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Objective: To establish an animal model of oral squamous cell carcinoma invading the mandible through multi-sample experiments that verified the stability, repeatability, tumorigenicity and mandible destruction rate of the model., Methods: Oral squamous cell carcinoma cell suspension was injected into the outer side of the mandible through the anterior edge of the masseter muscle of naked mice to observe the tumourforming process. Then, the anatomical, histological and imaging examinations were carried out to determine whether the tumour had invaded the mandible. By comparing the tumour growth of multiple groups of various squamous cell carcinoma cells (CAL27, HN6 and HN30 cells), the changes in body weight and characteristics of tumour formation were compared, and the experience was summarised to further verify the stability, repeatability, tumour formation rate and arch damage rate of the model., Results: The subsequent specimens of tumour-bearing nude mice were validated once the model had been established. In vitro, tumour tissue wrapped around the mandible's tumour-bearing side, and the local texture was tough with no resistance to acupuncture. Haematoxylin and eosin staining revealed that squamous cells were infiltrating the mandible in both the horizontal and sagittal planes. Microcomputed tomography results showed that the mandible on the tumour-bearing side displayed obvious erosion damage. Cell lines with various passage rates clearly had diverse tumour-bearing life cycles., Conclusion: This study successfully established an animal model of oral squamous cell carcinoma invasion of the mandible. The model has excellent biological stability, repeatability, tumorigenesis rate and mandible destruction rate.

Extensive bimaxillary bone support devices(hereafter referred to as a dental implant)are useful for morphological and functional reconstruction after resection of oral cancer. However, tumor recurrence due to peri-implantitis may occur. In this report, we describe a case of squamous cell carcinoma(SqCC)recurrence around a mandibular dental implant. An 80-year- old female patient underwent tumor resection and stratification for SqCC extending from the left lingual margin to the gingiva of the left lower molar in 2013. In 2014, 2 dental implants were placed in the bilateral mandibular canine region and a prosthetic device of implant-overdenture was installed. Six years after the primary tumor resection, a mass lesion was found in the peri-implant area of the left mandibular canine. Upon examination, the patient was diagnosed with SqCC recurrence and underwent radical tumor resection and immediate reconstruction using a submental flap and a reconstruction plate. Additional dental implants were concurrently placed in the remaining mandible. There was no evidence of recurrence, and the patient remains under careful observation so far.

Resection margins are frequently studied in patients with oral squamous cell carcinoma and are accepted as a constant prognostic factor. While most evidence is based on soft tissue margins, reported data for bone resection margins are scarce. The aim of this retrospective study was to evaluate and determine the utility of surgical margins in bone resections for oral cavity squamous cell carcinoma (OCSCC). The status of bone resection margins and their impact on survival was investigated in patients who had undergone segmental mandibulectomy for OCSCC. Medical records were retrieved for the years 2000-2012; 127 patients were identified and included in the study. Tumour-positive bone resection margins were found in 21% of the patients. The 5-year overall survival was significantly lower in this group (P<0.005). Therefore, there is a need for intraoperative feedback on the status of bone resection margins to enable immediate additional resection where necessary. Although the lack of intraoperative methods for the evaluation of bone tissue has been addressed by many authors, there is still no reliable method for widespread use. Future research should focus on an objective, accurate, and rapid method of intraoperative assessment for the entire bone resection margin to optimize patient outcomes., (Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Purpose: To study an original 3D visualization of head and neck squamous cell carcinoma extending to the mandible by using [18F]-NaF PET/CT and [18F]-FDG PET/CT imaging along with a new innovative FDG and NaF image analysis using dedicated software. The main interest of the 3D evaluation is to have a better visualization of bone extension in such cancers and that could also avoid unsatisfying surgical treatment later on., Patients and Methods: A prospective study was carried out from November 2016 to September 2017. Twenty patients with head and neck squamous cell carcinoma extending to the mandible (stage 4 in the UICC classification) underwent [18F]-NaF and [18F]-FDG PET/CT. We compared the delineation of 3D quantification obtained with [18F]-NaF and [18F]-FDG PET/CT. In order to carry out this comparison, a method of visualisation and quantification of PET images was developed. This new approach was based on a process of quantification of radioactive activity within the mandibular bone that objectively defined the significant limits of this activity on PET images and on a 3D visualization. Furthermore, the spatial limits obtained by analysis of the PET/CT 3D images were compared to those obtained by histopathological examination of mandibular resection which confirmed intraosseous extension to the mandible., Results: The [18F]-NaF PET/CT imaging confirmed the mandibular extension in 85% of cases and was not shown in [18F]-FDG PET/CT imaging. The [18F]-NaF PET/CT was significantly more accurate than [18F]-FDG PET/CT in 3D assessment of intraosseous extension of head and neck squamous cell carcinoma. This new 3D information shows the importance in the imaging approach of cancers. All cases of mandibular extension suspected on [18F]-NaF PET/CT imaging were confirmed based on histopathological results as a reference., Conclusions: The [18F]-NaF PET/CT 3D visualization should be included in the pre-treatment workups of head and neck cancers. With the use of a dedicated software which enables objective delineation of radioactive activity within the bone, it gives a very encouraging results. The [18F]-FDG PET/CT appears insufficient to confirm mandibular extension. This new 3D simulation management is expected to avoid under treatment of patients with intraosseous mandibular extension of head and neck cancers. However, there is also a need for a further study that will compare the interest of PET/CT and PET/MRI in this indication., (Copyright © 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Objective: Carcinoma cuniculatum (CC) is a rare variant of squamous cell carcinoma. We describe the clinicopathologic findings in a new case., Study Design: This is a literature review and retrospective study of a case with CC., Results: The clinical and imaging findings of CC are diverse; some cases might be challenging to diagnose accurately by biopsy. This article reports a case of CC that occurred in the retromolar region with involvement of the mandible. The patient was a 39-year-old man. Clinically, the lesion manifested as an ulcerative mass in the mandibular molar region. Imaging results showed that the lesion in the jaw exhibited moth-eaten destruction without obvious expansion of the jaw bone. The postoperative pathologic examinations were consistent with CC; additionally, metastases were present in 1 level II lymph node and 1 submandibular lymph node. Left soft tissue metastasis and right cervical lymph node metastases were detected 10 and 27 months after surgery, respectively., Conclusions: CC is a rare epithelial malignant tumor and has variable clinical manifestations. The diagnosis of CC mainly depends on pathologic features. Most patients with CC have a good prognosis; only a small percentage of patients might experience lymph node metastasis., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Squamous cell carcinoma (SCC) is the most common nonodontogenic oral tumor in cats. In the jaw, it usually presents as an ulceroproliferative lesion associated with enlargement of the affected bone., Case Presentation: This report describes the case of a cat in which clinical and radiographic findings of a mandibular swelling were suggestive of an aggressive process, but the oral mucosa was unaffected. The results of histopathological and immunohistochemical examination of the samples obtained from the intraosseous lesion were consistent with SCC. The animal was euthanized 5 months after initial presentation as a result of the severe progression of the disease, and no other primary tumors were identified at necropsy., Conclusions: Based on the clinicopathological, microscopic, and immunohistochemical staining features, as well as the absence of a primary tumor at a distant site, we propose that the term, solid type primary intraosseous SCC (PIOSCC), be used to describe this neoplasia, as it shares similar features with human PIOSCC.

Background: The term "primary intraosseous squamous cell carcinoma" was introduced in 2005 by the World Health Organization with three subcategories. Squamous cell carcinoma arising from the lining of an odontogenic cyst is one important rare subcategory of such lesions with an incidence of 0.01 to 0.02%. Furthermore, the appearance of such malignancy in an odontogenic tumor such as keratocystic odontogenic tumor is considered extremely rare., Case Presentation: In this case report we report a case of a 50-year-old Sri Lankan woman who complained of pain and increase in the size of a swelling at the anterior mandible, which had been present for over 1 year. The increase was significant for 1 month with accompanying numbness of the left half of her lip. Cone beam computed tomography results revealed an irregular radiolucent lesion involving most of her mandible and, except in the anterior part, very little buccolingual expansion was seen that suggested a keratocystic odontogenic tumor. An excision biopsy of the cyst lining confirmed a squamous cell carcinoma arising from a preexisting keratocystic odontogenic tumor., Conclusions: Even though primary intraosseous squamous cell carcinoma arising from a keratocystic odontogenic tumor is considered to be very rare, the present case is comparable to most of the aspects cited in the literature. The current case emphasizes the importance of careful investigation of swellings present in the mandible. Clinicians as well as patients should be aware and detect these changes to avoid being clinically negligent.

Background: Radiologic assessment of mandibular bone invasion is critical in evaluating the extent of bone resection required in patients with oral cancer. There are a few reports of improved sensitivity with cone-beam CT (CBCT) over conventional CT., Methods: A prospective cohort study of patients with oral squamous cell carcinomas adjacent to the mandible requiring marginal or segmental mandibular resection was performed. Patients were treated based on clinical assessment and conventional cross-sectional imaging. Patients and surgeons were blinded to the results of CBCT performed preoperatively. Pathologic examination served as the gold standard., Results: Forty-five patients were included in the study. Thirty-three percent of the patients underwent segmental mandibulectomy and 37% had bone invasion. The sensitivity and specificity of CBCT were 91% and 60%, respectively, compared to 86% and 68% for CT with bone windows., Conclusion: A CBCT offers marginally improved sensitivity at the cost of reduced specificity for assessment of bone invasion compared to CT., (© 2017 Wiley Periodicals, Inc.)

Squamous cell carcinoma is the most common cancer within the oral cavity. Bone invasion involving the maxilla or mandible is reported in up to 50% of tumors on initial presentation. Although conflicting data exist, true bone invasion is thought to negatively affect risk of recurrence and long-term prognosis. The ultimate goal is to accurately identify bone invasion preoperatively and intraoperatively, because it affects the treatment plan. This article focuses on methods of evaluation of the bone margin in the preoperative and intraoperative setting, discussing the implications for prognostic, staging, and reconstructive methods., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Primary intraosseous squamous cell carcinoma (PIOSCC) is a rare malignant neoplasm that has an exquisitely exclusive affection to the jawbone. It is defined as squamous cell carcinoma arising within the jaw and developing from residual odontogenic epithelium or from a preexisting odontogenic cyst or tumor. The solid-type of this tumor is a central jaw carcinoma arising de novo and has no initial connection with the oral mucosa. Herein, we report a case of solid-type PIOSCC involving the mandible in a 37-year-old male patient elucidating its histopathological and imaging findings. The patient underwent surgical resection followed by post-operative adjuvant radiotherapy. The close 2-year follow up of the patient revealed neither locoregional nor distant metastasis., (Copyright © 2016 King Faisal Specialist Hospital & Research Centre. Published by Elsevier Ltd. All rights reserved.)

Oral squamous cell carcinoma (OSCC) around a dental implant is a rare pathologic condition. This report describes a case of recurrent OSCC surrounding a dental implant, histopathologic findings, and a literature review of this condition. A 58-year-old Japanese woman underwent chemoradiotherapy for OSCC in the right lower gingiva, resulting in a complete response. Nine years after primary chemoradiotherapy, a dental implant was placed in her atrophic mandible. Three years later, an OSCC developed around the dental implant in the right lower premolar region. Marginal mandibulectomy was performed. Microscopic examination showed medullary invasion around the implant surface, suggesting that tumor infiltration of the bone was through the interface between the implant and bone. However, no downward invasion through the interface was evident. OSCC can develop around dental implants that are placed for oral rehabilitation after ablative surgery. Staging of OSCC and planning of surgical management should be carried out carefully, because implants placed adjacent to the OSCC can influence tumor invasion. A high degree of vigilance for OSCC is required during follow-up of patients with dental implants who have OSCC risk factors such as premalignant lesions. Detailed evaluation, including biopsy examination, is essential for distinguishing peri-implantitis from OSCC., (Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

A rare case of primary intraosseous squamous cell carcinoma arising in an odontogenic keratocyst (OKC) is presented here, with the clinical and histologic features of the first biopsy showing characteristics of OKC and the second biopsy disclosing a squamous cell carcinoma. Immunoprofile of this case was compared with five cases of classical OKC by using cytokeratins CK5, CK14, and CK19, CD138, p63, Ki-67, p53, and bcl-2. Classic OKCs showed expected positivity, mainly in the basal and/or suprabasal layers with most antibodies, except for p53, which was negative, whereas the present case showed irregular positivity in all layers, indicating that this can be useful for differential diagnosis and suggesting a possible role in malignant transformation into primary intraosseous squamous cell carcinoma. In conclusion, immunohistochemical differences between the first biopsy of the present case and classic OKC suggest that immunohistochemistry can be helpful in cases with areas of subtle initial malignant transformation., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Carcinoma cuniculatum is a rare form of well-differentiated squamous cell carcinoma that is often misdiagnosed. It has a propensity for local invasion and rarely metastasizes. Oral carcinoma cuniculatum is exceedingly rare, with very few reported cases in the English-language literature. Classically, its presentation mimics osteomyelitis or a dental abscess, resulting in misdiagnosis, multiple biopsy examinations, and procedures before a final diagnosis of carcinoma cuniculatum. This case report describes the case of a 71-year-old woman who was referred to the authors' clinic for evaluation of persistent pain and swelling of the mandible. Multiple biopsy examinations were negative for malignancy, and the patient was misdiagnosed with osteomyelitis and dental abscess before obtaining an accurate diagnosis of carcinoma cuniculatum. The aim of this report is to provide a thorough clinical and histopathologic report of carcinoma cuniculatum of the mandible, provide a brief review of the literature, and highlight the difficulties in arriving at this uncommon diagnosis., (Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

A patient with history of mandible squamous cell carcinoma underwent an FDG PET/CT scan. A focal hypermetabolic right ventricle lesion was noted and suggestive of metastasis. A cardiac MRI verified the right ventricle wall mass. Further endomyocardial biopsy confirmed the diagnosis of metastatic squamous cell carcinoma.

Neoplasms of retromolar trigone have important peculiarities due to their spatial relationships with the surrounding structures. Tumours that involve this area can extend to nearby muscles; adipose spaces; and other anatomic structures, such as the soft palate, the tonsillar fossa, the parapharyngeal space, and the floor of the mouth. In spite of a relatively quick diagnosis, the real extent of these tumours is typically underestimated at clinical examination. Our purpose was to propose a systematic approach to the use of multiplanar computed tomography reconstructions to evaluate normal retromolar trigone anatomy and the main pathways of spread for tumours that arise in this area. To our knowledge, only few reports exist in literature about this topic and none are about the usefulness of multidetector computed tomography and multiplanar reconstructions., (Copyright © 2014 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.)

Purpose: Squamous cell carcinoma is a common entity among adult head and neck cancer patients, with many requiring reconstruction post resection. Conversely, this entity is rare among children with major reconstruction even more unique. This case and the concomitant review of literature highlight the intricacies of pediatric facial reconstruction., Methods: The case described is of a 6-year-old African-American boy with poor dentition and a painful, 1.5 cm epiphytic lesion on the alveolar ridge of the left mandible. Incisional biopsy and computerized tomography were employed to obtain diagnosis and extent of disease. Surgical resection and reconstruction followed., Results: Incisional biopsy confirmed the diagnosis of squamous cell carcinoma. Maxillofacial computerized tomography confirmed the extent of the mandibular lesion. After interdisciplinary discussion and weighing options with the family, a segmental mandibulectomy, neck dissection, and right fibula free flap reconstruction with titanium 2.0 mm metal plate fixation was performed. Re-examination post-operatively showed complete coverage of the defect and the ability to restore excised dentition., Conclusion: Squamous cell carcinoma within the pediatric population occurs less often than sarcomas, but may necessitate major reconstruction. Without rigid reconstruction, contracture may result. The current consensus favors microvascular bone reconstruction. However, a lack of consensus exists regarding the timing of dental rehabilitation., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Aim: To reinvestigate the accuracy of 16 section multidetector computed tomography (MDCT) in assessing mandibular invasion in retromolar trigone (RMT) squamous cell cancers (SCC)., Materials and Methods: A search for diagnosed cases of early RMT SCC that were both imaged and treated at Tata Memorial Centre, Mumbai, India, between 2007 and 2010, was undertaken and yielded 37 patients. The average tumour size was 2.6 cm. All patients had undergone segmental, marginal, or hemimandibulectomy within 2 weeks of imaging. Imaging records archived on the picture archiving and communication system (PACS) were analysed. Contrast-enhanced CT had been performed using a 16 section MDCT system using the puffed-cheek technique. Image acquisition was at 2.5 mm section thickness, but axial images and isotropic coronal and sagittal multiplanar reformations were generated ad hoc from 0.625 mm retro-reconstructed images. Optimal oblique reformations were generated at will by the radiologist to depict the RMT in its entirety. The soft-tissue algorithm and bone window or bone algorithm reformations and axial images were analysed on a volume viewer integrated within the PACS using triangulation. Two investigators independently studied the images and these were compared with the findings at histopathology., Results: The sensitivity, specificity, and accuracy of 16 section MDCT for mandibular cortical and marrow invasion was 94, 90, and 91.8% and 83, 92, and 89%, respectively. Use of ad hoc generated oblique reformation contributed to the enhanced sensitivity and specificity. The accuracy for inferior alveolar canal invasion was 100%. There was excellent agreement between the two observers., Conclusion: Sixteen-section MDCT used to its full potential has high accuracy for the detection of mandibular invasion in RMT SCC., (Copyright © 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Primary intraosseous squamous cell carcinoma (PIOSCC) is a rarely reported neoplasm resulting from malignant transformation of a dentigerous cyst of the mandible or maxilla. Until 2010, only 116 cases had been described. The diagnosis of PIOSCC is difficult because of non-specific symptoms. A case of a 66-year-old patient with PIOSCC arising from a dentigerous cyst of the mandible is presented. Both pathologists and clinicians should be aware of the probability of malignant transformation of dentigerous cysts during the two-stage treatment. The patient should be subject to regular clinical and radiographic examination.

Primary intraosseous squamous cell carcinoma (PIOSCC) is a rare malignant odontogenic tumor arising from odontogenic epithelial remnants within the jawbones. PIOSCC is histopathologically divided into 3 types: solid-type carcinoma, carcinoma derived from a keratocystic odontogenic tumor, and carcinoma derived from an odontogenic cyst. In this article, we report a case of solid-type PIOSCC involving reactive bone formation in the mandible in a 60-year-old female patient together with its histopathological and imaging findings., (Copyright © 2012 Elsevier Inc. All rights reserved.)

In patients with oral squamous cell carcinomas (OSSC) it is desirable to avoid unnecessary bone resection without neglecting the overall surgical treatment goal of tumor-free margins. Whereas computed tomography (CT) is most commonly used to detect mandibular invasion, there are conflicting reports regarding the accuracy of CT. Therefore, the aim of this study was to reinvestigate the accuracy of CT in predicting mandibular involvement by OSSC. One hundred and seven patients with OSSC who received a mandibulectomy were included. Before treatment all patients underwent a contrast-enhanced multi-detector CT. Axial 3 or 1.25 mm thick images were reconstructed for evaluation in overlapping technique and displayed in a bone (1400/400 HU) and a soft tissue window (350/50 HU). CT scans were examined by three investigators and compared with the histological findings. The radiological examination showed a high interrater reliability (Cronbachs alpha 0.982). Comparing the radiological findings with the histological results the CT showed 8 false-positive results and 8 false-negative patients. The quality criteria for detecting bone involvement of OSSC by CT were calculated as follows: sensitivity 82.6%; specificity 86.9%; positive predictive value 82.6%; negative predictive value 86.9%. However, in all false-positive patients a sagittal bone defect of 15.1mm could be found presumably caused by pressure of the tumor, but no histologically detectable bone infiltration. Modern CT (1-2 mm sections) is a valuable tool for surgical treatment planning. If bone invasion is detected, a mandibulectomy seems always reasonable. In radiologically negative cases histological assessment is necessary to detect mandibular involvement., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: Cuniculatum carcinoma is a well-differentiated form of squamous cell carcinoma that shares histologic characteristics with papillary squamous cell carcinoma and verrucous carcinoma. Cuniculatum carcinoma usually occurs on the plantar region, and only 16 cases involving the oral cavity have been described in the literature., Methods: The authors have reported 3 cases of mandibular cuniculatum carcinoma. All of the patients were in a great deal of pain. Histologic diagnosis was difficult due to the presence of few cellular atypies. Clinical criteria, osseous lysis, and the coexistence of multiple intraosseous well-differentiated, hyperkeratotic papillomatous lesions with few cellular atypies sign the diagnosis., Results: No local recurrence has been reported after treatment with radical surgery alone., Conclusion: The diagnosis is often delayed. Although cuniculatum carcinoma displays aggressive behavior locally, lymph node infiltration and metastasis are rare. The therapy of choice is surgical removal with free margins, after which the prognosis is excellent., (Copyright © 2010 Wiley Periodicals, Inc.)

This preliminary retrospective study evaluates the diagnostic value of cone-beam computed tomography (CBCT), as a potential standard preoperative procedure, in assessing mandibular invasion by oral squamous cell carcinoma (OSCC) compared with conventional preoperative panoramic radiography (PR), magnetic resonance imaging (MRI) and histological examination of the resection specimen (the golden standard). Between September 2006 and September 2009, 23 patients with histology proven primary OSCC, adjacent to or fixed to the mandible were included. The tumours were classified into four groups, ranging from no bone invasion to evident bone invasion. Sensitivity and specificity for PR were 55% (95% CI [0.350;0.619]) and 92% (95% CI 0.737;0.984]), respectively, both were significantly lower than the 91% (95% CI [0.740;0.909]) and 100% (95% CI [0.845;1]), respectively, for CBCT. MRI showed 82% sensitivity (95% CI [0.608;0.941]) and 67% specificity (95% CI [0.474;0.779]). CBCT has the potential to become a new diagnostic tool in the OSCC screening procedure to predict mandibular invasion or erosion, but its value may be limited by its relatively low sensitivity. A prospective study will start on 64 patients (alpha=0.05; power 0.8; effect size 0.5) to improve these results statistically., (Copyright 2010 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Purpose: To evaluate the diagnostic accuracy of cone-beam CT in assessing mandibular invasion by lower gingival carcinoma and compare it with that of panoramic radiography., Patients and Methods: Fifty patients with squamous cell carcinoma of the lower gingiva who were examined by both panoramic radiography and cone-beam CT before surgery were included in this study. Five radiologists used a 6-point rating scale to independently evaluate cone-beam CT and panoramic images for the presence or absence of alveolar bone and mandibular canal involvement by tumor. Using the histopathogical findings as the gold standard, we calculated and compared the area under the receiver operating characteristic curve (Az value) and the sensitivity and specificity of the two imaging modalities., Results: In evaluations of both alveolar bone and mandibular canal involvement, the mean Az value for cone-beam CT (0.918 and 0.977, respectively) was significantly higher than that for panoramic radiography (0.793 and 0.872, respectively). The mean sensitivity for cone-beam CT (89% and 99%, respectively) was significantly higher than that for panoramic radiography (73% and 56%, respectively). There was no significant difference in the mean specificity. While cone-beam CT could provide high-resolution three-dimensional images, the image quality around the alveolar crest was often hampered by severe dental artifacts and image noise, resulting in difficulties in detecting subtle alveolar invasion., Conclusion: Cone-beam CT was significantly superior to panoramic radiography in evaluating mandibular invasion by lower gingival carcinoma. Its diagnostic value in detecting subtle alveolar invasion, however, may be limited by severe dental artifacts and image noise.

Squamous cell carcinoma (SCC) derived from keratocystic odontogenic tumor is an extremely rare tumor that is limited to the jaws. Most intraosseous carcinomas originate from the epithelial lining of odontogenic cysts, so they are called odontogenic carcinomas. They occur more frequently in men and the mean age of patients is 57 years. The following report describes an extremely rare case of an odontogenic carcinoma derived from a keratocystic odontogenic tumor in a 20-year-old man. The patient presented with an exophytic lesion in the retromolar region of the mandible which was first noticed by the patient 25 days earlier. In panoramic radiograph a well-defined radiolucency around the impacted 3rd molar was observed. Clinical and radiographic diagnosis was odontogenic SCC. Surgical resection was performed and histhopathologic examination of the lesion confirmed the diagnosis of SCC in the wall of a keratocystic odontogenic tumor.

Objectives: The prevalence of distant metastasis and second primary tumors is increasing with improved locoregional control in patients with head and neck squamous cell carcinoma. Traditionally, clinicopathologic evidence has been the gold standard used to distinguish distant metastasis from second primary tumors. We report a case in which loss of heterozygosity testing was used to clarify the clonal relationship between the 2 sites of head and neck squamous cell carcinoma., Methods: A patient with squamous cell carcinoma in the larynx and mandible underwent loss of heterozygosity testing., Results: The loss of heterozygosity testing confirmed that the mandibular cancer was a metastatic presentation of the laryngeal squamous cell carcinoma., Conclusions: We conclude that loss of heterozygosity testing can be useful in differentiating distant metastasis from second primary cancers in patients with 2 sites of head and neck squamous cell carcinoma, consequently providing important prognostic and staging information.

Background: Mandibular bone destruction is a frequent occurrence in oral squamous cell carcinoma. However, the relationship between the bone destruction and associated factors is unclear. Here, the role and diagnostic utility of connective tissue growth factor (CCN2) in bone destruction of the mandible was investigated., Patients and Methods: The production of CCN2 was explored by using immunohistochemistry on paraffin-embedded tissues from 20 cases of mandibular squamous cell carcinoma. The effect of CCN2 on osteoclastogenesis was examined in vitro by using total bone marrow cell populations from male mice., Results: Immunohistochemical analysis showed that CCN2-positive signals were closely associated with destructive invasion of the mandible by oral squamous cell carcinomas. Consistent with these results, recombinant human CCN2 (rCCN2) stimulated tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like cell formation in vitro., Conclusion: CCN2 can be considered a diagnostic marker and target for treatment in oral osteolytic mandibular squamous cell carcinoma.

Purpose: To investigate the role of 18-fluorine-fluorodeoxyglucose positron emission tomography/computerized tomography ((18)F-FDG PET/CT) in the preoperative prediction of the presence and extent of neck disease in patients with oral/head and neck cancer., Patients and Methods: Seventy patients were enrolled in the study, 47 of whom had a clinically negative neck (N0), 19 of whom had a clinically positive unilateral neck (N+), and 4 of whom were negative on 1 side of the neck and positive on the other. Each patient underwent a PET/CT study before undergoing selective neck dissection for N0 disease or modified radical neck dissection for N+ disease. Tissues were submitted for histopathologic examination and were oriented for the pathologist as to the oncologic levels so as to permit correlation between histopathologic findings and the imaging results., Results: The sensitivity and specificity of the PET/CT procedure were 79% and 82% for the N0 neck, and 95% and 25% for the N+ neck. One hundred ninety-two (11.4%) of the 1,678 nodes identified at histopathology were positive for metastases. The overall nodal sensitivity and specificity were 48% and 99%, respectively., Conclusion: In patients with clinically negative necks, a negative test would not help the surgeon in the management strategy of the patient because of the rate of false-negative results, but a positive test can diagnose metastatic deposits with a high positive predictive value. In patients with clinically positive necks, a positive test will confirm the presence of disease, although false-negative lymph nodes were additionally identified in these clinically positive necks. With respect to nodes, the sensitivity of the imaging procedure is such that the results could not help the surgeon in deciding which level to dissect and which to spare. In the final analysis, the head and neck oncologic surgeon should not depend on the results of the PET/CT scan to determine which patients will benefit from neck dissection. Rather, time-honored principles of neck surgery should be followed, particularly with regard to the liberal execution of prophylactic neck dissections in patients with clinically N0 necks.

Purpose: The workup for oral malignancy involving the mandible typically involves a head and neck exam, laboratory studies, a panoramic radiograph, and computed tomography (CT) or magnetic resonance imaging of the head and neck to evaluate the primary lesion and cervical lymph nodes. Panoramic plain film radiography of the mandible is often unreliable for detecting bony invasion; therefore, other imaging studies are necessary before staging is complete. Bony invasion is typically imaged with the use of conventional CT scanners. In this article we relate the use of cone beam computed tomography (CBCT) to image the mandible with less cost and morbidity to the patient and its use in the evaluation and treatment planning of mandibular cancer., Materials and Methods: A retrospective review of 3 patients with mandibular malignancies was performed. All patients had a panoramic radiograph, magnetic resonance imaging, and chest radiograph, in addition to laboratory studies. CBCT scans were ordered, after bony involvement was suspected, and compared with the other imaging studies., Results: Two patients with squamous cell carcinoma of anterior mandible and 1 patient with osteogenic sarcoma were reviewed. In all cases CBCT aided the evaluation of the mandible. The cone beam panoramic view, as part of the CBCT, was used to determine extent of resection., Conclusion: CBCT can accurately aid in evaluating and treatment planning for malignant tumors of the mandible with less cost and decreased radiation to the patient relative to conventional CT.

Background: Mandibular resections are routinely carried out for achieving a R0 resection for oral cancers. However, the need of mandibular resection to achieve this has always been questioned. The present study was carried out to define the pattern of mandibular involvement in carcinoma of the mandibular region., Patients and Methods: A total of 25 consecutive patients who had undergone mandibular resection and were found to have mandibular invasion were studied in a prospective open fashion. After decalcification the specimens were serially sectioned at 1 cm interval to identify invasion of mandibular bone. Type of invasion, route of spread and host cell reactions were also recorded., Results: The mandibular involvement was infiltrative in 14(56%) and erosive in 11(44%). It was cortical in 5(20%), marrow involvement was seen in 15(60%) while 5(20%) had spread through the inferior alveolar canal. Of the 25, 24(96%) lesions were located with in 1 cm of the mandible., Conclusion: The possibility of mandibular involvement is higher in patients where tumours are located with in 1 cm of the mandible. Involvement of mandible through the canal of inferior alveolar nerve in the present study was relatively high (20%). Therefore it is recommended that before a decision is taken to preserve the mandible it should be thoroughly screened for possible involvement.

High percentages (35-78%) of resected mandibles without bone invasion have been reported in squamous cell carcinoma (SCC), adjacent or fixed to the mandible, stressing the need for accurate imaging methods. The aim of this study is to determine the value of bone single photon emission computed tomography (SPECT) for the evaluation of mandibular invasion by SCC. Seventy-nine patients with SCC, adjacent or fixed to the mandible, were included. The results of bone SPECT were compared to the histology of the resection specimens. Bone SPECT was positive in all 50 patients with mandibular invasion and negative in 17 of 29 patients without mandibular invasion. In conclusion, a negative bone SPECT rules out mandibular invasion. Important clinical implications are then that further imaging is not necessary and that the resection can be kept limited. Inclusion of SPECT in the preoperative assessment of these patients will lead to a considerable reduction of unnecessary mandibular resections.

A new guide for mandibular resection in the management of oral squamous cell carcinoma based on the Cawood and Howell classification of the jaws is suggested. This was a retrospective review of case records and pre-operative orthopantomograms (OPG), bone scintigraphy and magnetic resonance imaging (MRI). The classification of the mandible was based on the residual bone height as measured in the molar region of the OPG to be equivalent to the Cawood and Howell classification of the mandible (Class I-II dentate or immediate post-extraction), Class III-IV >20mm well-rounded or knife-edge ridge, and Class V-VI <20mm (flat or depressed ridge form). Of the 77 patients, 58% (22/38) of Class I-II, 43% (9/23) of Class III-IV and 6% (1/16) of Class V-VI were treated with a marginal (rim) resection of the mandible. The predictability of the pre-operative investigations was more accurate in the edentulous mandible (Class III-VI). A simple guide is suggested for mandibular resection taking into account the pre-operative investigations, the estimation of invasion clinically, and the Cawood and Howell classification of ridge resorption.

Purpose: This study examined patterns of invasion of lower gingiva cancer into the mandible. Our goal was to clarify the most common routes for gingival squamous cell carcinoma to enter and spread within the mandible., Patients and Methods: The subjects were 176 patients with lower gingival squamous cell carcinoma who underwent mandibulectomy; all tumors were examined histopathologically. The method of mandibulectomy was decided on the basis of conventional plain radiographic and computed tomographic findings., Results: The tumor extended to the periosteum in 33%, to the cortical bone in 23%, and to the bone marrow in 9% of the patients who underwent mandibular resection. The remaining 35% of our patients had no evidence of mandibular invasion., Conclusion: The area of bone resorption on preoperative clinical and radiographic examinations often disagreed with the extent of mandibular invasion on histopathologic examination.

Primary intraosseous carcinoma of the mandible is rare, and when it occurs often arises within or closely associated with an odontogenic cyst. The purpose of this article is to show the role of computed tomography (CT) in the early detection of carcinomatous changes, because of its specificity in establishing the nature of the lesion. An unusual case of a squamous cell carcinoma that arose in an odontogenic cyst is described. The appearance on the panoramic radiograph was suggestive of a benign cystic lesion in the left side of the mandible, but when a CT scan was performed, the appearance of the lesion was compatible with malignancy. Histopathological analysis confirmed the suspicion of a squamous cell carcinoma, but without CT investigation it would be impossible to demonstrate that carcinomatous change had developed from a cystic lesion.

There has been a great deal of controversy regarding the appropriate method of management of oral cavity and oropharyngeal tumors that invade the mandible. The inability to acquire intraoperative bone margins can make the decision process complex. Preoperative imaging offers several advantages, however, there is no single modality that has proven accurate. Intraoperative assessment has been suggested as a method of evaluation, however, this approach does not allow for preoperative planning. The following is a review of the current literature regarding mandibular invasion and the indications for a marginal mandibulectomy.

The aim of this work was to compare the potential of computed tomography angiography (CTA) with that of digital subtraction angiography (DSA) in vascular mapping of the external carotid artery (ECA) branches for planning of microvascular reconstructions of the mandible with osteomyocutaneous flaps. In 15 patients CTA and DSA were performed prior to surgery. Selective common carotid angiograms were acquired in two projection for both sides of the neck. Sixteen-slice spiral computed tomography was performed with a dual-phase protocol, using the arterial phase images for 3D CTA reconstruction. Thin-slab maximum intensity projections and volume rendering were employed for postprocessing of CTA data. The detectability of the different ECA branches in CTA and DSA was evaluated by two examiners. No statistically significant differences between CTA and DSA (p=0.097) were found for identifying branches relevant for microsurgery. DSA was superior to CTA if more peripheral ECA branches were included (P=0.030). CTA proved to be a promising alternative to DSA in vascular mapping for planning of microvascular reconstruction of the mandible.

Purpose: The study goal was to investigate the adequacy of marginal resection of the mandibular bone in cases of squamous cell carcinomas of the lower alveolus and gingiva where the radiologically detected bone defect does not extend beyond the mandibular canal., Patients and Methods: Sixty-two patients who have had a mandibulectomy performed with or without preoperative radiotherapy and chemotherapy were the study subjects. This retrospective study investigated the correlation between the preoperative radiographic appearance and histopathologic findings of the excised tissue. The results of the treatments were evaluated., Results: In the cases with erosive bone defects, the extent of the bone involvement did not exceed the extent of the radiographically detected bone defects. However, in 7 (36.8%) of the cases with moth-eaten type bone defects, the extent of bone involvement exceeded the bone defects detected by radiography. Further, 10 of the 16 cases with no apparent bone defect showed apparent bone involvement by the tumors histologically. There were no differences in the 5-year cumulative survival rate between the marginal resection and segmental groups., Conclusions: Marginal resection was effective in controlling mandibular alveolus and gingival cancers when radiologically detected erosive bone defects did not extend beyond the mandibular canal. Marginal resection was inadequate when moth-eaten defects were radiologically detected, except when the bone defects were confined to the alveolar bone.

Objectives: To evaluate the significance of mandibular bone invasion by gingival carcinoma revealed by reformatted dental CT images as a prognostic indicator of cervical metastasis., Methods: Thirty-two patients with squamous cell carcinoma of the lower gingiva were examined by dental CT. Cervical metastases and survival rates of these patients were analysed in relation to their clinical characteristics, histologic grading based on gingival biopsy, and mandibular bone invasion using reformatted dental CT imaging diagnoses prior to surgery. The dental CT images were classified into four types: Class I, no bone invasion; Class II, invasion confined to the alveolus; Class III, invasion extending between the alveolus and the mandibular canal; and Class IV, invasion beyond the mandibular canal., Results: Logistic multivariate regression analysis showed that bony invasion identified on dental CT images was a significant prognostic factor in cervical metastases (P=0.028). The 5-year overall survival rates of Classes I, II, III, and IV were 100% (n=9), 76.2% (n=9), 71.4% (n=7), and 28.6% (n=7), respectively., Conclusions: The evaluation of mandibular bone invasion using dental CT images is useful as a prognostic indicator of cervical metastasis for patients with gingival carcinoma.

Squamous cell carcinoma arising in a dentigerous cyst is a rare lesion with distinct histopathology and stringent criteria for diagnosis.(1,2) During the past century, <60 cases have been reported.(3) Of the previously documented cases, all have occurred in adults. We present the case of a squamous cell carcinoma arising in a dentigerous cyst in a 16-month-old girl. This case poses interesting questions regarding the pathophysiology of these tumors and highlights the importance of maintaining a high index of suspicion regardless of age when evaluating cystic lesions of the mandible and maxilla.

The method of conservative (rim) resection of the mandible is now well established and provides good control of disease in the primary site. There are few audits of this technique in terms of margins of resection for both rim and segmental resection of the mandible. Consecutive previously untreated patients managed with resection of the mandible as part of their treatment for oral and oropharyngeal squamous cell carcinoma were recruited for the study. The presence and extent of tumour invasion of the mandible was recorded and a retrospective analysis made to establish the incidence of unnecessary segmental resections. The invasion rate was 33% (8/35) for rims and 83% (54/65) in segmental resections of the mandible, which compares favourably with previous studies and indicates a reasonable accuracy of resection. In between 6 and 11 of the 62 cases (10-17%) a rim resection could have achieved a satisfactory resection margin and retained a functioning lower border of the mandible. The accuracy of resection in terms of margins was greater for mandibular resections (94% clear margins) than soft tissues (62% clear margins). The number of compromised margins was significantly greater in the invaded rim resection group (P=0.018). This study indicates that a more conservative mandibular resection was possible in a few cases. This is unlikely to have an adverse effect on the close or involved margin rate, which depends mainly on the accuracy of the soft tissue resection. Angling the horizontal rim resection to take into account tumour entry at the point of contact will help to ensure a clear bone margin if a conservative approach to mandibular resection is an option.

The accuracy of clinical examination, peroperative periosteal stripping and imaging techniques in predicting tumour invasion of the mandible in oral cancer so far reported have been compared according to their specificity and sensitivity. Clinical examination alone was not shown to be accurate, but periosteal stripping at the time of resection was extremely accurate although so far only one study has investigated it. No single imaging technique will accurately predict the invasion of tumour into the mandible, but a combination of an orthopantomogram and bone scintigraphy is recommended in early invasion. Magnetic resonance imaging is more sensitive than computed tomography and therefore may be more useful if mandibular invasion requires consideration. The decision to resect the mandible as part of the management of oral cancer should be taken on the evidence of clinical examination, periosteal stripping and at least two imaging techniques that complement each other in terms of specificity and sensitivity., (Copyright 2001 The British Association of Oral and Maxillofacial Surgeons.)

Introduction: The role of marginal mandibulectomy and other conservative resective procedures for patients with early cortical mandibular invasion from squamous carcinoma of the oral cavity remains poorly defined. The purpose of this retrospective study was to evaluate the efficacy of preoperative assessment for bone invasion and the outcomes of different mandibular resective procedures that preserve mandibular continuity., Methods: The charts of 222 patients treated at the University of Texas M. D. Anderson Cancer Center between 1960 and 1990 were reviewed. All patients had a biopsy-confirmed diagnosis of squamous carcinoma involving either the lower gingiva, floor of mouth, oral tongue, or retromolar trigone. All patients had a surgical resection that involved removing less than a segment of the mandible. Patient data were analyzed to determine the usefulness of preoperative assessment and outcomes of therapy., Results: Clinical evaluation of mandibular bone invasion was more sensitive than radiologic evaluation, whereas radiologic assessment was more specific and had a higher reliability index. The overall local and regional recurrence and distant metastasis rates for all T stages were 14.4%, 18.0%, and 2.7%, respectively. Sixty-nine point eight percent of all patients were without evidence of disease 2 years after treatment., Conclusions: Mandibular conservation surgery is oncologically safe for patients with early mandibular invasion. Accurate preoperative assessment that combines clinical examination and radiographic evaluation is better than either modality alone, but clinical judgment is still necessary for proper patient selection., (Copyright 2001 John Wiley & Sons, Inc.)