Thymoma is the most common neoplasm of the anterior mediastinum and accounts for one quarter of all mediastinal tumours and half of all anterior mediastinal masses. Pericardial effusion may be present in approximately 20% of cases. This report presents a patient with a previously diagnosed thymoma without surgical indication and with poor response to chemotherapy and radiotherapy who had a pericardial effusion that likely resulted from the malignancy dissemination to pericardium.
Although its incidence is rare, thymoma is the most common neoplasm of the anterior mediastinum, accounting to 20% - 25% of mediastinal tumours and approximately half of the tumours of the anterior mediastinum, of which 20% - 30% are invasive. Most patients are between 40 and 60 years of age, and there is a slight female predominance. Most of thymomas are solid tumours, but more than one third may have necrotic, hemorrhagic or cystic components. Approximately one third of thymomas invade the capsule, extending up to adjacent structures. Transdiaphragmatic extension to the abdomen and pleural and pericardial metastases can occur, however haematogenous and lymphatic dissemination is rare [
Since the majority of patients do not present nodal disease or metastases, the tumour, node, metastasis staging system is not particularly useful for thymomas. Therefore, the extent of the primary tumour is particularly relevant. The Masaoka staging system is a widely applied tool in studies of thymoma, given the tumour rarity and histopathologic heterogeneity [
One third to one half of patients with a thymoma is asymptomatic, and 33% of patients present with local symptoms related to the involvement of surrounding structures. Although only one-third of patients with localized disease is symptomatic, most patients with disseminated disease have significant complaints, such as chest pain, chest discomfort, dyspnea, and superior vena cava syndrome [
The authors report a case of previously diagnosed thymoma associated with pericardial effusion, in a patient with myasthenia gravis, poor response to chemotherapy and radiotherapy and subsequently pericardial disseminated neoplasm.
A 65-year-old caucasian woman, independent in her daily life activities, was admitted in our Internal Medicine Ward with hypercapnic respiratory failure requiring non-invasive ventilation. This patient presented a past medical history of type B2 cortical thymoma with pleural and pulmonary dissemination diagnosed in 2007, not amenable to complete resection, followed by Thoracic Surgery. The chemotherapy performed (8 cycles) had low chemosensitivity and provoked severe toxicity. A diagnosis of parathymic syndrome with myasthenia gravis was confirmed in 2012 and mestinon® therapy was initiated. The latest follow-up computed tomography scans (ten months before the current hospital admission) showed an increased cardiothoracic ratio with scarce pericardial effusion. Physical examination revealed dyspnoea at rest, blood pressure 105/62 mmHg, tachycardia (112 beats/min), with soft heart sounds, but no murmurs or friction rub were auscultated. The neck veins were not distended. Laboratory findings identified increased inflammatory parameters (leukocytosis 12760 × 106 L, neu-
Stage | Diagnostic criteria |
---|---|
I | Macro- and microscopically completely encapsulated tumour |
II-A | Microscopic transcapsular invasion |
II-B | Macroscopic invasion into surrounding fatty tissue or grossly adherent |
III | Macroscopic invasion into neighboring organs |
III-A | Without invasion of great vessels |
III-B | With invasion of great vessels |
IV-A | Pleural or pericardial dissemination |
IV-B | Lymphogenous or hematogenous metastases |
Adapted from [
trophilia 80% and elevated CRP 11.5 mg/dL). Electrocardiogram presented with sinus tachycardia and low voltage. Chest radiograph revealed an increased cardiothoracic ratio, mediastinal widening and opacity in the middle lobe of the right lung (
A transthoracic echocardiogram was performed which demonstrated a circumferential pericardial effusion with a swimming heart, without diastolic collapse of the right cavities.
Thoracic computed tomography (CT) scans showed a heterogeneous anterior mediastinal lesion with areas of central necrosis, necrotic nodular lesion of the pleura in relation to the right costophrenic angle and significant pericardial effusion. It also presented with extensive areas of lung consolidation with air bronchogram compatible with bilateral basal pneumonia and associated parapneumonic left pleural effusion (
The case was discussed with Thoracic Surgery and Cardiology that excluded the need for pericardial drainage. It was admitted this clinical presentation in the context of a disseminated thymoma to pericardium. The conservative treatment included diuretic therapy with spironolactone and furosemide. Echocardiography was repeated three times, always without signs of cardiac tamponade. The patient fulfilled non-invasive ventilation with gradual weaning and no indication for long-term oxygen therapy. She was discharged clinically improved. Thoracic computed tomography was repeated within 6 months, revealing an increase in the anterior mediastinum mass and metastasis dimensions. New chemotherapy scheme was proposed, however it was discontinued due to patient’s intolerance. Currently, the patient has supportive care and monitoring in Thoracic Surgery and Internal Medicine appointments.
Thymomas are typically indolent, slow-growing tumours with local dissemination [
According to the Masaoka Clinical Staging, the grade of invasion of our patient’s thymoma can be stratified in stage IVA due to its pleural and pericardial dissemination. It was not considered amenable to complete resection so the diagnosis was established prior to therapy using biopsy. Noteworthy, on average, only 25% of patients with stage IV thymomas are submitted to complete resection. For initially Masaoka stage IVA unresectable disease, it is recommended treatment with neoadjuvant chemotherapy [
mited [
Finally, the natural history and prognosis without treatment of thymomas is not yet fully understood. In general, 50% of the deaths are attributed to the thymoma or to the treatment. Approximately 75% of deaths in patients with stage IV disease are due to thymoma [
The relative infrequency of thymoma makes this malignancy often poorly understood. Although thymomas are usually slow-growing tumours, the clinical staging is the mainstay for prognostication. Compared to the histological categorization, the Masaoka staging system is a more useful tool when determining the optimal therapy for a thymoma. This case report highlights the need to continue to debate controversial topics such as the choice, sequencing and timing of the neoadjuvant therapies and the appropriateness of surgery in disseminated thymomas.