximal tibia (41%), distal femur (26%) and distal tibia (15%).The mean age of patients was 17 years (S.D: 6.9 years) (range 6–45 years). Results: Painful swelling was the main complaint in all cases. Two patients were classified as Enneking III (lung) stage and the remaining patients had Enneking IIB stage. Post-neoadjuvant chemotherapy limb sparing surgery was performed in 70% of cases while in 30% of cases limb amputation was done. On histopathological examination of specimens mean necrosis was 64% (20–95%). Disease free survival (DFS) at 2 years was 46.4% and at 4 years was 27.9%. Median disease free survival was 24 ± 10.30 months. Overall survival (OS) at 2 years was 53.3% and at 4 years was 16.6%. Median overall survival is 28 ± 5.93 months. Conclusions: Chondroblastic osteosarcoma is associated with poor prognosis, high recurrence rate and metastatic potential with dismal long-term survival. Chondroblastic osteosarcoma is an aggressive histological variant of conventional osteosarcoma with frequent location around the knee joint, affecting young population. Chemotherapy with Methotrexate, Adriamycin, Cisplatin (MAP) regimen is a well-tolerated regimen, resulting in limb salvage surgery in majority of the cases. [ABSTRACT FROM AUTHOR]

In patients presenting to the operating room with a saddle pulmonary embolism for noncardiac surgery, it is best to take a multidisciplinary approach and involve the cardiac and vascular surgeons. [ABSTRACT FROM AUTHOR]

Adolescent and young adult (AYA) oral maxillofacial tumors are rare and account for ∼12% of all AYA cancers. Due to the low incidence of these malignancies, diagnostic considerations, therapeutic approaches, and factors affecting prognosis have been difficult to characterize. Given the anatomic structures located within the head and neck, patients are at risk for treatment-related morbidity that may adversely impact their quality of life. We present a single-institution case series of AYA patients with oral maxillofacial tumors treated at the University of Illinois at Chicago. A multidisciplinary treatment approach, including collaboration with the Oral Maxillofacial Surgery, Dentistry, and the Ear, Nose, and Throat teams along with the utilization of Children's Oncology Group treatment protocols, can serve as a model to address the challenges in the management of these complex cases. [ABSTRACT FROM AUTHOR]

Chondrosarcomas of the spine are rare tumors and represent <10% of all chondrosarcomas. In the spine, they may arise from vertebral bodies or posterior elements. They may occur in patients ranging from 13 to 78 years of age. Here, we present a case of a 25-year-old female who presented with complaints of lower backache, stiffness in both lower limbs, and tingling sensation in the right lower limb. On examination, both power and sensations were decreased below waist. Magnetic resonance imaging spine revealed an extradural lesion at D5 vertebral body level with severe cord compression. We received the mass in multiple fragments which were grayish-white and firm to hard in consistency. Microscopically, a chondroid tumor was seen with cells arranged in lobules in abundant myxoid matrix. The neoplastic chondrocytes were large in size and had bizarre hyperchromatic nuclei. Few binucleate and multinucleate forms were also seen along with occasional atypical mitoses. There was permeation and destruction of the host bone, and the tumor was seen invading the marrow spaces. Few foci showed high cellularity. No osteoid formation was seen by the tumor. The tumor was diagnosed as Chondrosarcoma – Grade II. [ABSTRACT FROM AUTHOR]

Osteosarcoma is the most common primary malignant bone tumor, with a higher prevalence among children and young adults. Its most frequent localization is in the distal femur, followed by the proximal humerus and the proximal femur. In this article we will describe the case of a 25-year-old male patient who presented to our medical facility, accusing spontaneous pain and swelling, both originating from the left knee. The X-ray of the distal femur showed a heterogeneous mass around the left femoral metaphysis with massive periosteal reaction. The computerized tomography (CT) analysis revealed cortical destruction, with extra-compartmental localization. The patient has later undergone to an incisional biopsy. The histopathology report showed the presence of a chondroblastic osteosarcoma. According to the multidisciplinary diagnosis, the tumor was finally classified as type IIB on the Enneking classification. In such cases, the elective surgical procedure is reconstructive surgery, consisting of wide resection of the distal femur, followed by modular reconstruction. After the surgery, the patient's condition improved significantly and the functional outcome of the reconstructed joint was also satisfying. [ABSTRACT FROM AUTHOR]

Osteosarcoma (OS) is a malignant tumor that induces formation of osteoid or immature bone and rarely occurs in maxilla. Maxillofacial OSs are reported to occur in the third to fifth decades that is 1-2 decades later than the mean age for OS of long bones. The present case is a 62- year-old man with facial asymmetry and pain in his left upper jaw. Intraoral examination showed a bony hard, tender swelling about 50 x 60 mm in diameter in the maxillary alveolar ridge extending unilaterally from the maxillary incisor to the molar region which had expanded the buccal and palatal aspects of alveolar ridge. Computed tomography showed a hyper dense mass in the left maxilla extending to maxillary sinus. The diagnosis of OS was confirmed by histopathologic evaluation. Following the initial surgery, a local recurrence developed in the facial region of the patient within 18 months. Radiographic evaluation of OS of maxilla is important for diagnosis. Early diagnosis and radical surgery are the keys to increasing survival rate. [ABSTRACT FROM AUTHOR]

Osteosarcoma of the jaw is a very rare and highly malignant tumor, which could be a manifestation of Li-Fraumeni syndrome - an inherited cancer syndrome characterized by a high frequency and wide spectrum of early onset neoplasms. Incidence of jaw osteosarcoma is only about 0.07/ 100,000 per year. The tumor'sstage and possibility of complete surgical removal have the biggest impact on patient prognosis. Because rare, osteosarcomas are often misdia gnosedinitially, which delays treatment and worsens the prognosis. We present a 32-year-old female patient with Li- Fraumeni syndrome andinitially misdia gnosed chondroblastic osteosarcoma. After incomplete resection and early local recur rence, which completely filled the defect after subtotal maxillectomy, we achieved curative response and more than 7 years disease-free survival with chemo-radiotherapy. Furthermore, we describe symp toms, dia gnosis, and treatment of this rare disease, and also focus on Li- Fraumeni syndrome. Outcome of this case report disagrees with the widely held tenet that chemo-radiother apy of osteosarcoma of the jaw is considered only a palliative treatment, unexpected response of some tumors to treatment, and the role of p53 mutationsstill are not clear and are the object of extensive investigations. [ABSTRACT FROM AUTHOR]

Primary osteosarcomas of the skull and skull base are rare and comprise

A 10-year-old spayed female Maltese dog presented to a local animal hospital with a subcutaneous mass (4×3×3 cm) in the right shoulder region. The mass was well circumscribed, with soft tissue opacity and variable levels of mineralization, but with no bony involvement in radiography. The mass was surgically removed. Upon histological examination, the mass consisted of malignant mesenchymal cells that had produced a chondroid matrix and osteoid. Round to polygonal neoplastic cells with large nuclei showed moderate anisokaryosis and variable numbers of mitotic figures. The tumor cells were positive for vimentin and osteocalcin and negative for pancytokeratin, S100, and C-kit. On the basis of histopathologic and immunohistochemical features, the tumor was diagnosed as an extraskeletal chondroblastic osteosarcoma. [ABSTRACT FROM AUTHOR]

Osteosarcoma is the most common primary malignant bone tumor, with a higher prevalence among children and young adults. Its most frequent localization is the distal femur, followed by the proximal humerus and the proximal femur. We will describe the case of a 25-year-old male patient who presented in our clinic, accusing spontaneous pain and swelling, both originating from the left knee. The X-ray of the distal femur showed a heterogeneous mass around the left femoral metaphysis with massive periosteal reaction. The computerized tomography (CT) revealed cortical destruction, with extra-compartmental localization. The patient has later undergone to an incisional biopsy. The histopathology report showed the presence of a chondroblastic osteosarcoma. According to the multidisciplinary diagnosis, the tumor was finally classified as type IIB on the Enneking classification. In such cases, the elective surgical procedure is reconstructive surgery, consisting of wide resection of the distal femur, followed by modular reconstruction. After the surgery, the patient's condition improved significantly and the functional outcome of the reconstructed joint was also satisfying. [ABSTRACT FROM AUTHOR]

Osteosarcoma (OS) is a rare tumor arising from immature bone forming cells or through neoplastic differentiation of other immature mesenchymal cells into osteoblasts. Chondroblastoma-like OS is one of the rare forms of OS to be seen in jaw bones. Aggressive clinical behavior, osteolytic areas in the radiograph and histological presentation of chondroblastoma such as cells with grooved nuclei, typical chicken-wire calcification along with areas of tumor osteoid, implied the diagnosis as chondroblastoma-like OS. Use of reticulin stain further confirmed the diagnosis. A case of chondroblastoma-like OS is reported, emphasizing the importance of early diagnosis of aggressive jaw lesions with the help of routine radiography, histopathology, and special stains.

Introduction: Malignant tumours located in maxillofacial region represent approximately 2-3% of all cancers and thus belonging to 10 most frequent malignancies. Approximately 85 to 95% of oral cancer is squamous cell carcinoma, which is well known type of cancer. Background: In these articles we report two uncommon tumors of maxillofacial region, which we encountered on department of Oral and Maxillofacial Surgery University Hospital Brno. The first rare tumour is chondroblastic osteosarcoma with incidence 0,07 cases per 100 000 population per year, the second is glomangiopericytoma, which represents 3% of all tumors of head and neck. Chondroblastic osteosarcoma is highly malignant tumor, while glomangiopericytoma belongs to category of borderline and low-malignant-potential soft-tissue tumors.

ABSTRACT Osteosarcoma has a well-recognized bimodal distribution, with the first peak in adolescence and another in the elderly age-group. The elderly patients have different clinical features and a poorer prognosis as compared to adolescents. To better understand the biological features of osteosarcoma in the elderly population, we established a new human osteosarcoma cell line from a 58-year-old man with primary chondroblastic osteosarcoma. After 6 months of continuous culture in vitro for over 50 passages, an immortalized cell line CHOS was established. The cell line was well-characterized by cytogenetic, biomarker, functional, and histological analyses. The CHOS cells exhibited a spindle-shaped morphology and a doubling time of 36 h. Cytogenetic analysis of CHOS cells revealed the loss of chromosome Y and the gain of chromosome 12. Quantitative real-time polymerase chain reaction (RT-PCR), Western blotting and/or immunofluorescence revealed the expression of chondroblastic, mesenchymal and tumor metastasis markers in the CHOS cells. Compared with the osteosarcoma cell line, the CHOS cells were found to be more sensitive to cisplatin and doxorubicin, but were resistant to methotrexate. The cell line was highly tumorigenic and maintained the histological characteristics and invasive nature of the original tumor. Furthermore, on immunohistochemical analysis, the xenografts and metastases were found to co-express collagen II, aggrecan, vimentin and S100A4 that resembled the original tumor cells. Our results indicate, the potential of CHOS cell line to serve as a useful tool for further studies on the molecular biology of osteosarcoma, especially in the elderly patients. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2116-2125, 2016. [ABSTRACT FROM AUTHOR]

BACKGROUND Chondroblastic osteosarcoma (COS) is a uniformly fatal bone malignancy if not diagnosed and treated appropriately in a timely manner. Fine-needle aspiration (FNA) of osseous lesions is routinely performed in major medical centers. Appropriate characterization of the tumor will significantly influence patient management and outcomes. METHODS A retrospective review of the cytopathology archives of 2 large tertiary care centers for a 15-year period (2001-2015) revealed 17 cases of COS (9 primary, 6 recurrent, and 2 metastatic cases) in 16 patients. Clinical outcome and histopathologic follow-up were reviewed and correlated. RESULTS There were 9 male and 7 female patients (male-to-female ratio of approximately 1:1), ranging in age from 12 to 70 years (mean age, 29.2 years). The classic locations for osteosarcoma were commonly involved, such as the long bones around the region of the knee in 4 cases and the proximal humerus in 1 case. However, other 'nonclassic' sites also were noted to be commonly involved, including the distal tibia or fibula (4 cases), sacroiliac region (4 cases), mandible (3 cases), and skull (1 case). Cytomorphologic characteristics were high cellularity; predominantly discohesive, single cells; small tissue fragments; background osteoid and chondroid matrix; spindled cells and plasmacytoid cells with moderate to abundant basophilic vacuolated cytoplasm and occasional multiple cytoplasmic processes; round to oval nuclei with anisonucleosis; and small to prominent nucleoli. There were scattered binucleated and multinucleated osteoclast-like giant cells. Cases with high-grade morphology demonstrated marked pleomorphism and abundant mitoses. CONCLUSIONS The differential diagnosis of COS includes chondroblastoma, chondrosarcoma, and chondroid chordoma. A definitive diagnosis can be made with clinical and radiological correlation. Cancer Cytopathol 2016;124:493-500. © 2016 American Cancer Society. [ABSTRACT FROM AUTHOR]

A 6-year-old Rhodesian Ridgeback was presented with a 1.5 year history of right forelimb lameness. Clinical, radiological and computed tomographic findings suggested the presence of fragmented medial coronoid process. A subtotal coronoidectomy was performed and, due to the atypical appearance of the medial coronoid process on imaging and at surgery, histopathology of the fragments was performed which revealed chondroblastic OS. Ten months after surgery, the dog was re-presented with the same clinical signs and the radiographic changes were suggestive of a recurrence of the OS. Palliative therapy was instigated at the owner's request. Thirty months after surgery of the neoplasm, the dog was presented with dyspnea. Thoracic radiographs showed lesions consistent with lung metastases. Euthanasia was requested by the owner, who declined post-mortem examination. [ABSTRACT FROM AUTHOR]

Osteosarcoma is the most common primary malignant mesenchymal tumor, accounting for approximately 20% of sarcomas, with 5% incidence in the jaws. They present various clinical and histological aspects as well as variable disease prognosis and outcome. About 50% of all osteosarcomas are osteoblastic, 25% fibroblastic, 25% chondroblastic. Metastasis of osteosarcoma in the oral cavity is rare, and very few cases have been described so far in the literature. This article presents a metastatic case of chondroblastic osteosarcoma in the mandibular right-attached gingiva arising from 4 th rib. This case report further suggests that chondroblastic osteosarcoma has poor prognosis.