Skull Base Invasion Research Articles

Deep learning model using planar whole-body bone scintigraphy for diagnosis of skull base invasion in patients with nasopharyngeal carcinoma

PurposeThis study assesses the reliability of deep learning models based on planar whole-body bone scintigraphy for diagnosing Skull base invasion (SBI) in nasopharyngeal carcinoma (NPC) patients.MethodsIn this multicenter study, a deep learning model was developed using data from one center with a 7:3 allocation to training and internal test sets, to diagnose SBI in patients newly diagnosed with NPC using planar whole-body bone scintigraphy. Patients were diagnosed based on a composite reference standard incorporating radiologic and follow-up data. Ten different convolutional neural network (CNN) models were applied to both whole-image and partial-image input modes to determine the optimal model for each analysis. Model performance was assessed using the area under the receiver operating characteristic curve (AUC), calibration, decision curve analysis (DCA), and compared with expert assessments by two nuclear medicine physicians.ResultsThe best-performing model using partial-body input achieved AUCs of 0.80 (95% CI: 0.73, 0.86) in the internal test set, 0.84 (95% CI: 0.77, 0.91) in the external cohort, and 0.78 (95% CI: 0.73, 0.83) in the treatment test cohort. Calibration curves and DCA confirmed the models’ excellent discrimination, calibration, and potential clinical utility across internal and external datasets. The AUCs of both nuclear medicine physicians were lower than those of the best-performing deep learning model in external test set (AUC: 0.75 vs. 0.77 vs. 0.84).ConclusionDeep learning models utilizing partial-body input from planar whole-body bone scintigraphy demonstrate high discriminatory power for diagnosing SBI in NPC patients, surpassing experienced nuclear medicine physicians.

Intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) combined with conventional MRI for the detection of skull-base invasion in nasopharyngeal carcinoma: comparison with 18F-sodium fluoride (18F-NaF) positron emission tomography/computed tomography (PET/CT).

The extent of skull base invasion (SBI) in nasopharyngeal carcinoma (NPC) directly impacts tumor staging, treatment strategies, and prognosis assessment for NPC patients, emphasizing the critical need for prompt diagnosis and precise assessment of invasion. Thus, we aimed to integrate the advantages of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and conventional magnetic resonance imaging (cMRI), and assess their combined diagnostic efficacy versus that of 18F-sodium fluoride (18F-NaF) positron emission tomography/computed tomography (PET/CT) for detecting SBI in NPC patients. The study prospectively and randomly recruited 62 patients newly diagnosed with NPC by pathological biopsy at the Cancer Center of Affiliated Hospital of Guangdong Medical University from January 2021 to September 2022. All patients underwent baseline cMRI, IVIM-DWI, and PET/CT scans. The IVIM-DWI analysis included 3 primary parameters: true diffusion coefficient (D), pseudodiffusion coefficient (D*), and pseudodiffusion fraction (f). SBI was defined as the involvement of any substructure confirmed by follow-up MRI and clinical symptoms. Inter-observer agreement was evaluated utilizing the intraclass correlation coefficients (ICC) and kappa coefficients. Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic performance of cMRI, IVIM-DWI plus cMRI, and PET/CT. DeLong test was used to compare the areas under the curve (AUC) of the 3 modalities. Excellent inter-observer reliability was observed (range, 0.841-0.946). Among the IVIM-DWI parameters, D* + f demonstrated comparable accuracy to D + D* + f (AUC 0.906 vs. 0.904; sensitivity 88.9% vs. 89.8%; specificity 92.3% vs. 91.0%). IVIM-DWI plus cMRI yielded an overall AUC of 0.947, sensitivity of 92.6%, and specificity of 96.8%, surpassing cMRI alone with an AUC of 0.914 (P=0.025), sensitivity of 91.2%, and specificity of 91.7%, as well as 18F-NaF PET/CT with an AUC of 0.852 (P<0.001), sensitivity of 80.1%, and specificity of 90.4%. In detecting substructures of SBI, IVIM-DWI plus cMRI showed superior performance compared to 18F-NaF PET/CT within the petrous part of the temporal bone (AUC 0.968 vs. 0.871, P=0.011; sensitivity 93.5% vs. 87.1%, specificity 100% vs. 87.1%), pterygopalatine fossa (AUC 0.935 vs. 0.831, P=0.032; sensitivity 93.9% vs. 69.7%, specificity 93.1% vs. 96.6%), and foramen ovale (AUC 0.885 vs. 0.710, P=0.019; sensitivity 76.9% vs. 61.5%, specificity 100% vs. 80.6%). IVIM-DWI plus cMRI can accurately detect SBI and the substructures in NPC, providing a valuable reference for personalized treatment strategies and precise prognosis assessment.

Novel insights into the classification of Shamblin III carotid body tumors from a neurosurgical perspective

Background and purposeThe classic Shamblin system fails to provide valuable guidance in many Shamblin’s III carotid body tumors (III-CBTs) due to the variable forms of carotid arteries and the complex anatomic relationships in parapharyngeal space. We proposed a modified classification to separately divide III-CBTs into different subgroups on the basis of arterial relevant features and anatomical relevant features.Materials and methodsFrom 2020 to 2023, a total of 129 III-CBTs at a single institution were retrospectively analyzed. All cases were independently classified as arterial-relevant and anatomical-relevant subgroups. The pre-, peri- and postoperative data were summarized and compared accordingly.ResultsAmong the 129 cases, 69 cases were identified as “Classical type”, 23 cases as “Medial type”, 27 cases as “Lateral type” and 10 cases as “Enveloped type” according to arterial morphologies. Besides, 76 cases were identified as “Common type”, 15 cases as “Pharynx- invasion type”, 18 cases as “Skull base-invasion type” and 20 cases as “Mixed type” according to anatomical relationships. “Enveloped type” of tumors in arterial-relevant classification and “Mixed type” of tumors in anatomical-relevant classification are the most challenging cases for surgeons with the lowest resection rate, highest incidence of carotid arteries injury and postoperative stroke.ConclusionThe modified classifications provide comprehensive understanding of different III-CBTs which are applicable for individualized treatment in clinical practice.

Neoadjuvant Chemotherapy Alone or Combined with EGFR-Directed Targeted Therapy or Anti-PD-1 Immunotherapy for Locally Advanced Lacrimal Sac and Nasolacrimal Duct Carcinomas

ABSTRACT Background/aims We describe our findings in patients with locally advanced lacrimal sac and nasolacrimal duct (NLD) carcinoma who received neoadjuvant systemic therapy. Methods We identified patients with locally advanced primary lacrimal sac/NLD carcinoma treated with neoadjuvant systemic intravenous therapy at our institution during 2017–2019. Results The study included seven patients, four men and three women; the mean age was 60.4 years (range: 43–76). All patients had locally advanced disease with significant orbital soft tissue invasion with or without skull base invasion making eye-sparing surgery not feasible as an initial step. Three patients had poorly differentiated squamous cell carcinoma; two, invasive carcinoma with basaloid and squamous features; one, high-grade carcinoma with features suggestive of sebaceous differentiation; and one, undifferentiated carcinoma. The neoadjuvant regimens were cisplatin and docetaxel (n = 1); carboplatin and docetaxel (n = 1); paclitaxel and cetuximab (n = 1); carboplatin, paclitaxel, and cetuximab (EGFR inhibitor) (n = 2); cisplatin, docetaxel, and pembrolizumab (anti-PD-1 immunotherapy) (n = 1); and carboplatin, paclitaxel, and pembrolizumab (n = 1). All patients had radiologic disease regression, and one patient had radiologic near-complete response. After neoadjuvant therapy, all patients underwent wide local excision and adjuvant concurrent chemoradiation. Two patients had a complete pathologic response. At a median follow-up period of 13 months after chemoradiation (range, 8–54 months), all patients were alive without evidence of disease. One patient had nodal metastasis treated with lymph node dissection and adjuvant chemoradiation. Conclusions Neoadjuvant systemic therapy can shrink tumors in patients with locally advanced primary lacrimal sac/NLD carcinoma with orbital or skull base invasion.

Diagnosis of skull-base invasion by nasopharyngeal tumors on CT with a deep-learning approach

PurposeTo develop a convolutional neural network (CNN) model to diagnose skull-base invasion by nasopharyngeal malignancies in CT images and evaluate the model’s diagnostic performance.Materials and methodsWe divided 100 malignant nasopharyngeal tumor lesions into a training (n = 70) and a test (n = 30) dataset. Two head/neck radiologists reviewed CT and MRI images and determined the positive/negative skull-base invasion status of each case (training dataset: 29 invasion-positive and 41 invasion-negative; test dataset: 13 invasion-positive and 17 invasion-negative). Preprocessing involved extracting continuous slices of the nasopharynx and clivus. The preprocessed training dataset was used for transfer learning with Residual Neural Networks 50 to create a diagnostic CNN model, which was then tested on the preprocessed test dataset to determine the invasion status and model performance. Original CT images from the test dataset were reviewed by a radiologist with extensive head/neck imaging experience (senior reader: SR) and another less-experienced radiologist (junior reader: JR). Gradient-weighted class activation maps (Grad-CAMs) were created to visualize the explainability of the invasion status classification.ResultsThe CNN model’s diagnostic accuracy was 0.973, significantly higher than those of the two radiologists (SR: 0.838; JR: 0.595). Receiver operating characteristic curve analysis gave an area under the curve of 0.953 for the CNN model (versus 0.832 and 0.617 for SR and JR; both p < 0.05). The Grad-CAMs suggested that the invasion-negative cases were present predominantly in bone marrow, while the invasion-positive cases exhibited osteosclerosis and nasopharyngeal masses.ConclusionsThis CNN technique would be useful for CT-based diagnosis of skull-base invasion by nasopharyngeal malignancies.

Refining the 8th edition TNM classification for EBV related nasopharyngeal carcinoma

The AJCC/UICC TNM classification describes anatomic extent of tumor progression and guides treatment decisions. Our comprehensive analysis of 8,834 newly diagnosed patients with non-metastatic Epstein-Barr virus related nasopharyngeal carcinoma (NPC) from six Chinese centers indicates certain limitations in the current staging system. The 8th edition of the AJCC/UICC TNM classification inadequately differentiates patient outcomes, particularly between T2 and T3 categories and within the N classification. We propose reclassifying cases of T3 NPC with early skull-base invasion as T2, and elevating N1-N2 cases with grade 3 image-identified extranodal extension (ENE) to N3. Additionally, we suggest combining T2N0 with T1N0 into a single stage IA. For de novo metastatic (M1) NPC, we propose subdivisions of M1a, defined by 1-3 metastatic lesions without liver involvement, and M1b, characterized by >3 metastatic lesions or liver involvement. This proposal better reflects responses of NPC patients to the up-to-date treatments and their evolving risk profiles.

The value of color doppler ultrasonography combined with computed tomography angiography and magnetic resonance angiography in the preoperative quantification and classification of carotid body tumors: a retrospective analysis

BackgroundComputed tomography angiography (CTA) and magnetic resonance angiography (MRA) provide accurate vascular imaging information, but their use may be contraindicated. Color Doppler ultrasonography (CDU) provides simple, safe, noninvasive, and reproducible imaging. We therefore investigated the role of preoperative CDU combined with CTA and MRA in the quantification, typing, and diagnosis of carotid body tumors (CBTs).MethodsWe retrospectively analyzed patients with CBTs categorized into group A (type I [n = 1] and type II [n = 10]) or group B (type III [n = 56]) per the intraoperative Shamblin classification. CDU, CTA, and MRA characteristics of CBTs were observed, surgical results were correlated, and the diagnostic threshold of the CBT classification was calculated.ResultsCBTs were usually located at the common carotid artery bifurcation, encircling the carotid artery. An increased angle was found between the internal and external carotid arteries. On CDU, CBTs primarily presented as homogeneous hypoechoic masses with clear boundaries, rich flow signals, and a high-speed, low-resistance artery-like flow spectrum. CTA showed uniform or heterogeneous marked enhancement. MRA showed mixed T1 and slightly longer T2 signals and uniform or uneven obvious enhancement. With increases in the lesion size, amount of blood transfused, and operation time, the intraoperative classification level and possibility of skull-base invasion increased. When the maximum diameter of the lesion, the volume of the tumor, the distance between the upper margin of the tumor to the mastoid and the mandibular angle were 3.10 cm, 10.15 cm3, − 3.26 cm, and 0.57 cm, respectively, the largest Youden index was the best diagnostic boundary value for Shamblin type III tumors.ConclusionsCDU combined with CTA and MRA can accurately evaluate the size and classification of CBTs.

An unusual ectopic thyroid tissue location & review of literature

Ectopic thyroid is well-known pathology for several decades. Many locations have been described. Nowadays, only three cases of skull base location have been described in literature. In our case, we reported a single case of a 39-year-old male presenting with a supra-sellar and suprachiasmatic location. He presented no clinical symptoms, no endocrine alteration on biology and no skull base invasion which make this case unique compared to actual literature. Such diagnosis should always be an exclusion diagnosis as secondary neoplastic should be first ruled out.

Dual-energy CT for the detection of skull base invasion in nasopharyngeal carcinoma: comparison of simulated single-energy CT and MRI

BackgroundSkull base invasion in nasopharyngeal carcinoma (NPC) was shown to be a poor negative prognostic factor, and dual-energy CT (DECT) has heralded a new approach to detect this condition. The study aims to evaluate the value of DECT for detection of skull base invasion in NPC and compare the diagnostic performance of DECT with those of simulated single-energy CT (SECT) and MRI.MethodsThe imaging findings of 50 NPC patients and 31 participants in control group which underwent DECT examinations were assessed in this retrospective study. The skull base invasions were evaluated using 5-point scale by two blind observers. ROC analysis, Mcnemar test, paired t test, weighted K statistics and intraclass correlation coefficient were performed to evaluate the diagnostic performance of simulated SECT, MRI and DECT.ResultsQuantitative analysis of DECT parameters showed higher normalized iodine concentration and effective atomic number values in sclerosis and lower values in erosion than those in normal bones (both p < 0.05). Compared with simulated SECT and MRI, the diagnostic sensitivity for DECT was significantly improved from 75% (simulated SECT) and 84.26% (MRI) to 90.74% (DECT) (both p < 0.001), specificity from 93.23% and 93.75% to 95.31 (both p < 0.001), accuracy from 86.67% and 90.33% to 93.67%, and AUC from 0.927 and 0.955 to 0.972 (both p < 0.05), respectively.ConclusionsDECT demonstrates better diagnostic performance than simulated SECT and MRI for detecting skull base invasions in NPC, even those slight bone invasions in early stage, with higher sensitivity, specificity and accuracy.Graphical

Systematic Review of Management and Survival Outcome of Parotid Cancers with Lateral Skull Base Invasion.

Lateral skull base involvement from parotid cancers is a rare condition and is considered a poor prognostic indicator. The aim of this study was to systematically review the literature of parotid tumors with temporal bone invasion to analyze the survival outcome. A systematic literature review was performed in August 2022, without time limits, and 289 patients affected by parotid gland cancers and lateral skull base involvement were included. The most common symptoms in parotid tumors at the onset were indolent mass, facial weakness, pain, and hearing loss; the chi-square value is 23.1063, with a statistically significance (p = < 0.000121). The five most common histologies were adenoid cystic carcinoma, acinic cell carcinoma, mucoepidermoid carcinoma, adenocarcinoma, and squamous cell carcinoma. The facial nerve function after surgery showed statistically significance (functional vs. non-functional; chi-square was 91.7698, p = < 0.00001). Mean follow-up was 36.2 months (range 0.3-192). At the last follow-up, more patients died of disease (DOD; 60/289, 21%) than other causes (DOOC; 5/289, 2%). There is a statistically significant correlation between patients died for tumor (DOD) and patients died for other causes (DOOC) (p = < 0.0001), suggesting that the lateral skull base invasion negatively impacts on survival. Basing on the results of our systematic review, lateral skull base involvement from parotid recurrent/advance tumors should be considered a poor prognostic factor, as the majority of patients die due to this condition. It also would be necessary to have "clear"works, with full data (demographic, clinical, surgical data), and with a longer follow up, in order to assess the best treatment modality of these patients.

Feasibility evaluation of intravoxel incoherent motion diffusion-weighted imaging in the diagnosis of skull-base invasion in nasopharyngeal carcinoma.

Objective: This study aimed to evaluate the feasibility of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) in the diagnosis of skull-base invasion (SBI) in nasopharyngeal carcinoma (NPC). Materials and methods: A total of 50 patients pathologically diagnosed with NPC and a group of 40 controls comprised of those with either normal nasopharynx or patients with nasopharyngitis underwent conventional MRI and IVIM-DWI scans with 3 different groups of b values. Among the 50 patients, 36 patients diagnosed with SBI in NPC were included in the case group according to SBI criteria. All subjects (including those in the control group and case group) were divided into the b1, b2, and b3 groups based on their b values. The pure diffusion coefficient (D), perfusion-related incoherent microcirculation (D*), and microvascular volume fraction (f) values obtained in each measurement area of each group were tested for variance. Next,2 groups of b-value parameters with statistically significant data in the 3 groups were randomly selected for use in both the control group and the case group. A t-test was performed on the D, D*, and f values obtained by measuring each area of the skull base, and the area under the curve (AUC) of the receiver operating characteristic (ROC) was used to evaluate the diagnostic efficacy of the D, D*, and f values. Results: There was no statistical significance among the D, D*, and f values of the b1 and b3 groups (P>0.05), and the differences in parameters between the b1 and b2 groups were statistically significant(P < 0.05),and the differences in parameters between the b3 and b2 groups were also statistically significant(P < 0.05).The f value of the case group, which was obtained using the b1 and b2 parameters in each area of the skull base, was lower than that of the control group (P <0.05).The D, D*, and f values of the case group obtained by the b1 and b2 parameters in the pars petrosa of the temporal bone (including the foramen lacerum) were lower than those of the control group (P<0.05).When the parameters of the b1 group were used in the corpus of sphenoid bone (including the foramen ovale), the D, D*, and f values of the control group and the case group were compared, yielding a statistically significant difference (P<0.05).When the parameters of the b1 group were used, the diagnostic efficacy of the f value in each area of the skull base was the highest (AUC=0.908-0.991), followed by the D* value (AUC=0.624-0.692). Conclusion: When the number of b values <200 s/mm2 in IVIM-DWI accounts for more than half of the selected b values, IVIM-DWI is highly stable for the diagnosis of SBI in NPC. The D, D*, and f values of the bone and muscle areas of the skull base in patients with SBI of NPC showed a downward trend, and the f value had the best diagnostic performance, followed by the D* value, while the D value had the worst. Thus, IVIM-DWI can be used as a noninvasive method in the diagnosis of SBI in NPC.

Impact of salvage surgery for recurrent sinonasal cancers with skull base and intracranial involvement.

Patients with recurrent sinonasal cancers (RSNCs) often present with extensive involvement of the skull base and exhibit high rates of subsequent recurrence and death after therapy. The impact of salvage surgery and margin status on progression-free survival (PFS) and overall survival (OS) has yet to be demonstrated. The goal of this study was to determine whether skull base resection with negative margins has an impact on outcomes in the recurrent setting. A retrospective chart review of 47 patients who underwent surgery for RSNC with skull base invasion between November 1993 and June 2020 was conducted. The following variables were extracted from the clinical records: patient demographic characteristics (age and sex), tumor pathology, dural and orbital invasion, and prior radiation exposure and induction chemotherapy. Metastatic disease status, surgical approach, margin status, and history of postoperative chemotherapy and/or postoperative radiation therapy were noted. The primary and secondary outcomes were PFS and OS, respectively. The cohort included 30 males (63.8%) and 17 females (36.2%), with a mean ± SD age of 54.8 ± 14.4 years. Thirty-five (74.5%) patients showed disease progression, and 29 (61.7%) patients died during the study period. The mean ± SD patient follow-up period was 61.8 ± 64.4 months. Dural invasion was associated with increased risk of death (HR 2.62, 95% CI 1.13-6.08). High-risk histopathology (HR 3.14, 95% CI 1.10-8.95) and induction chemotherapy (HR 2.32, 95% CI 1.07-5.06) were associated with increased odds of disease progression. When compared to patients with positive margins or gross-total resection with unknown margin status, those with negative margins had decreased odds of disease progression (HR 0.30, 95% CI 0.14-0.63) and death (HR 0.38, 95% CI 0.17-0.85). RSNCs show high rates of subsequent disease progression and mortality. This study demonstrated that negative margins may be associated with improved PFS and OS in carefully selected patients who have undergone salvage surgery for RSNC.

Value of skull base invasion subclassification in nasopharyngeal carcinoma: implication for prognostic stratification and use of induction chemotherapy

ObjectivesPrognoses for nasopharyngeal carcinoma (NPC) between categories T2 and T3 in the Eighth American Joint Committee on Cancer (AJCC) staging system were overlapped. We explored the value of skull base invasion (SBI) subclassification in prognostic stratification and use of induction chemotherapy (IC) to optimize T2/T3 categorization for NPC patients.MethodsWe retrospectively reviewed 1752 NPC patients from two hospitals. Eight skull base bone structures were evaluated. Survival differences were compared between slight SBI (T3 patients with pterygoid process and/or base of the sphenoid bone invasion only) and severe SBI (T3 patients with other SBIs) with or without IC using random matched-pair analysis. We calculated the prognosis and Harrel concordance index (C-index) for the revised T category and compared IC outcomes for the revised tumor stages.ResultsCompared to severe SBI, slight SBI showed better 5-year overall survival (OS) (81.5% vs. 92.3%, p = 0.001) and progression-free survival (PFS) (71.5% vs. 83.0%, p = 0.002). Additional IC therapy did not significantly improve OS and PFS in slight SBI. The proposed T category separated OS, PFS, and locoregional recurrence-free survival in T2 and T3 categories with statistical significance. An improved C-index for OS prediction was observed in the proposed T category with combined confounding factors, compared to the AJCC T staging system (0.725 vs. 0.713, p = 0.046). The survival benefits of IC were more obvious in the advanced stage.ConclusionsNPC patients with slight SBI were recommended to downstage to T2 category. The adjustment for T category enabled better prognostic stratification and guidance for IC use.Key Points• For nasopharyngeal carcinoma (NPC) patients in T3 category, slight skull base invasion was a significant positive predictor for OS and PFS.• NPC patients with slight SBI might not gain significant survival benefits from induction chemotherapy.• Downstaging slight SBI NPC patients to T2 category would make a more accurate risk stratification, improve the predicting performance in OS, and have a better guidance in the use of IC for patients in advanced stage.

Skull Base Regeneration During Treatment With Chemoradiation for Nasopharyngeal Carcinoma: A Case Report.

Advanced cases of nasopharyngal carcinoma can present with skull base invasion. Treatment of these advanced cases with radiotherapy poses a challenge given proximity of tumor to critical neural structures as well as concern that a skull base defect and associated complications could develop with tumor regression. A 34-year-old male patient presented with a 7-cm nasopharyngeal tumor invading the skull base with destruction of the clivus and intracranial extension. He underwent a course of definitive chemoradiation, requiring use of adaptive radiotherapy, that resulted in complete tumor regression and is free of disease 5 years posttreatment. Imaging done during treatment demonstrated that significant regeneration of bone occurred simultaneously with tumor regression. This case demonstrates that it is possible for bony regeneration to occur simultaneously with tumor regression in a patient with skull base invasion by tumor, precluding the need for neurosurgical intervention.

Predicting Bone Metastasis Risk Based on Skull Base Invasion in Locally Advanced Nasopharyngeal Carcinoma

ObjectiveTo develop and validate a bone metastasis prediction model based on skull base invasion (SBI) in patients with locally advanced nasopharyngeal carcinoma (LA-NPC).MethodsThis retrospective cohort study enrolled 290 patients with LA-NPC who received intensity-modulated radiation therapy in two hospitals from 2010 to 2020. Patient characteristics were grouped by SBI and hospital. Both unadjusted and multivariate-adjusted models were used to determine bone metastasis risk based on SBI status. Subgroup analysis was performed to investigate heterogeneity using a forest graph. Cox proportional hazard regression analysis was used to screen for risk factors of bone metastasis-free survival (BMFS). A nomogram of BMFS based on SBI was developed and validated using C-index, receiver operating characteristic curve, calibration curves, and decision curve analysis after Cox proportional hazard regression analysis.ResultsThe incidence of bone metastasis was 14.83% (43/290), 20.69% (24/116), and 10.92% (19/174) in the overall population, SBI-positive group, and SBI-negative group, respectively. In the unadjusted model, SBI was associated with reduced BMFS [HR 2.43 (1.32–4.47), P = 0.004], and the results remained stable after three continuous adjustments (P <0.05). No significant interaction was found in the subgroup analyses (P for interaction >0.05). According to Cox proportional hazard regression analysis and clinical value results, potential risk factors included SBI, Karnofsky performance status, TNM stage, induction chemotherapy, concurrent chemoradiotherapy, and adjuvant chemotherapy. Using a training C-index of 0.80 and a validation C-index of 0.79, the nomogram predicted BMFS and demonstrated satisfactory prognostic capability in 2, 3, and 5 years (area under curve: 83.7% vs. 79.6%, 81.7% vs. 88.2%, and 79.0% vs. 93.8%, respectively).ConclusionSkull base invasion is a risk factor for bone metastasis in patients with LA-NPC. The SBI-based nomogram model can be used to predict bone metastasis and may assist in identifying LA-NPC patients at the highest risk of bone metastasis.

A retrospective cohort study on predictors associated with skull base invasion of maxillary ameloblastomas

PurposeTo identify factors associated with skull base involvement (SBI) of maxillary ameloblastomas (MA). MethodsThis retrospective cohort study was composed of MA patients treated during a 7-year period. Demographic, radiographic, and nine immunohistopathologic predictor variables were included. The outcome variable was presence of SBI (yes/no). Descriptive, bi- and multivariate statistics were computed, and P ≤ .05 in multivariate analyses was considered statistically significant. ResultsThe sample comprised 23 subjects (34.8% females; 21.7% with SBI) with a mean age of 50.3 ± 18.2 years. Candidate predictors of an SBI in MAs were 1) male gender, 2) a low Karnofsky Performance Status score (KPS), 3) multilocular radiolucency, 4) ill-defined margins, 5) cortical perforation, 6) inclusion of an unerupted tooth, 7) moderate to strong reactivity to p53, Ki-67, CD10, astrocyte elevated gene-1 (AEG-1) protein, carbonic anhydrase IX (CA IX), calretinin (calbindin2; CALB2), and BRAF-V600E, and 8) negative to low immunopositivity to α-smooth muscle actin (α-SMA) and syndecan-1 (CD138). However, multivariate analyses confirmed the significant associations of SBI with negative/low syndecan-1 reactivity (P = .003; adjusted odds ratio [ORadj.], 4.04; 95% confidence interval [95% CI], −.89 to −.48; Pearson's Correlation Coefficient [r] = −.74) and with KPS (P = .003; ORadj., 4.04; 95% CI, −.78 to −.17; r = −.54) only. ConclusionsOur findings suggest an aggressive approach to MAs with negative to low syndecan-1 immunopositivity and/or in multi-morbid patients (who may have difficulty in access to health care). Otherwise, health care inequalities due to low KPS scores should be minimized or eliminated.

MRI Evaluation of Invasive Sinonasal Mucormycosis in Post COVID-19 Patients: A Retrospective Study

Introduction: Mucormycosis is also known as phycomycosis or zygomycosis, is caused by a saprophytic fungal infection. During the second wave of coronavirus disease-2019 (COVID- 19), secondary complication among clinically severe COVID-19 with or without diabetes was the involvement of the paranasal sinuses, rhino-orbitalocerebral, cutaneous, gastric and lungs by mucormycosis. The disease progresses rapidly within a few hours to days, causing cranial nerve palsies and intracranial spread of the disease. Early imaging is helpful in assessing the extent of the spread of the disease and complications and planning the treatment. Aim: The purpose of this study is to assess the distinct MRI findings in invasive sinonasal mucormycosis in post COVID-19 patients and also to describe the various patterns of extension. Materials and Methods: This retrospective study was carried out on post COVID patients with imaging features of invasive sinonasal mucormycosis in the rural population of Hoskote, Bangalore, who underwent MRI at MVJ Medical College and Research Hospital, Hoskote, Bangalore, India in a tertiary care center, between May 2021 to July 2021. A total of 20 patients met the inclusion criteria. The various imaging features of invasive sinonasal mucormycosis were evaluated and tabulated, along with a description of its extensions. All the data obtained from the study was compiled with Microsoft Excel (2019 version). Results: The study showed a male predominance with a mean age of 47.5 years. The most commonly involved sinus was the ethmoid sinus, seen in all 20 patients (100%), followed by a combination of the ethmoid and maxillary sinus 10 (50%). MRI showed T2W hyperintense mucosal thickening with hypointense contents within the involved sinuses in all cases, hypointensity along the turbinates and nasal septum and heterogeneous post contrast enhancement. The intraorbital extension was seen in 15 patients (75%), intracranial involvement in 4 patients (20%), bone involvement in 2 cases (10%) and pterygopalatine fossa involvement in 5 patients (25%), face involvement seen in 2 patients (10%). Conclusion: Magnetic Resonance Imaging (MRI) aids in a thorough evaluation of intracranial and soft tissue involvement, orbital, skull base invasion, perineural spread and vascular invasion. MRI demonstrates variable signal intensity depending on the sinus contents and variable enhancement patterns with a lack of enhancement due to tissue necrosis, an early finding of mucormycosis. Therefore, radiologists should be aware of the imaging findings and evaluation of the extensions, which can lead to early diagnosis and timely management, reducing the morbidity and mortality rates.

Adult Head and Neck Rhabdomyosarcoma: Management, Outcomes, and the Impact of IMRT on Locoregional Control

<h3>Purpose/Objective(s)</h3> Only 9% of adult Rhabdomyosarcomas (RMS) present with primary disease in the head and neck (HNRMS), often as a paranasal mass with proptosis, orbital and skull base invasion, and a prodigious risk of regional node involvement and distant metastatic dissemination to unusual locations in the young adult with the embryonal/alveolar (E/A) subtype. E/A-RMS respond rapidly to chemotherapy and radiotherapy (RT) and management is extrapolated from the pediatric experience where prognosis is better but treatment imperatives differ. We report on adults with HNRMS treated over 3 decades. <h3>Materials/Methods</h3> We reviewed adult patients treated from 1984 – 2017 via chart review and a prospectively maintained database from 1989 onward. RMS were categorized as embryonal/alveolar (E/A) or pleomorphic (P). Standard management was as follows: E/A-RMS were treated with neoadjuvant chemotherapy, definitive chemoradiotherapy (CRT), and then maintenance chemotherapy. Chemotherapy regimens included VAC and VAC/IE, with VC given concurrently with RT. P-RMS were treated with surgery +/- RT. IMRT was adopted from 2005 onward. <h3>Results</h3> Fifty-eight patients met inclusion criteria; median age was 32 years. Seventy-six percent of tumors (n = 45) were parameningeal and 45% (n = 26) were > 5cm. Of 45 patients with M0 disease treated with curative intent, 33 (73%) had E/A-RMS and 12 (27%) had P-RMS. All E/A-RMS patients received definitive RT with either 66 Gy or 70 Gy in 2 Gy per fraction, except 2 who had surgery for diagnostic purposes. Involved nodal regions were treated with radical dose RT and elective nodal RT was routinely delivered. In the IMRT-era, patients with primary disease in the nasopharynx or paranasal sinuses were treated with bilateral neck RT, while patients with well lateralized primary disease were generally treated with ipsilateral neck RT. Pre-IMRT, out of 23 patients with initial M0 E/A-RMS, 12 (52%) had a loco-regional recurrence. Post-IMRT, out of 10 patients with initial MO disease, only 1 (10%) had a local recurrence; this patient achieved a complete clinical response despite a 3-week interruption after 48 Gy due to local toxicity, but experienced an in-field local recurrence 45 months later that resulted in death. Locoregional control was statistically superior in the IMRT era as compared to pre-IMRT (Fisher's exact test, <i>P</i> = 0.049). Overall, distant metastasis was the predominant mode of treatment failure (n = 17/33, 52%). <h3>Conclusion</h3> In our experience, the rate of locoregional control for adult E/A-HNRMS following definitive CRT using IMRT is excellent. As such CRT should be considered the treatment of choice in this population to avoid extensive surgery including craniofacial resection and orbital exenteration, which would be needed for many of these patients but has functional and cosmetic consequence; it would also interrupt ongoing maintenance chemotherapy which has proven survival benefit. In contrast P-RMS is distinct and requires surgery +/- RT.

Two Birds with One Stone: Skull Base Meningioma and Jugulotympanic Paragangliomas with Somatostatin Receptor Positron Emission Tomography.

We describe the case of a 74-year-old female patient previously treated with radiation therapy for a meningioma of the skull base and with surgery for a right tympanic paraganglioma. After the morphological progression of the meningioma demonstrated by magnetic resonance imaging (MRI), the patient underwent somatostatin receptor positron emission tomography/computed tomography (SR-PET/CT) with Gallium-68 DOTATATE for restaging. This examination showed increased somatostatin receptor expression by the meningioma and confirmed its extension as already assessed by MRI (endocranial extension, skull base involvement and invasion of the right orbit). Furthermore, SR-PET/CT detected two small right jugulotympanic pararagangliomas with high somatostatin receptor expression. Lastly, SR-PET/CT demonstrated that this patient would be an ideal candidate for peptide receptor radionuclide therapy (PRRT) that can be used for the treatment of progressive/treatment-refractory meningiomas and relapsed paragangliomas with high somatostatin receptors expression, both conditions coexisting in this case.

Free rectus abdominis myocutaneous flap for the reconstruction of major and complex defects in the craniofacial regions after ablation of advanced sinonasal carcinomas

Objective: To explore the method and plausibility of using free rectus abdominis flap (FRAF) to reconstruct the major and complex defects in the craniofacial regions after ablation of advanced sinonasal carcinoma. Methods: From 2007 to 2018 at No. 980 Hospital of Joint Logistic Supportive Force of People's Liberation Army of China, 13 patients with advanced carcinoma of nasal cavity and paranasal sinuses, including 11 males and 2 females, aged from 33 to 67 years, were treated with FRAF to repair the invasion of skull base, face and orbit. Based on adequate and meticulous preoperative evaluations on patients and tumors, complete resection of tumor bulks was performed. According to the sites, characters and extents of the defects, FRAF was introduced in different ways into reconstruction of major and complex defects in the craniofacial regions after resection of advanced sinonasal carcinomas, restoring the structure and contour of the craniofacial region. Results: Complete resection of tumors was achieved in all cases. For repairing the major and complex defects resulted from tumor ablation, FRAF graft was conducted in 13 patients with advanced sinonasal carcinomas. The recipient vessels were facial artery and vein in 9 cases, superficial temporal artery and vein in 4 cases. Vascular bridging with the external jugular vein was carried out in 2 cases who underwent submandibular neck dissections, in which facial artery and vein were used as recipient vessels. Free fibular flap was used along with FRAF in a case undergone bilateral maxillectomy. Pedicled galea capitis and periosteal flap were applied simultaneously in 3 cases with dura defects at the skullbase resulted from tumor resection. All flaps used in 13 cases survived uneventfully without major complications, with successful repair of defects, reconstruction of structures and restoration of contour of craniofacial regions. Conclusion: With adequate evaluation of resectability of tumors as well as nature and extent of defects after tumor removal, FRAF transplantation is an ideal method and strategy of choice for reconstructing the major and complex defects in craniofacial regions resulted from tumor ablation of advanced sinonasal carcinomas.