Solid Tumors of the Mediastinum in Adults

Descriptive analysis of therapeutic outcomes between thoracoscopic and transsternal thymectomy in myasthenia gravis patients from 2011 to 2021

BACKGROUND

Myasthenia gravis is an autoimmune disease with high prevalence of thymus disorders, in which, thymectomy is considered one of the therapeutic approaches in improving the patients' clinical outcomes. Today, thoracoscopic thymectomy has received significant attention than the classic transsternal approach due to fewer complication. Therefore, this study was designed with the aim of investigating the therapeutic outcomes of thymectomy in patients with myasthenia gravis in the Afzalipour Hospital of Kerman between 2011 and 2021.

METHODS

The current study is a descriptive analytical study on patients with myasthenia gravis who underwent surgical thymectomy within 2011-2021. Demographic and clinical characteristics of patients from the time of operation to three years of follow-up were extracted and recorded from clinical records or by phone calls. Data were analyzed using SPSS software.

RESULTS

The data of 70 patients who underwent surgical thymectomy were analyzed. Thymectomy caused a significant reduction in the severity of the disease according to the Osserman classification (P = 0.001). It also significantly reduced the use of corticosteroids (P = 0.001) and IVIG (P = 0.015) compared to the time before the surgery. Sixty-two patients (88.57%) needed to take less medicine than before surgery. Left VATS was associated with less post-operative severity of the disease (P = 0.023). There were only two deaths during the follow-up period.

CONCLUSION

Overall, the findings of the present study demonstrated that thoracoscopic thymectomy is a useful surgical approach that leads to faster recovery, reducing the severity of the disease, need for medication, and complications in patients with myasthenia gravis, In comparison with the transsternal approach.

Robotic portal resection for mediastinal tumours: a prospective observational study

BACKGROUND

To demonstrate the effectiveness and feasibility of robotic portal resection (RPR) for mediastinal tumour using a prospectively collected database.

METHODS

Data from 73 consecutive patients with mediastinal tumours who underwent RPRs were prospectively collected from August 2018 to April 2023. All patients underwent chest and abdominal enhanced computed tomography (CT) and preoperative multidisciplinary team (MDT) discussion. The patients were stratified into two groups based on tumour size: Group A (tumour size < 4 cm) and Group B (tumour size ≥ 4 cm). General clinical characteristics, surgical procedures, and short outcomes were promptly recorded.

RESULTS

All of the cases were scheduled for RPRs. One patient (1/73, 1.4%) was switched to a small utility incision approach because of extensive pleural adhesion. Two patients (2.8%) converted to sternotomy, however, no perioperative deaths occurred. Most of the tumours were located in the anterior mediastinum (51/73, 69.9%). Thymoma (27/73, 37.0%) and thymic cyst (16/73, 21.9%) were the most common diagnoses. The median diameter of tumours was 3.2 cm (IQR, 2.4-4.5 cm). The median total operative time was 61.0 min (IQR, 50.0-90.0 min). The median intraoperative blood loss was 20 mL (IQR, 5.0-30.0 ml), and only one patient (1.4%) experienced an intraoperative complication. The median length of hospital stay was 3 days (IQR, 2-4 days). Compared with Group A, the median total operative time and console time of Group B were significantly longer (P = 0.006 and P = 0.003, respectively). The volume of drainage on the first postoperative day was greater in group B than in group A (P = 0.013).

CONCLUSION

RPR is a safe and effective technique for mediastinal tumour treatment, which can expand the application of minimally invasive surgery for the removal of complicated mediastinal tumours.

A diagnostic model based on 18F-FDG PET/CT parameters in improving the differential diagnosis of invasive thymic epithelial tumors and anterior mediastinal lymphomas

BACKGROUND

Accurately distinguishing between invasive thymic epithelial tumors (TETs) and anterior mediastinal lymphoma before surgery is crucial for subsequent treatment choices. But currently, the diagnosis of invasive TET is sometimes difficult to distinguish from anterior mediastinal lymphoma.

OBJECTIVE

To assess the application of fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computer tomography (PET/CT) in the differential diagnosis of TETs and anterior mediastinal lymphomas.

METHODS

18F-FDG PET/CT images of 133 invasive TETs and anterior mediastinal lymphomas patients were retrospectively analyzed. In particular, the tumor's longest diameter and maximum standardized uptake value (SUVmax) were evaluated. The SUVmax and longest diameter values of the two groups were analyzed by using the receiver operating characteristic (ROC) curve to determine the optimal threshold and diagnostic efficiency.

RESULTS

Age, myasthenia gravis, SUVmax and tumor longest diameter differed significantly between invasive TETs and anterior mediastinal lymphomas patients. The tumor location, calcification, relationship with adjacent vessels and distant metastasis differed significantly between the groups. The ROC analysis showed an AUC for SUVmax and tumor longest diameter of 0.841 and 0.737. Respectively, the cutoff values with the best diagnostic performance were 9.65 (sensitivity: 77.78%, specificity: 81.97%) and 6.65 (sensitivity: 80.56%, specificity: 62.30%) for SUVmax and tumor longest diameter. The diagnostic model of SUVmax, calcification, relationship with surrounding blood vessels, lymph node metastasis and lung metastasis in the highest AUC of 0.935 (sensitivity: 90.16%, specificity: 88.89%). In addition, we incorporated splenic involvement and metastatic sub-diaphragmatic lymph node into Model 2 as a new predictive model 3 for differential diagnosis and found a significant improvement in the diagnostic performance of Model 3.

CONCLUSION

The diagnostic model composed of 18F-FDG PET parameters is improving the differential diagnosis of invasive TETs and anterior mediastinal lymphomas.

[18F]fluorodeoxyglucose positron emission tomography/computed tomography characteristics of primary mediastinal germ cell tumors

Primary mediastinal germ cell tumor (MGCT) is an uncommon tumor. Although it has histology similar to that of gonadal germ cell tumor (GCT), the prognosis for MGCT is generally worse than that for gonadal GCT. We performed visual assessment and quantitative analysis of [18F]fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) for MGCTs. A total of 35 MGCT patients (age = 33.1 ± 16.8 years, F:M = 16:19) who underwent preoperative PET/CT were retrospectively reviewed. The pathologic diagnosis of MGCTs identified 24 mature teratomas, 4 seminomas, 5 yolk sac tumors, and 2 mixed germ cell tumors. Visual assessment was performed by categorizing the uptake intensity, distribution, and contour of primary MGCTs. Quantitative parameters including the maximum standardized uptake value (SUVmax), tumor-to-background ratio (TBR), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and maximum diameter were compared between benign and malignant MGCTs. On visual assessment, the uptake intensity was the only significant parameter for differentiating between benign and malignant MGCTs (p = 0.040). In quantitative analysis, the SUVmax (p < 0.001), TBR (p < 0.001), MTV (p = 0.033), and TLG (p < 0.001) showed significantly higher values for malignant MGCTs compared with benign MGCTs. In receiver operating characteristic (ROC) curve analysis of these quantitative parameters, the SUVmax had the highest area under the curve (AUC) (AUC = 0.947, p < 0.001). Furthermore, the SUVmax could differentiate between seminomas and nonseminomatous germ cell tumors (p = 0.042) and reflect serum alpha fetoprotein (AFP) levels (p = 0.012). The visual uptake intensity and SUVmax on [18F]FDG PET/CT showed discriminative ability for benign and malignant MGCTs. Moreover, the SUVmax may associate with AFP levels.

[Lesions of the visceral mediastinum]

BACKGROUND

The visceral or middle mediastinum contains nonvascular (trachea, carina, esophagus, and lymph nodes) and vascular structures (heart, ascending aorta, aortic arch, descending aorta, superior vena cava, intrapericardial pulmonary arteries, thoracic duct).

OBJECTIVES

The various pathologies of the visceral mediastinum and imaging features are presented.

MATERIALS AND METHODS

Plain film radiography shows the gross anatomy and allows visualization of larger pathologies. However, for detailed anatomic and structural classification more sophisticated imaging techniques are required. Especially computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) are well suited for structural and functional assessment of mediastinal lesions.

CONCLUSION

This article summarizes the major pathologies of the visceral mediastinum.

The role of minimally invasive surgery in the management of giant mediastinal tumors: a narrative review

BACKGROUND AND OBJECTIVE

Beyond diagnosis, minimally invasive surgery has traditionally not been considered suitable for large tumors, those invading vital structures or high-risk patients. However, with the improvement of multimodality treatments able to reduce tumor size preoperatively, patient evaluation and selection, perioperative care (including both surgical and anesthesiological techniques) and postoperative management, the indications of minimally invasive surgery, even in giant mediastinal tumors, have increased and will continue to broaden in future years. This review aims to summarize the existing literature regarding the role of minimally invasive surgery in the management of giant mediastinal tumors. We have focused in the role minimally invasive surgery has in diagnosis and treatment of these tumors and we have tried to provide an updated perspective to identify future applications and work-directions.

METHODS

Data regarding minimally invasive surgery in giant mediastinal tumors are limited, including a proper definition of them. We performed a PubMed search of English and Spanish written studies until August 2021.

KEY CONTENT AND FINDINGS

There is limited data related to minimally invasive surgery in giant mediastinal tumors and much of the literature review we have performed has yielded isolated case reports, case series with a low number of cases or editorials. Although the role of minimally invasive surgery is well consolidated as a diagnostic approach, adequate patient selection, hospital volume and experience, multidisciplinary discussion of candidates, patient safety and adequate oncological resection remain the most important aspects to be taken into account when considering a minimally invasive approach for a giant mediastinal tumor.

CONCLUSIONS

With careful and multidisciplinary perioperative planning, minimally invasive surgery has shown to be safe and to provide at least similar outcomes when compared to open approaches in well selected cases. Although data is still limited, improved surgical techniques and available technology will pave the way to increased indications of minimally invasive surgery in giant mediastinal tumors.

Differentiating thymoma, thymic carcinoma and lymphoma based on collagen fibre patterns with T2- and diffusion-weighted magnetic resonance imaging

OBJECTIVES

The amount and distribution of intratumoural collagen fibre vary among different thymic tumours, which can be clearly detected with T2- and diffusion-weighted MR images. To explore the incidences of collagen fibre patterns (CFPs) among thymomas, thymic carcinomas and lymphomas on imaging, and to evaluate the efficacy and reproducibility of CFPs in differential diagnosis of thymic tumours.

MATERIALS AND METHODS

Three hundred and ninety-eight patients with pathologically diagnosed thymoma, thymic carcinoma and lymphoma who underwent T2- and diffusion-weighted MR imaging were retrospectively enrolled. CFPs were classified into four categories: septum sign, patchy pattern, mixed pattern and no septum sign. The incidences of CFPs were compared among different thymic tumours, and the efficacy and reproducibility in differentiating the defined tumour types were analysed.

RESULTS

There were significant differences in CFPs among thymomas, thymic squamous cell carcinomas (TSCCs), other thymic carcinomas and neuroendocrine tumours (OTC&NTs) and thymic lymphomas. Septum signs were found in 209 (86%) thymomas, which differed between thymomas and any other thymic neoplasms (all p < 0.005). The patchy, mixed patterns and no septum sign were mainly seen in TSCCs (80.3%), OTC&NTs (78.9%) and thymic lymphomas (56.9%), respectively. The consistency of different CFP evaluation between two readers was either good or excellent. CFPs achieved high efficacy in identifying the thymic tumours.

CONCLUSION

The CFPs based on T2- and diffusion-weighted MR imaging were of great value in the differential diagnosis of thymic tumours.

KEY POINTS

• Significant differences are found in intratumoural collagen fibre patterns among thymomas, thymic squamous cell carcinomas, other thymic carcinomas and neuroendocrine tumours and thymic lymphomas. • The septum sign, patchy pattern, mixed pattern and no septum sign are mainly seen in thymomas (86%), thymic squamous cell carcinomas (80.3%), other thymic carcinomas and neuroendocrine tumours (79%) and thymic lymphomas (57%), respectively. • The collagen fibre patterns have high efficacy and reproducibility in differentiating thymomas, thymic squamous cell carcinomas and thymic lymphomas.

Contrast-Enhanced Ultrasonography versus Contrast-Enhanced Magnetic Resonance Imaging in the Diagnosis of Mediastinal Tumors

The aim of the study was to evaluate and compare contrast-enhanced ultrasound (CEUS) and contrast-enhanced magnetic resonance imaging (CE-MRI) with respect to their value in the differential diagnosis between benign and malignant mediastinal tumors. Forty-two patients with mediastinal tumor underwent CEUS and CE-MRI respectively. The sensitivity, specificity, diagnostic coincidence rate, positive predictive value (PPV) and negative predictive value of the two methods were compared. The value of different enhancement patterns in the differential diagnosis of benign and malignant mediastinal tumors was analyzed. SonoLiver software was used to obtain the dynamic vascular pattern curve (DVPC) of the lesions, and parameters such as arrival time (AT), rise time (RT), time to peak (TTP), maximum intensity/peak intensity (IMAX) and quality of fit (QOF) were extracted from time-intensity curves for quantitative analysis. We found that (i) the specificity of CEUS was higher than that of CE-MRI, and the PPV and diagnostic coincidence rate of CEUS were equal to those of CE-MRI; (ii) the enhancement patterns and DVPC of CEUS differed between the benign and malignant groups, while there was no difference in CE-MRI enhancement intensity; and (iii) AT, RT and TTP in the malignant groups were significantly shorter, while IMAX was significantly higher. In conclusion, the application of quantitative parameters and DVPC of CEUS is worth popularizing. CEUS can be used as an effective alternative and complementary examination for patients who cannot undergo CE-MRI.

[Imaging of Mediastinal Tumors]

In computed tomography, the mediastinum is split into ventral prevascular, middle visceral and dorsal paravertebral compartments. Each compartment contains specific tumours which will be presented and discussed briefly. The focus is on image-based analysis of morphological signs to differentiate between entities using X-rays, ultrasound, CT and MRI. It is however difficult to differentiate between various types of lesions based on morphology and to estimate the grade of malignancy. For this reason, functional imaging techniques like PET and MRI are essential tools for detailed and non-invasive work-up. If a histological tissue examination is required, these tissue samples can be acquired using CT guided biopsies with high diagnostic yield and low complication rates.

Primary Mediastinal HER2-positive Apocrine Carcinoma in Mature Teratoma Treated With Anti-HER2 Therapy and Chemoradiation

BACKGROUND

There are no established guidelines for the management of apocrine carcinomas of the breast; they are treated as a non-specific type of breast cancer.

CASE REPORT

We report on the case of a 40-year-old man who developed primary mediastinal apocrine carcinoma overexpressing human epidermal growth factor-2 (HER2). The patient initially underwent complete resection of a mediastinal mature teratoma with a focal apocrine carcinoma component. Two years after surgery, relapse was detected in multiple mediastinal lymph nodes. He received induction chemotherapy including docetaxel, trastuzumab, and pertuzumab; consolidative concurrent chemoradiation was added after six cycles. A complete response was confirmed using computed tomography following this multimodal therapy. After chemoradiation, adjuvant trastuzumab and pertuzumab were administered for 1 year and the patient has since had no evidence of progressive disease.

CONCLUSION

A multi-modal regimen that includes an anti-HER2 agent appears to be a promising treatment for patients with HER2-positive extramammary apocrine carcinoma.

A Whole-Tumor Histogram Analysis of Apparent Diffusion Coefficient Maps for Differentiating Thymic Carcinoma from Lymphoma

Objective

To assess the performance of a whole-tumor histogram analysis of apparent diffusion coefficient (ADC) maps in differentiating thymic carcinoma from lymphoma, and compare it with that of a commonly used hot-spot region-of-interest (ROI)-based ADC measurement.

Materials and Methods

Diffusion weighted imaging data of 15 patients with thymic carcinoma and 13 patients with lymphoma were retrospectively collected and processed with a mono-exponential model. ADC measurements were performed by using a histogram-based and hot-spot-ROI-based approach. In the histogram-based approach, the following parameters were generated: mean ADC (ADC_mean), median ADC (ADC_median), 10th and 90th percentile of ADC (ADC₁₀ and ADC₉₀), kurtosis, and skewness. The difference in ADCs between thymic carcinoma and lymphoma was compared using a t test. Receiver operating characteristic analyses were conducted to determine and compare the differentiating performance of ADCs.

Results

Lymphoma demonstrated significantly lower ADC_mean, ADC_median, ADC₁₀, ADC₉₀, and hot-spot-ROI-based mean ADC than those found in thymic carcinoma (all p values < 0.05). There were no differences found in the kurtosis (p = 0.412) and skewness (p = 0.273). The ADC₁₀ demonstrated optimal differentiating performance (cut-off value, 0.403 × 10^-3 mm²/s; area under the receiver operating characteristic curve [AUC], 0.977; sensitivity, 92.3%; specificity, 93.3%), followed by the ADC_mean, ADC_median, ADC₉₀, and hot-spot-ROI-based mean ADC. The AUC of ADC₁₀ was significantly higher than that of the hot spot ROI based ADC (0.977 vs. 0.797, p = 0.036).

Conclusion

Compared with the commonly used hot spot ROI based ADC measurement, a histogram analysis of ADC maps can improve the differentiating performance between thymic carcinoma and lymphoma.

Assessment of paraspinal neurogenic tumors with diffusion-weighted MR imaging

PURPOSE

To assess paraspinal neurogenic tumors with diffusion-weighted MR imaging.

METHODS

Retrospective analysis was done upon 34 patients with paraspinal neurogenic tumors that underwent diffusion-weighted MR imaging. The ADC values of the mediastinal neurogenic tumors were calculated and correlated with biopsy results.

RESULTS

The ADC of benign paraspinal neurogenic tumors (1.5 ± 0.28 × 10^-3 mm²/s) was significantly higher (P = 0.001) than that of malignant peripheral nerve sheath tumors (0.995 ± 0.198 × 10^-3 mm²/s). Selection of 1.15 × 10^-3 mm²/s as a cut-off point for differentiating malignant from benign neurogenic tumors revealed an area under the curve of 0.885, an accuracy of 91.1%, a sensitivity of 90.9%, and specificity of 91.3%. There was significant difference (P = 0.04) in the ADC of schwannomas (1.55 ± 0.29 × 10^-3 mm²/s) from neurofibromas (1.33 ± 0.08 × 10^-3 mm²/s). The cut-off ADC value of 1.44 × 10^-3 mm²/s was used to differentiate schwannomas and neurofibromas with an area under the curve of 0.86, an accuracy of 82.6%, a sensitivity of 100%, and a specificity of 76.5%.

CONCLUSION

Diffusion-weighted MR imaging is imaging parameter that can be used for differentiation of benign from malignant paraspinal neurogenic tumors.