Thymomas, although rare, are common primary tumors in the anterior mediastinum1. It constitutes 0.2 to 1.5% of all malignancies with an annual incidence of 0.15 cases for every 100,000 individuals2. Though they can spread locally, they are less invasive compared to thymic carcinomas. This is rare in children and peaks during the fifth decade of life2. Most patients are asymptomatic; however, others would present with chest pain, dyspnea, and superior vena cava obstruction3. Diagnosis is incidental in most cases and histopathology is the cornerstone of diagnosis3. We therefore present a case of Thymoma in a patient who had the disease yet remained asymptomatic for almost a decade.

Case Presentation. This is a case of a 62-year-old Filipino female who came in due to dyspnea. 8 years prior to admission, during annual physical exam, chest x-ray was done which showed anterior mediastinal mass. CT scan of the chest was requested revealing anterior mediastinal mass, right. With this finding, she was advised to undergo biopsy which revealed presence of atypical cells to consider Thymoma versus Lymphoma. She was advised for repeat biopsy; however, she was unable comply and was lost to follow up.

In the interim, patient noted onset of occasional cough associated with weight loss and worsening dyspnea. She had negative result for sputum gene Xpert, AFP and B-HCG. Repeat CT scan of the chest with contrast revealed pulmonary mass at the right paracardiac region, right pleural effusion and loculated effusion at the right oblique fissure. Hence, ultrasound of the hemithorax was requested and showed loculated pleural fluid in the right hemithorax approximately 534mL. Two-dimensional echocardiogram with doppler studies showed moderate pericardial effusion measuring 1.29 cm without tamponade. Pleural fluid analysis was consistent with a chronic disease process such as malignancy or TB pleurisy.

Patient was referred to general surgery, but the mass was unresectable at this time. Chest tube thoracostomy can’t also be performed, hence ultrasound-guided thoracentesis was attempted in which only 35 mL of serosanguinous pleural fluid was drained. She was then advised to undergo chemotherapy with CAP (Cisplatin, Doxorubucin, and Cyclophospamide) regimen in which she complied. Patient was eventually discharged improved.

Conclusion. The patient remained asymptomatic for nearly a decade, with the tumor identified only through incidental findings. Given the lack of pathognomonic features, this case highlights the need for a high index of suspicion and comprehensive diagnostic evaluation. Additionally, the involvement of a multidisciplinary team was essential in confirming the diagnosis and formulating an effective management plan.

Keywords. thymoma, anterior mediastinal mass, chemoradiation, surgery

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