Pathological Features and Prognosis of Thymoma With or Without Myasthenia Gravis

Thymoma With Myasthenia Gravis: A Study of Two Cases

Thymoma is a rare, primary neoplasm of the thymus gland, commonly presenting in adults and associated with autoimmune diseases, most commonly myasthenia gravis (MG). Despite its generally indolent behavior, the variability in clinical presentation and potential for malignancy necessitates detailed evaluation and management. In this report, we present two cases: a 41-year-old male and a 39-year-old female, both of whom presented with a mediastinal mass with symptoms of myasthenia. Further investigation, including imaging and histopathological examination, confirmed the diagnosis of a type B2 thymoma and type B1 thymoma for the male and female patients, respectively. The patients underwent successful complete surgical resection of the masses, with the postoperative recovery being uneventful. They were monitored for signs of disease recurrence and associated autoimmune conditions during follow-up visits. This report underscores the importance of early detection and thorough clinical evaluation of thymoma, particularly in patients with associated paraneoplastic syndromes. Complete surgical resection remains the cornerstone of treatment, with adjuvant therapy tailored based on individual risk factors. Ongoing surveillance is crucial for identifying potential recurrences and associated conditions.

Clinical features of thymoma with and without myasthenia gravis

Objective

To explore the clinical features of thymoma with and without myasthenia gravis (MG).

Methods

This was a retrospective study. Two hundred and thirty-three patients with mediastinal masses who were initially diagnosed in People's Hospital of Shijiazhuang, China, between January 2014 and June 2022 and had complete clinical data and underwent surgical treatment at People's Hospital of Shijiazhuang were retrospectively analyzed.

Result

The age of patients with thymoma alone was significantly older than that of thymoma patients complicated with MG. The number of female patients was slightly more than males for both groups. Proportions of type A, AB, B1, B2, and B3 thymomas in Group-A were 0.77, 11.54, 11.51, 33.85, and 31.54%, respectively, and the proportions in Group-B were 9.68, 22.58, 12.90, 32.26, and 22.58%. The size of tumors in patients with thymoma alone was larger than that of patients with thymoma complicated with MG. The proportion of patients with tumor size of more than 10 cm in the thymoma alone group was significantly higher than that in the MG group. There were no relapses in patients with type A disease and relapses were noted in a few patients with type B1, B2 and B3 diseases. The same survival rates were reported for the two groups.

Conclusion

MG rarely occurs in type A and type C diseases. The prognosis of thymoma with MG is similar to that of thymoma alone. The main causes of death may be myasthenia crisis in thymoma patients with MG and advanced tumor stage in patients with thymoma alone.

Long-term prognosis in patients with thymoma combined with myasthenia gravis: a propensity score-matching analysis

Introduction

We aimed to assess the impact of myasthenia gravis (MG) on the long-term prognosis in patients with thymoma after surgery and identify related prognostic factors or predictors.

Methods

This retrospective observational study included 509 patients with thymoma (thymoma combined with MG [MG group] and thymoma alone [non-MG group]). Propensity score matching was performed to obtain comparable subsets of 96 patients in each group. A comparative analysis was conducted on various parameters.

Results

Before matching, the 10-year survival and recurrence-free survival rates in both groups were 93.8 and 98.4%, and 85.9 and 93.4%, respectively, with no statistically significant difference observed in the survival curves between the groups (p > 0.05). After propensity score matching, 96 matched pairs of patients from both groups were created. The 10-year survival and recurrence-free survival rates in these matched pairs were 96.9 and 97.7%, and 86.9 and 91.1%, respectively, with no statistical significance in the survival curves between the groups (p > 0.05). Univariate analysis of patients with thymoma postoperatively revealed that the World Health Organization histopathological classification, Masaoka-Koga stage, Tumor Node Metastasis stage, resection status, and postoperative adjuvant therapy were potentially associated with tumor recurrence after thymoma surgery. Multivariate analysis demonstrated that the Masaoka-Koga stage and postoperative adjuvant therapy independently predicted the risk of recurrence in patients with thymoma after surgery.

Conclusion

There was no difference in prognosis in patients with thymoma with or without MG. The Masaoka-Koga stage has emerged as an independent prognostic factor affecting recurrence-free survival in patients with thymoma, while postoperative adjuvant therapy represents a poor prognostic factor.

Unique association of anti-GABAA receptor encephalitis and myasthenia gravis in a patient with type A thymoma

Association between anti-GABAAR encephalitis and myasthenia gravis is extremely rare with few reported cases. Herein, we report a case of a female patient diagnosed with anti-GABAAR encephalitis and thymoma at the first admission. She was administered glucocorticoids for long-term immunotherapy, and thymectomy with biopsy demonstrated a type A thymoma. After 4 months, the symptoms of encephalitis were relieved, but she then developed post-thymectomy myasthenia gravis with anti-AChR and anti-titin dual positivity. Antibodies to connective tissue (anti-ANA, anti-PCNA) and those characteristics of paraneoplastic syndrome (anti-Ma2/Ta) were also positive. She received oral glucocorticoids and tacrolimus as immunosuppressive therapy, and myasthenic symptoms were stable during a 2-year follow-up. Our case revealed that anti-GABAAR encephalitis and myasthenia gravis can appear in patient with type A thymoma at different periods, which alerts physicians to take long-term follow-up for anti-GABAAR encephalitis with thymoma, even after thymectomy. Concurrent positivity for more than one antibody after thymectomy is rarely observed, and their contribution to the clinical course and treatment decision remains to be further investigated.

Perspectives on surgical treatment for thymic epithelial tumors: a narrative review

Background and Objective

Thymic epithelial tumors are relatively rare; thus, mostly retrospective studies and a few prospective randomized controlled trials have been conducted on the treatment and the biomarkers, with no standard therapy established. Indications for extended thymectomy, robot-assisted thoracic surgery, and multidisciplinary treatment are controversial. Here, we considered the prospects of surgical treatment and the possibility of immune checkpoint inhibitor (ICI) treatment for thymic epithelial tumors.

Methods

This is a narrative review; PubMed was searched using a set of keywords related to thymoma and its proposed treatments over the last 5 years.

Key Content and Findings

Thymic epithelial tumors are associated with autoimmune diseases. They are relatively rare, and their pathology remains unclear. Therefore, accumulating more case reports is important. Surgical resection is generally considered for both diagnosis and treatment. If the tumor has a strong tendency to invade surrounding areas, such as thymic carcinoma/thymoma, the diagnosis may be confirmed preoperatively by needle biopsy, and induction chemotherapy may be selected. Surgical resection is the most effective treatment, and complete resection is important. In cases where complete resection is difficult, multidisciplinary treatment is performed. Although there are various obstacles, using ICIs may prove effective for treatment both as preoperative and postoperative chemotherapy in the future, as shown for other cancers. Programmed cell death-ligand 1 (PD-L1) is an immunoinhibitory molecule that suppresses T cells activation, leading to tumor progression. Overexpression of PD-L1 in some cancers is associated with poor clinical outcomes. However, the role of PD-L1 expression as a prognostic factor remains controversial. Therefore, various biomarkers other than PD-L1 have been identified.

Conclusions

We reviewed the latest treatments for thymic epithelial tumors. If new therapeutic agents such as ICIs and molecular-targeted drugs are developed, this review suggests that surgery will become more important not only as therapy but also as part of multidisciplinary treatment that includes tissue collection.

Modified subcostal arch xiphoid thoracoscopic expanded thymectomy for thymic carcinoma: a case report and review of literature

Thymic neoplasms are a relatively uncommon tumor, with the anterior mediastinum being the most common. Median sternotomy is the procedure of choice for the treatment of thymomas. With the advent of thoracoscopy, an increasing number of countries are adopting the right thoracic approach for the treatment of thymomas, but there are still no clear surgical standards or modalities to treat thymic carcinoma. We propose a modified subxiphoid subcostal arch thoracoscopic enlarged thymectomy to treat thymic carcinoma based on various reviews. We have also reviewed the relevant literature on the subject of evidence-based medicine. The evaluation of CD70 in combination with CD5 and CD117 or preferentially expressed antigen in melanoma in combination with CD5 and CD117 may help to diagnose thymic squamous cell carcinoma (TSCC) more accurately. The modified thoracoscopic expanded thymic resection under the costal arch of the xiphoid process is not only suitable for TSCC but also for thymic cyst, thymoma, locally invasive thymoma, and thymic carcinoma.

Characterization of IL-10-producing regulatory B cells in thymoma

BACKGROUND

Regulatory B cells (Bregs) are a subset of B cells that secrete interleukin 10 (IL-10) and play a vital role in suppressing the immune response. The aim of this study was to evaluate the proportion of Bregs in patients with thymoma.

METHODS

The proportions of subgroups of Bregs in 23 patients with thymoma and 15 healthy controls were detected by flow cytometry. The serum IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ, and TNF-α levels of the subjects were measured using a cytometric bead array (CBA).

RESULTS

The proportions of circulating IL-10⁺ B cells, IL-10⁺CD24^hiCD38^hi Bregs, and IL-10⁺CD24^hiCD27⁺ Bregs and the serum IL-10 level were significantly higher in patients with thymoma than in the control group and were negatively correlated with the Karnofsky Performance Scale (KPS) score. The serum levels of cytokines IL-2, IL-6, IFN-γ, and TNF-α were higher and serum IL-17A level was lower in patients with thymoma. Patients with advanced-stage thymoma exhibited significantly higher proportions of IL-10-producing Bregs and a higher serum IL-10 level. After tumour resection, the frequency of circulating IL-10⁺CD24^hiCD38^hi Bregs and the serum IL-10 level were significantly decreased in patients with thymoma. The serum IL-10 levels exhibited the best accuracy in assessing the risk of thymoma occurrence in this study.

CONCLUSIONS

The expression of IL-10 produced by Bregs is increased in patients with thymoma, particularly those with advanced-stage disease, which may suggest that Bregs are involved in the pathogenesis and progression of thymoma.