Outcome of Primary Intraosseous Carcinoma: Cases Review of Single Institution

Objective: The purpose of this study was to investigate the prognostic factors and treatment of primary intraosseous carcinoma (PIOC).Methods: Patients who diagnosed with PIOC and received treatment in Sichuan cancer hospital from 1996 to 2020 were followed up and retrospectively reviewed. Univariate and multivariate analyses base on clinical-pathological characteristics and therapeutic modalities were performed using the Log rank test and Cox regression model respectively.Result: A total of 28 patients were included in the study, with a mean age of 60 years (60±10.11). The 2-year and 5-year overall survival (OS) were 60.7% and 38.5% respectively. In the univariate analysis, surgery combined with adjuvant therapy improved the OS compared with surgery or radiotherapy alone (P=0.035), and patients received postoperative adjuvant radiotherapy had a higher OS than those who received radical radiotherapy (P = 0.01). In addition, patients with well differentiated tumors tent to have increased progression free survival (PFS) (P=0.01). Multivariate analyses showed that radiotherapy was independent indicators for OS (HR: 0.212, 95% CI: 0.068–0.660, P = 0.007).Conclusion: surgery combined with adjuvant therapy is the superior treatment strategy for primary intraosseous carcinoma at present. This study is the first to report the important role of radiotherapy in the treatment of primary intraosseous carcinoma.Mini Abstract：surgery plus adjuvant therapy is the preferred treatment for primary intraosseous carcinoma and it is first to illustrate the important role of radiotherapy.

53 A Rare Malignant Lesion of the Jaws

Introduction Primary intraosseous carcinoma (PIOC) of the jaw is an incredibly rare lesion with approximately 200 cases reported in the literature. PIOC are mostly asymptomatic incidental radiographic findings and present as poorly-defined, non-corticated radiolucencies often with root resorption and cortical perforation. Prognosis is considered poor and best predicted by histological grade. Case report A gentleman in his 50s presented to his dentist with a draining sinus from his LR6 tooth. A radiograph revealed a non-corticated radiolucency localised to the distal root of the LR6. 7 months later, he returned with pain and mobility of the LR7. Another radiograph revealed a non-corticated radiolucency from around the distal root of the LR6 extending to the LR8. Urgent biopsy of the mandibular bone was arranged by the oral and maxillofacial surgery team. Histopathology revealed the lesion was likely a benign squamous odontogenic tumour. However, it was not possible to exclude a well-differentiated squamous cell carcinoma. Correlation of clinical findings, imaging and multidisciplinary team discussion was recommended. Following the MDT meeting, excision of the bony lesion was undertaken. Histopathology this time returned as primary intraosseous carcinoma NOS T4N0M0, thought to have arisen from a radicular cyst associated with the LR6/7. The treatment was right segmental mandibulectomy, fibular free flap, selective neck dissection (I-III) and adjuvant radiotherapy. Conclusions This case highlights how subtle radiographic features can represent malignancy in lesions appearing cystic at first. Although rare, clinicians should be aware of PIOC as a differential diagnosis when presented with radiographic features which could represent malignancy.

Primary Intraosseous Carcinoma Arising from Odontogenic Keratocyst - A Case Report

Primary intraosseous carcinoma (PIOC) previously named as primary intraosseous squamous cell carcinoma (PIOSCC), derived from an odontogenic keratocyst (OKC) is a locally aggressive rare malignant neoplasm of the jaws with poor prognosis. The incidence of carcinomas arising from odontogenic cysts was reported to be approximately 1 – 2 / 1000. The knowledge of the histopathological features of PIOC allows accurate and early diagnosis of the lesion so that an early and appropriate treatment can be instituted for better prognosis. Primary intraosseous squamous cell carcinoma (PIOSCC) is a carcinoma arising from the central bone without any initial connection to various epithelia.1 In 2017, according to WHO classification of tumours, it was renamed as primary intraosseous carcinoma (PIOC).2 According to the current WHO classification, PIOC is a central jaw carcinoma that cannot be classified as any other condition and presumably has developed from odontogenic cysts or other benign precursors. The most common odontogenic cysts having a significant probability of malignant transformation are dentigerous cysts, residual periapical cysts, and odontogenic keratocysts (OKCs).3,4 The transition from this benign cystic lining to squamous cell carcinoma may remain clinically undetected, and the delay in diagnosis has a significant influence on treatment and prognosis.5 Therefore, the initial radiographic features of PIOC arising from an OKC (PIOC ex - OKC) are similar to those of benign odontogenic tumours or cysts, including conventional OKCs.4 Hence, it is mandatory to further investigate it histopathologically for final diagnosis and proper treatment plan. Malignant changes in OKCs have been rarely reported. To the best of our knowledge, very few cases of PIOC ex - OKC have been described in the literature. The purpose of this article is to report a case of PIOC that originated from an OKC and to shed light on the process of malignant transformation of this rare lesion. Here, is the case report describing an extremely rare case of PIOC of the maxilla derived from an OKC in a 45 - year - old female patient.

Primary Intraosseous Carcinoma in the Pediatric Mandible

Background: Primary intraosseous carcinoma (PIOC) is a rare malignant odontogenic tumor that predominantly occurs in males older than 50 years. PIOC can be misdiagnosed as odontogenic cyst because it occasionally shows well-defined border on radiography. In this study, a case of a 14-year-old female with PIOC who was misdiagnosed with odontogenic cyst clinically is reported along with a literature review of pediatric PIOC cases.Case Presentation: A 14-year-old female patient presented with painful swelling on the mandibular right premolar area. There was a radiolucent lesion with a well-defined border in panoramic view. She was diagnosed with odontogenic cyst, and the cystic mass was enucleated with extraction. However, the biopsy result was consistent with PIOC. After cancer work-up, she underwent partial mandibulectomy, selective neck dissection, and reconstruction with a fibular free flap. Although the surgical resection margins were clear, local recurrence and lung metastasis occurred four months after surgery. She underwent concurrent chemo-radiation therapy, but the prognosis was poor.Conclusions: PIOC should be diagnosed differentially from odontogenic cyst even in pediatric populations.

An extensive sclerosing odontogenic carcinoma in mandible: a case report and literature review

Sclerosing odontogenic carcinoma (SOC) is a primary intraosseous carcinoma of the jaw that was listed as a separate entity for the first time in the latest version of the World Health Organization classification of Head and Neck Tumors (2017). In this report, we present a case of SOC involving a circuitous diagnostic process because of the inadequately detailed biopsy findings and inherent impression based on the imaging manifestations. Through an extensive literature review, the histopathological and immunohistochemical features of the disease were briefly summarized. Radiological findings of SOC have been characterized in detail, and an imaging classification scheme has been proposed to further discuss the diversity of radiographic features. Due to the rarity of the disease, a comprehensive understanding of SOC is needed, and close collaboration between clinicians, radiologists, and pathologists is crucial to avoid misdiagnosis.