Retromolar trigone tumors: evaluation by magnetic resonance imaging and correlation with pathological data

Underlying bone change in oral squamous cell carcinoma observed from magnetic resonance imaging and computed tomography: Potential implications for tumor aggressiveness and prognosis

Background

/purposeIn cases where oral squamous cell carcinoma (OSCC) invades the jawbone, clinicians frequently observe abnormal attenuation on computed tomography (CT) and pathologic signal intensity (SI) on magnetic resonance (MR) imaging of the affected underlying bone marrow. This study introduced a concept of "underlying bone change" to examine its association with clinicopathological features and prognosis of OSCC, as well as its correlation with medullary invasion.

Materials and methods

We enrolled 93 consecutive patients diagnosed with OSCC, who underwent mandibulectomy between 2010 and 2016. CT and MR images, along with electronic medical records, were reviewed to evaluate correlations between underlying bone changes, clinicopathological features, five-year overall survival, and medullary invasion.

Results

Of the 93 patients, 69 (74.2%) exhibited underlying bone sclerosis on CT, and 74 (79.6%) displayed pathological SI on MR images. These underlying bone changes correlated with the T stage and recurrence, but not with overall survival.Medullary invasion, observed in 61 (65.6%) patients, was strongly associated with T and TNM stages and was linked to poorer overall survival.The underlying bone changes on CT and MR images were positively associated with medullary invasion; however, no significant differences were found in the occurrence of underlying bone changes between the subtypes based on the extent of medullary invasion.

Conclusion

Underlying bone changes on CT and MR images can provide valuable insights into the aggressiveness of bone invasion by OSCC. Accurate interpretation of these imaging findings might be crucial for correctly delineating surgical margins and preventing the overestimation of tumor extent.

Surgical anatomy of the lingual nerve for palate surgery: where is located and how to avoid it

PURPOSE

To describe the anatomic relationship of the lingual nerve with the lateral oropharyngeal structures.

METHODS

An anatomic dissection of the lateral oropharyngeal wall was conducted in eight sides from four fresh-frozen cadaveric heads. Small titanium clips were placed along the lingual nerve and the most anterior and medial border of the medial pterygoid muscle. Radiological reconstructions were employed for optimal visualization; the coronal view was preferred to resemble the surgical position. The distance between the lingual nerve and the medial pterygoid muscle at its upper and lower portion was measured radiologically. The trajectory angle of the lingual nerve with respect to the pterygomandibular raphe was obtained from the intersection between the vector generated between the clips connecting the upper and lower portion of the medial pterygoid muscle with the vector generated from the lingual nerve clips.

RESULTS

The mean distance from the upper portion of the medial pterygoid muscle and superior lingual nerve clips was 10.16 ± 2.18 mm (mean ± standard deviation), and the lower area of the medial pterygoid muscle to the lingual nerve was separated 5.05 ± 1.49 mm. The trajectory angle of the lingual nerve concerning to the vector that describes the upper portion of the most anterior and medial border of the medial pterygoid muscle with its lower part was 43.73º ± 11.29.

CONCLUSIONS

The lingual nerve runs lateral to the lateral oropharyngeal wall, from superiorly-inferiorly and laterally-medially, and it is closer to it at its lower third.

MR imaging of Oral Cavity and Oropharyngeal Cancer

MR imaging is the modality of choice in the evaluation of oral cavity and oropharyngeal cancer. Routine postcontrast MR imaging is important for the accurate localization and characterization of the locoregional extension of oral cavity and oropharyngeal cancers. The anatomy of the oral cavity and oropharynx is complex; accurate interpretation is vital for description of the extension of the masses. Understanding the new changes in the eighth edition of the American Joint Committee on Cancer staging system. MR imaging is the imaging modality of choice for detection of perineural spread.

Imaging in oral cancers: A comprehensive review

This review aims at simplifying the relevant imaging anatomy, guiding the optimal imaging method and highlighting the key imaging findings that influence prognosis and management of oral cavity squamous cell carcinoma (OSCC). Early OSCC can be treated with either surgery alone while advanced cancers are treated with a combination of surgery, radiotherapy and/or chemotherapy. Considering the complex anatomy of the oral cavity and its surrounding structures, imaging plays an indispensable role not only in locoregional staging but also in the distant metastatic work-up and post treatment follow-up. Knowledge of the anatomy with understanding of common routes of spread of cancer, allows the radiologist to accurately determine disease extent and augment clinical findings to plan appropriate therapy. This review aims at simplifying the relevant imaging anatomy, guiding the optimal imaging method and highlighting the key imaging findings that influence prognosis and management.

Defining secure surgical bone margins in head and neck squamous cell carcinomas: The diagnostic impact of intraoperative cytological assessment of bone resection margins compared with preoperative imaging

BACKGROUND

Imaging provides crucial staging information for treatment planning of head and neck squamous cell carcinomas (HNSCCs). Despite technical progress in imaging techniques, defining the extent of bone involvement preoperatively remains challenging and requires intraoperative information to control for adequate resection. The intraoperative cytological assessment of the bone resection margins (ICAB) provides information whether bone is infiltrated by carcinoma. The aim of this study was to assess the diagnostic value of preoperative imaging compared with ICAB in order to achieve carcinoma-free bone margins.

MATERIALS AND METHODS

108 HNSCC patients underwent preoperative computed tomography (CT), magnetic resonance imaging (MRI) and orthopantomogram (OPG) for staging and surgical planning. Curative resection was planned based on imaging. Intraoperatively, the resection margins were controlled by ICAB. The diagnostic value of preoperative imaging and ICAB was assessed with reference to the histological findings.

RESULTS

CT showed a sensitivity of 89.7%, specificity of 63.0%, positive predictive value (PPV) of 85.9%, and negative predictive value (NPV) of 70.8%. MRI revealed a sensitivity of 45.5%, specificity of 66.7%, PPV of 71.4% and NPV of 40.0%. OPG-imaging had a sensitivity of 64.7%, specificity of 76.2%, PPV of 81.5%, NPV 57.1%. In comparison, ICAB provided a sensitivity of 78.6%, specificity of 95.7%, PPV 73.3%, and NPV 96.7%. The accuracy was 82.1%, 52.9%, 69.0%, and 93.5% for CT, MRI, OPG, and ICAB, respectively.

CONCLUSION

Preoperative imaging lacks accuracy in defining adequate bone resection margins, compared with ICAB. ICAB supports preoperative imaging and intraoperative frozen sections to improve bone margin control.

Prognostic Stratification of Patients With Advanced Oral Cavity Squamous Cell Carcinoma

PURPOSE OF REVIEW

Prognosis of advanced oral squamous cell carcinoma remains a challenge for clinicians despite progress in its diagnosis and treatment over the past decades. In this review, we assessed clinicopathological factors and potential biomarkers along with their prognostic relevance in an attempt to develop optimal treatment strategies for these patients.

RECENT FINDINGS

In addition to several pathologic factors that have been proposed to improve prognostic stratification and treatment planning in the eighth edition of the American Joint Committee staging manual on cancer, we reviewed some other imaging and clinicopathological parameters demonstrated to be closely associated with patient prognosis, along with the biomarkers related to novel target or immune therapy. Evaluation of current literature regarding the prognostic stratification used in contemporary clinicopathological studies and progress in the development of targeted or immune therapy may help these patients benefit from tailored and personalized treatment and obtain better oncological results.

MR assessment of oral cavity carcinomas

Approximately half of head and neck carcinomas arise from the oral cavity. Imaging plays an essential role in the preoperative evaluation of oral cavity carcinomas. MR imaging is particularly advantageous in the evaluation of the oral cavity, with better depiction of the anatomy in this region and reduction of dental artifacts compared with CT. MR is also the preferred imaging modality for the evaluation of bone marrow invasion and perineural tumor spread, which are findings critical for treatment planning. Advanced MR imaging techniques may potentially better delineate true tumor extent, determine lymph node metastases, and predict treatment response.

Transformation in mandibular imaging with sweep imaging with fourier transform magnetic resonance imaging

OBJECTIVE

Current imaging techniques are often suboptimal for the detection of mandibular invasion by squamous cell carcinoma. The aim of this study was to determine the feasibility of a magnetic resonance imaging (MRI)-based technique known as sweep imaging with Fourier transform (SWIFT) to visualize the structural changes of intramandibular anatomy during invasion.

DESIGN

Descriptive case study.

SETTING

Tertiary academic institution.

PATIENTS

Patients with oral carcinoma who underwent segmental mandibulectomy.

INTERVENTIONS

Two specimens from each patient were imaged using a 9.4-T Varian MRI system. The SWIFT images were correlated with histologic sections.

RESULTS

The SWIFT technique with in vitro specimens produced images with sufficient resolution (156-273 μm) and contrast to allow accurate depiction of tumor invasion of cortical and medullary bone. Both specimens had histopathologic evidence of mandibular invasion with tumor. A high degree of correlation was found between magnetic resonance images and histopathologic findings.

CONCLUSIONS

The SWIFT MRI offers 3-dimensional assessment of cortical and medullary bone in fine detail and excellent qualitative agreement with histopathologic findings. Imaging with the SWIFT MRI technique demonstrates great potential to identify mandibular invasion by oral carcinoma.

A comparative study of fused FDG PET/MRI, PET/CT, MRI, and CT imaging for assessing surrounding tissue invasion of advanced buccal squamous cell carcinoma

PURPOSE

This study aimed to evaluate the diagnostic value of fused fluorodeoxyglucose positron emission tomography and magnetic resonance imaging (PET/MRI) compared with PET/computed tomography (CT), MRI, and CT in assessing surrounding tissue invasion of advanced buccal squamous cell carcinoma (BSCC).

MATERIALS AND METHODS

PET/CT and MRI were performed in 17 consecutive patients with suspected masticator space invasion of BSCC from CT images. Attenuation-corrected PET and head and neck MRI datasets were registered. For pathologic correlation, 4 regions of interest were examined, including the maxilla, mandible, pterygoid, and masseter muscle. The tumor maximal diameter, measured by different imaging modalities, was correlated with pathology results.

RESULTS

All PET/MRI fusions were verified as well matched using specific anatomic criteria. For pathology results, 1 patient had inflammation only, 1 had spindle cell cancer, and 15 had squamous cell cancer. Of 64 regions of interest, 20 (31.3%) harbored tumor invasion. The likelihood ratio was highest in fused PET/MRI (42.56) compared with PET/CT (25.02), MRI (22.94), and CT (8.6; all P < 0.05). The sensitivity and specificity of fused PET/MRI were also highest among the 4 modalities (90.0%/90.9%, 80.0%/84.1%, 80.0%/79.5%, and 55.0%/81.8%, respectively). The level of confidence was higher in fused PET/MRI or MRI than in PET/CT or CT (85.9%, 85.9%, 70.3%, 73.4%, respectively). The maximal lesion size was 3.0 to 6.0 cm in the pathology specimen. Regression analysis showed better agreement between fused PET/MRI and pathology results.

CONCLUSIONS

Fused PET/MRI is more reliable for focal invasion assessment and tumor size delineation in advanced BSCC compared with PET/CT, MRI, and CT. PET/CT has the lowest confidence level, which may limit its use in the clinical setting.

Oral cavity and oropharyngeal squamous cell cancer: key imaging findings for staging and treatment planning

The imaging findings in squamous cell carcinoma (SCC) of the oral cavity and oropharynx vary widely, depending on the site of origin of the primary tumor and the extent of its involvement of other regions. Knowledge of the complex anatomy of the oral cavity and oropharynx, as well as the most common routes by which SCC spreads from various anatomic sites, allows the radiologist to accurately determine the extent of disease and help clinicians plan appropriate treatment. SCCs that originate in the oral cavity tend to behave differently than those that originate in the oropharynx, with the latter group exhibiting more aggressive growth. Furthermore, primary tumors in certain anatomic subsites within the oral cavity or oropharynx have a greater propensity to spread by direct extension along muscle, bone, or neurovascular bundles or to be disseminated along lymphatic drainage pathways to regional or distant nodes. Imaging findings of deep muscular, neurovascular, osseous, or nodal involvement are indicative of an advanced stage of disease for which management options are limited.

Multi-detector row computed tomography (MDCT) and magnetic resonance imaging (MRI) in the evaluation of the mandibular invasion by squamous cell carcinomas (SCC) of the oral cavity. Correlation with pathological data

BACKGROUND

To retrospectively compare the diagnostic accuracy of magnetic resonance imaging (MRI) and multidetector-row computed tomography (MDCT) in the assessment of the mandibular invasion by squamous cell carcinoma (SCC) having histopathological exams as standard of reference.

MATERIALS AND METHODS

Institutional review board approval with a waiver of informed patient consent was obtained. Of the 147 patients selected from our database who underwent surgical excision of a tumour arising into the oral cavity, thirty-six patients (26 men, 10 women; mean age, 56 years; range, 30-75 years) with hystologically proven SCC who performed both a preoperative MRI and MDCT, composed our final study population.Images were qualitatively analyzed in consensus by two expert radiologist in head and neck imaging. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were assessed for both MRI and MDCT.Differences in sensitivity, specificity, positive and negative predictive values were calculated at a statistical significance of p < .05.

RESULTS

The sensitivity, the specificity and the accuracy of MRI and MDCT in the detection of the mandibular involvement were respectively 93%, 82%, 86% and 79%, 82%, 81%, while the positive predictive value (PPV) and negative predictive value (NPV) were respectively 76%, 95% and 73%, 86%. There wasn't any statistically significant difference in overall diagnostic accuracy between MRI and MDCT in the evaluation of mandibular tumour invasion (p > .05).

CONCLUSION

MRI showed to have a higher sensitivity compare to MDCT in the assessment of mandibular involvement from SCC arising in the oral cavity although none statistically significant differences were noted.

The prediction of mandibular invasion by squamous cell carcinomas with the expression of osteoclast-related cytokines in biopsy specimens

Destruction of bone by tumour is caused by osteoclasts rather than by tumour cells directly. Tumour cells of invasive oral squamous cell carcinomas (SCC) release osteoclast-related cytokines and cytokines activate osteoclasts. The purpose of this study was to investigate the possibility of predicting mandibular invasion by SCC by analysis of the expression of osteoclast-related cytokines in biopsy specimens of SCC, adjacent or fixed to the mandible. Thirty-five biopsy specimens from the pathology archives were examined from patients who had been treated for SCC, adjacent or fixed to the mandible. The patients were divided into those with and without medullary invasion. The expression of tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-11 was studied by immunohistochemical analysis. No significant differences were found in expression of TNF-alpha, IL-6 and IL-11 between biopsy specimens with or without medullary invasion. Quantification of the density of tumour-infiltrating lymphocytes was not reproducible. In conclusion, the expression of TNF-alpha, IL-6 and IL-11 in biopsy specimens of SCC, adjacent or fixed to the mandible, is not an appropriate method for predicting the presence of medullary invasion of the mandible.

Quantitative dynamic contrast-enhanced MRI for the assessment of mandibular invasion by squamous cell carcinoma

The objective of this study was to determine the value of dynamic contrast-enhanced MRI (DCE-MRI) for the preoperative assessment of mandibular invasion in squamous cell carcinomas (SCC), adjacent or fixed to the mandible. DCE-MRI was performed with gadolinium diethylene triamine pentaacetic acid (Gd-DTPA). Data were obtained from 25 patients. From pharmacokinetic analysis of the tissue uptake of Gd-DTPA, the DCE-MRI parameters (k(ep), K(trans) and v(e)) were determined, with k(ep) representing the exchange rate constant, K(trans) the volume transfer constant and v(e) the volume of extracellular space per unit volume of tissue. The histology of the resection specimens was used as gold standard for the extent of mandibular invasion. SCC with medullary invasion showed higher mean k(ep) and K(trans) compared with SCC without medullary invasion (ANOVA, p<0.001). ROC analysis of k(ep) and K(trans) revealed reliable threshold values for medullary invasion. In conclusion, DCE-MRI can discriminate SCC with medullary invasion from SCC without medullary invasion and may serve as a valuable tool in preoperative tumour staging with regard to the delineation of medullary invasion.

T4b oral cavity cancer below the mandibular notch is resectable with a favorable outcome

According to the AJCC 2002 staging system, squamous cell carcinoma of the oral cavity (OSCC) with T4b is unresectable. Herein, we report on our surgical outcome for T4b OSCC. All patients were enrolled before 2002. From January 1996 to December 2000, 45 consecutive untreated T4b OSCC patients were included. According to the trans-axial plane of the mandibular notch on CT/MRI, seven were supra-notch T4b and 38 were infra-notch T4b tumors. Significantly higher 5-year loco-regional control and survivals were observed in patients with infra-notch T4b than with supra-notch T4b. In the infra-notch group, pN0-1 patients had a significantly higher 5-year loco-regional control and survivals than pN2 patients. Nerve invasion was the sole significant adverse factor for loco-regional control and survivals in the infra-notch T4b group with pN0-1. Our retrospective study demonstrated that OSCC patients of infra-notch T4b with pN0-1 and no nerve invasion might have a favorable surgical outcome.

Imaging of oral cavity cancer

Despite many advances in surgical techniques, technology, radiation therapy, and chemotherapy, survival rates for head and neck cancer (HNCa) have not improved significantly in decades, with many patients being diagnosed at advanced disease stages. Adequate assessment of oral cavity malignancies is critical for appropriate planning of surgical, radiation, and chemotherapy treatment. Imaging modalities used to evaluate the oral cavity include plain radiography (panoramic radiography and intraoral radiography), nuclear medicine scintigraphy, ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). This review describes these imaging techniques and their utility, primarily CT and MRI.

Bone SPECT reduces the number of unnecessary mandibular resections in patients with squamous cell carcinoma

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.

Superiorly based and island masseter muscle flaps for repairing oropharyngeal defects

INTRODUCTION

Tumours of the posterior part of the mouth and/or the oropharynx are often diagnosed at advanced stages. Reconstruction in this region has advanced considerably during the last three decades. Although microsurgery has offered major progress and has obviously improved the patients' outcome, the use of local and regional flaps generally remains an ideal solution for reconstruction.

MATERIAL AND METHODS

Between January 1994 and December 2001, the defects resulting from resection in 22 out of 38 patients with retromolar and/or anterior faucial pillar squamous cell carcinomas treated at this institution, were repaired by one of two types of masseter muscle flaps. The first type is the superiorly based or cross-over masseter muscle flap, and the second type the island muscle flap (being a modification of the first type).

RESULTS

The superiorly based masseter muscle flap was used in 12 patients and the island masseter muscle flap in 10. Both techniques offer a quick and reliable method for repairing oropharyngeal defects in oncologically "safe" cases. Neither require elaborate technique or aftercare.

CONCLUSION

The island masseter muscle flap has an advantage over the superiorly based masseteric flap, as it is more flexible, pliable for larger defects, and causes no postoperative trismus.

Tumor Volume in Pharyngolaryngeal Squamous Cell Carcinoma: Comparison at CT, MR Imaging, and FDG PET and Validation with Surgical Specimen

PURPOSE

To compare computed tomography (CT), magnetic resonance (MR) imaging, and fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) for delineation of gross tumor volume (GTV) in pharyngolaryngeal squamous cell carcinoma and to validate results with the macroscopic surgical specimen when available.

MATERIALS AND METHODS

Twenty-nine patients with stages II-IV squamous cell carcinoma treated with radiation therapy or chemotherapy and radiation therapy (n = 20) or with total laryngectomy (n = 9) were enrolled. Ten patients had oropharyngeal, 13 had laryngeal, and six had hypopharyngeal tumors. CT, MR imaging, and PET were performed with patients immobilized in a customized thermoplastic mask, and images were coregistered. GTVs obtained with the three modalities were compared quantitatively and qualitatively. If patients underwent total laryngectomy, images were validated with the surgical specimen after three-dimensional coregistration. The effect of each modality was estimated with linear mixed-effects models. Adjustments for multiple comparisons were made with the Bonferonni or Sidak method.

RESULTS

For oropharyngeal tumors and for laryngeal or hypopharyngeal tumors, no significant difference (P >.99) was observed between average GTVs delineated at CT (32.0 and 21.4 cm(3), respectively) or MR imaging (27.9 and 21.4 cm(3), respectively), whereas average GTVs at PET were smaller (20.3 [P </=.10] and 16.4 cm(3) [P </=.01], respectively). GTVs from surgical specimens were significantly smaller (12.6 cm(3), P </=.06). In nine patients for whom a surgical specimen was available, no modality adequately depicted superficial tumor extension; this was due to limitations in spatial resolution. In addition, false-positive results were seen for cartilage, extralaryngeal, and preepiglottic extensions.

CONCLUSION

Compared with GTVs at CT and MR imaging, GTVs at FDG PET were smaller. In nine patients for whom a surgical specimen was available, PET was found to be the most accurate modality. However, no modality managed to depict superficial tumor extension.

Management of cancer of the retromolar trigone

Treatment of cancer of the retromolar trigone (RMT) is controversial. While early lesions may be managed with single-modality, more advanced lesions may invade the mandible, pterygoid musculature, and the adjacent mucosa of the tonsillar pillar and soft palate, therefore making therapeutic decisions more complicated. Treatment options traditionally include surgical resection, external beam irradiation, and combined modality therapy. The choice of therapy is dependent on the extent of the tumor, nodal metastasis, and the medical status of the patient and comorbid conditions. The following review outlines the current issues relevant to the diagnosis and therapy of patients with RMT malignancy.

Treatment of squamous cell carcinoma of the anterior faucial pillar-retromolar trigone

Cancer of the anterior faucial pillar-retromolar trigone is an uncommon head and neck tumor, which has historically been shown to be associated with poor prognosis. In this retrospective study, we reviewed our experience with primary surgery followed by postoperative radiation therapy in order to determine the impact of our treatment protocols on patients' outcome. Between January 1994 and December 1998, 31 patients with histologically proven squamous cell carcinoma (SCC) of the anterior faucial pillar-retromolar trigone were treated in our department. Surgical excision of the primary lesion and ipsilateral neck dissection were performed in all patients. Reconstruction was accomplished using masseter muscle flap or tongue flap. Postoperatively, most patients (90%) received radiation therapy (51-58 Gy) to the primary side and neck. Adjuvant chemotherapy was offered if histologic signs of aggressive behavior were identified. Four out of 31 patients were initially seen at stage I or II and 27 patients at stage III or IV of the disease. Metastatic disease was demonstrated in 78% of ipsilateral neck nodes. Occult metastases were found in 64% of clinically N0 necks. The 3-year loco-regional recurrence rates were 44.8%. SCC of retromolar trigone is considered as an aggressive and insidious tumor. The reconstruction of the deficit of the anterior faucial pillar-retromolar area with masseter muscle flap is a reliable, safe and absolutely functional method.