Telangiectatic osteosarcoma(TAEOS) is a rare subtype of osteosarcoma(OS) composed of blood-filled or empty cystic architecture simulating aneurysmal bone cyst. TAEOSs account for 2-12% of all OSs. TAEOSs mostly develop around knee and proximal humerus, but TAEOSs of the jaws are rare. To the best of my knowledge, this is the fourth case of primary TAEOS affecting the jaws. A 36-year-old female who had been previously diagnosed osteosarcoma by biopsy reported with a chief complaint of throbbing and swelling of the right mandible. The patient received neoadjuvant chemotherapy followed by hemi-mandibulectomy. After surgery, patient received adjuvant chemotherapy. The patient is free of disease for 6 months after surgery. TAEOSs are mimicking other benign entities, such as aneurysmal bone cyst and central giant cell granuloma. Thus, careful diagnosis through thorough radiographic and histopathologic evaluation is important to establish a treatment plan, prognosis, prediction and management strategy.

It is well documented that giant cells can be observed in some types of odontogenic tumors such as central odontogenic tumor and dentinogenic ghost cell tumor. However, the presence of stromal giant cells has only rarely been reported in ameloblastoma, although being the most common epithelial odontogenic tumor. In this study, we present a novel case of peripheral ameloblastoma associated with peripheral giant cell granuloma arising in the mandibular alveolar mucosa of a 65-year-old male patient. The possible pathogenesis of this combined lesion will be discussed, in addition to the review of previous reports of ameloblastoma accompanied by stromal giant cells.

Sarcomatous transformation of fibrous dysplasia (FD) is rare and can occur in patients with McCune-Albright syndrome (MAS). To date, there have been several cases of malignant transformation of FD in the craniofacial area of patients with MAS. Here, we report an additional case of secondary osteosarcoma arising from FD in the mandible of a 41-year-old woman with MAS. The patient complained of rapid swelling in the right facial area, which was initially misdiagnosed as soft tissue sarcoma at another hospital. After neoadjuvant concurrent chemoradiotherapy resulting in poor response, the lesion was surgically resected in our hospital, and the final diagnosis of secondary osteosarcoma was rendered. Currently, post-operative adjuvant chemotherapy is in progress. As a result of our review of 17 reported cases showing malignant transformation in FD/MAS, the M/F ratio was 1:1.1, and the median age at onset of malignancy was 28.6 years. The most commonly affected site was the craniofacial bones (n=13; 76%), and the most common histopathologic type of malignancy was osteosarcoma (n=14; 82%). More than half of the patients (8/15; 53.3%) died within 1 year, mainly due to lung metastasis (6/8; 75%). Taken together, since MAS patients with malignant transformation of FD have a relatively poor prognosis, accurate diagnosis based on histopathologic findings as well as clinical and radiographic information is important to select optimal treatment.

Perineural invasion (PNI) is the underestimated metastatic pathway and has been widely recognized as a negative prognostic factor in many human cancers. L1CAM is one of members of the immunoglobulin-like cell adhesion molecule (CAM) family, which play a role in neural development. Moreover, a new role of L1CAM outside the nervous system has been revealed. Overexpression of L1CAM was involved in the tumor progression and LN metastasis in various malignancies. In the present study, presence of PNI and L1CAM expression were examined to define their prognostic values in OSCC. In addition, association of L1CAM expression with presence of PNI was assessed to define the value as a candidate molecule supporting the diagnosis of PNI. We found that presence of PNI significantly correlated with LN metastasis and advanced clinical stage. L1CAM expression also significantly correlated with differentiation, lymph node metastasis, advanced clinical stage, as well as presence of PNI. Our results suggest that L1CAM seems to play a role in tumor progression, possibly through the PNI-related mechanism and could be a molecular marker for supporting the presence of PNI and predicting clinical outcome in OSCC.

The aim of this study was to present the clinical, radiological, and histopathological findings of 20 new Korean GOC cases with a brief literature review. The mean age of 20 GOC patients was 43.5 years (range, 29-73 years) with a strong predilection for male (male-to-female ratio, 4:1). Nine cases were located in the maxilla and 11 cases in the mandible. Eight cases involved the anterior areas of the jaws and 12 cases were located in the posterior area. Most of the cases (16/20, 80.0%) showed a well-defined unilocular radiolucency and some showed cortical perforation (55.6%) and bony expansion (72.2%) in computed tomography. The most common histopathological feature was eosinophilic cuboidal cells (100%), followed by clear cells (95.0%), mucous cells (85.0%), variations in thickness (85.0%), and intraepithelial microcysts (80.0%). All cases were surgically treated by enucleation and no recurrences were found in routine follow-up.