Treatment of thymoma with low-dose glucocorticoids before surgery for significant tumor shrinkage: A case report

Abstract

BACKGROUND

Thymic epithelial neoplasms are rare malignant neoplasms originating in the thymus gland. There have been case reports of patients with advanced thymomas treated with a methylprednisolone pulse or with glucocorticoid (GCs) shock before surgery, followed by surgical treatment, all of whom achieved good results. The effect of GCs on thymomas is related mainly to the action on GC receptors in thymic lymphocytes and epithelial cells. GC receptor expression has been associated with a better prognosis in patients with thymomas, including those with surgically removed thymomas.

CASE SUMMARY

We report a case of a patient with thymoma who had a significant response to preoperative low-dose GC therapy. A mediastinal tumor was detected in the patient via computerized tomography upon admission. The tumor was initially suspected to be a thymic tumor, but lymphoma could not be ruled out. The tumor shrank significantly after low-dose (5 mg/day) GC therapy. Thoracoscopic thymoma resection was performed after puncture pathology was confirmed. The patient recovered well after the operation and is currently performing well with no recurrence of the tumor.

CONCLUSION

This case highlights that low-dose GCs are effective in the treatment of thymomas, and we believe that GCs should be applied more frequently and studied more thoroughly in the treatment of thymomas.

Key Words: Thymoma; Glucocorticoid; Diagnosis; Shrinkage; Treatment; Case report

Core Tip: This study reports a case of a thymoma patient whose tumor significantly shrank following preoperative treatment with low-dose glucocorticoids (GCs). The low-dose GC therapy demonstrated promising efficacy, promoting tumor reduction, minimizing intraoperative adhesions, and facilitating smooth postoperative recovery without recurrence. This study highlights the potential of GCs in the management of thymoma and calls for further investigation into their application in therapeutic strategies.

INTRODUCTION

Thymic epithelial tumors are rare malignant tumors originating in the thymus[1]. The overall incidence of thymomas in the United States is 0.13 per 100000 person-years[2]. Histologically, thymic epithelial tumors are classified into various subtypes, including type A, AB, B1, B2, B3, and C thymic carcinomas[3]. Thymomas can present with various manifestations, such as myasthenia gravis and local symptoms, or are asymptomatic and detected as mediastinal masses on chest X-ray[4-6]. For resectable thymomas, especially for invasive thymomas, postoperative radiotherapy is recommended[7]. Complete thymectomy is typically performed in specific cases[8]. Platinum chemotherapy is still the standard treatment for advanced thymomas that cannot be completely resected by surgery[9]. Initiation of chemotherapy to optimize surgical excision and consolidation to control residual lesions may improve the prognosis of patients with advanced thymomas[10-12].

At present, there are case reports that advanced thymomas can be controlled by methylprednisolone pulse therapy with good efficacy[13]. Moreover, preoperative glucocorticoid (GC) impact therapy has a significant effect on stage B1 thymoma, and the preoperative tumor burden in patients is significantly reduced[14]. However, there are currently almost no clinical studies on the application of low-dose GCs in the treatment of thymoma. We hope that this report on the preoperative use of low-dose GCs in the treatment of a thymoma will provide new ideas for the application of GCs in the treatment of thymomas.

CASE PRESENTATION

Chief complaints

A 44-year-old young patient with chest tightness examined chest computed tomography (CT) and found anterior mediastinal space.

History of present illness

In August 2023, a 44-year-old patient with chest tightness was examined via chest CT and an anterior mediastinal space tumor was detected. The patient was admitted with a temperature of 38.2 °C. The patient was healthy in the past and had no bad habits, such as smoking or drinking. The patient had occasional chest tightness and pain but no related clinical symptoms of myasthenia gravis and sought treatment at our hospital because of the aggravation of chest tightness symptoms.

History of past illness

The patient had no specific past medical history.

Personal and family history

The patient had no personal and family history.

Physical examination

He had a physical examination but found no obvious positive signs.

Laboratory examinations

Routine blood tests revealed that the white blood cell count was 15.97 × 10⁹/L, the lymphocyte count was 3.11 × 10⁹/L, and the monocyte count was 2.25 × 10⁹/L. Other blood tests showed no obvious abnormality.

Imaging examinations

Chest CT revealed a soft-tissue shadow that was visible on the right side of the anterior mediastinum.

FINAL DIAGNOSIS

The patient was eventually diagnosed with thymoma.

TREATMENT

The cooling effect of daily intravenous injection of 5 mg of dexamethasone sodium phosphate was significant, as shown in Figure 1, and chest CT reexamination revealed a significant reduction in the thymic mass.

Figure 1 Computed tomography examination of the patient. A: On August 23, 2023, enhanced chest computed tomography (CT) revealed a soft-tissue shadow that was visible on the right side of the anterior mediastinum, with a size of approximately 78 mm × 53 mm. After enhancement, the mass was uneven and mildly enhanced, the surrounding fat space was blurred, and the superior vena cava and the right atrium were compressed; B: On August 28, 2023, chest CT revealed a soft-tissue shadow that was visible on the right side of the anterior mediastinum; the size of the mass was approximately 64 mm × 55 mm, the surrounding fat space was blurred, and the superior vena cava and the right atrium were compressed; C: On September 11, 2023, chest CT revealed a soft-tissue shadow that was visible on the right side of the anterior mediastinum; the size of the mass was approximately 39 mm × 54 mm, the surrounding fat space was blurred, and the sizes and shapes of the large blood vessels of the heart were normal.

OUTCOME AND FOLLOW-UP

When professor Huang’s expert team discussed the condition, they consulted the relevant literature and found that in other countries, the preoperative application of GCs could effectively reduce the thymus tumor volume and improve the surgical effect; thus, dexamethasone sodium phosphate was used for 2 weeks. Considering that the patient's disease could not exclude the possibility of lymphoma, B-ultrasound-guided transesophageal mediastinal mass puncture was performed after admission. Thymoma was pathologically confirmed (Figure 2), and surgery was scheduled. Extubation was performed 3 days after surgery, and routine pathology revealed a type B2 anterior mediastinal thymoma (Figure 3). To date, the patient has recovered well, and the tumor has not returned. The entire process of patient treatment, from admission to discharge, is shown in Figure 4.

Figure 2 Preoperative pathology. Preoperative pathology revealed a small amount of lymphoid tissue and epithelioid cells with necrosis. When combined with immunohistochemical results, which were consistent with thymoma, and considering that there was little tissue, it was recommended that specimens be further classified after surgery. The immunohistochemistry results were as follows: TdT (partial +), CD5 (partial +), CD20 (small +), CD3 (partial +), CK (AE1/AE3) (+), CK19 (+), p63 (+), Ki-67 (20% +), CDla (partial +), CD117 (individual +), CK (+), and p53 (minor +). HE: Hematoxylin and eosin.

Figure 3 Postoperative pathology. Postoperative pathology revealed anterior mediastinal thymoma (type B2), cyst formation in some areas, fibrosis and large necrosis, and infiltration of the capsule. Immunohistochemistry revealed the following: CK (AE1/AE3) (+), CK19 (+), CK5/6 (+), p63 (+), Ki-67 (+), TdT (-), CD5 (-), CD20 (-), CD3 (-), CDla (-), and CD117 (-). HE: Hematoxylin and eosin.

Figure 4 Patient treatment flowchart. CT: Computed tomography.

DISCUSSION

In this case, the patient experienced excellent GC therapy outcomes before surgery. The mass was significantly reduced, there was less intraoperative adhesion, and the separation of the pericardium and thymus tissue was smooth. These findings suggest that the GC promoted a significant shrinkage of the thymoma in this patient. Indeed, there have been previous reports of thymoma regression after GC therapy[14,15], which is consistent with the findings reported in this case. These findings suggest that GCs can promote the obvious shrinkage of thymomas in patients. After the patient was admitted to the hospital, we consulted the relevant literature and found many case reports of GC shock therapy for thymomas. Some scholars have conducted prospective studies with the administration of GC shock therapy for 2 weeks before surgery and reported that the effects on B1, B2 and B3 thymomas were significant, and most patients experienced partial remission before surgery and no recurrence after surgery[14]. In Nakamura et al’s report[13], a patient with a metastatic thymoma that was well controlled by methylprednisolone pulse therapy plus immunosuppressants was described. In patients with metastatic thymomas, especially in those with myasthenia gravis, the use of GCs has been affirmed by many studies for their positive effects[16]. However, no studies have discussed in detail the influence of the duration of GC use and its benefits before and after surgery. In addition, these studies were based on high-dose corticosteroid shock therapy, while our patient achieved significant tumor shrinkage with 5 mg of a corticosteroid per day. In previous studies, only one patient with thymoma-induced pleural effusion was reported to have been treated with a low dose of GCs, but the effect was significant[17]. These findings suggest that it may be possible to achieve good results with small amounts of hormones in patients with preoperative thymoma.

GCs, a class of steroid hormones, are important regulatory molecules that control inflammation, cell growth and differentiation through the activity of specific intracellular GC receptors (GRs)[18,19]. In the normal thymus, GRs are expressed not only in immature thymus cells but also in epithelial cells, and high GR expression can also be detected in thymoma cells. Therefore, the effect of GCs on thymomas is related mainly to the effects of GRs on thymoma cells and epithelial cells. A study by Mimae et al[20] revealed high GR expression rates in thymomas, and multivariate analysis revealed that GR expression was associated with a better prognosis in patients with thymomas, including those with surgically removed thymomas.

In our case, there were positive pathological changes before and after hormone therapy, which provided effective case support for our study of the effects of GCs on thymoma. We report the case of a patient who was hospitalized for a large thymoma, with a pre-steroid biopsy showing immature TdT (+) and CD5 (+), CD20 (+), and CD3 (+) T lymphocytes, and post-steroid resection pathology revealing TdT (-), CD5 (-), CD20 (-), and CD3 (-) cells. These findings suggest that GCs cause the loss of immature lymphocytes in thymus tumors. This finding is consistent with the findings of Tateyama et al[21], who reported that corticosteroids might cause degenerative changes in epithelial cells and immature T lymphocytes. Kobayashi et al[14] noted that the reduction in the size of thymomas rich in these immature lymphocytes with steroid treatment could be explained by the reduction in the number of most lymphocytes. This could explain why the tumors shrunk so much after GC therapy. Kobayashi et al[14] also reported that preoperative GC pulse treatment resulted in a much greater reduction in B1 thymomas than in other types of thymomas because B1 thymomas have large numbers of immature double-positive [CD4 (+) and CD8 (+)] lymphocytes, which are very sensitive to GC-induced apoptosis.

Notably, studies have shown that GCs can also directly inhibit the proliferation of tumor cells. This may be because GCs affect tumor cells by inducing G1 phase cell cycle arrest in human thymus tumor epithelial cells[22]. In this study, there were a small number of cases in which tumors still grew slowly after steroid therapy, which the authors believe may be related to the short duration of steroid hormone use and the type of pathology. We hope that further studies will confirm the appropriate duration of preoperative steroid use and analyze its benefits depending on the pathological types in patients. In summary, we believe that GCs can effectively control the progression of thymomas. We also believe that for thymoma patients with large tumor volumes or chest tightness, the use of low-dose GC therapy can be considered before surgical treatment, which may be conducive to curing patients. We also look forward to more similar cases or studies to provide clinical evidence for preoperative GC therapy. At present, there are no authoritative guidelines for the preoperative use of hormone therapy for thymomas. This case provides a better idea for the treatment of thymoma and has certain reference value for clinicians. The explanation of the mechanism of action of hormones in the treatment of thymoma could be improved in the future, and the application of hormone therapy in the treatment of thymoma could be supported by a systematic theory. In the future, we may conduct more in-depth research on the timing of hormone therapy before thymoma surgery and whether to use hormone therapy after surgery so that patients with thymomas can receive better treatment.

CONCLUSION

This report reports a case of thymoma sensitive to low dose GCs. It highlights the need to consider preoperative trials of low-dose GC therapy in patients with significant discomfort or large, suspected thymomas.