Introduction: CT- guided core needle biopsy, followed by mediastinoscopy with incisional biopsy is the preferred approach in radiologically suspected thymoma or thymic carcinoma. Endobronchial ultrasound (EBUS) allows for detailed inspection of paratracheal, anterior mediastinal mass. In addition different areas of the mass can be safely biopsied under real time ultrasound guidance to increase the diagnostic yield. Case Report: A 55-years-old male presents to the emergency department with history of progressive shortness of breath over 3-4 months, fatigue and retrosternal chest pain. On examination he was noticed to have mild respiratory distress and temporal wasting. He endorsed loss of appetite and significant weight loss. Initial work up in the emergency department revealed widening of mediastinum. Computed tomography scan of chest confirmed anterior mediastinal mass encasing and compressing the right pulmonary artery, concerning for malignancy. Pulmonary service was consulted as patient refused mediastinoscopy. EBUS bronchoscopy was performed with detailed inspection of anterior mediastinal mass, different areas were biopsied under real time ultrasound guidance. Rapid onsite cytology evaluation confirmed presence of atypical cells. Histochemistry and consensus cytology review established diagnosis of thymic carcinoma. Discussion: Thymoma and thymic carcinoma are epithelial tumors of the thymus. Anterior mediastinal tumor with atypical cells, loss of thymic architecture and absence of mature lymphocytes represents thymic carcinoma. It is rare and account for 0.06% of all thymic neoplasms. In general thymic carcinomas are invasive, with a higher risk of relapse and death. A specific cytologic diagnosis of thymic carcinoma is among the most difficult attempted in fine needle aspiration (FNA) cytopathology. Proper and adequate sampling of FNA is critical in establishing the diagnosis as most biopsies lack tissue architecture. Endobronchial ultrasound allows for detailed inspection of tumor allowing for selection of different areas for biopsy due to biphasic histologic nature of thymoma. Zarowski MF et, al in their study of 22 patients with thymic tumors compared cytologic and surgical diagnosis. They reported 100% sensitivity with stress on co-relation with clinical and radiographic information. Conclusion: In patients with clinical and radiographic suspicion of thymic carcinoma. EBUS with fine needle aspiration biopsy is safe. In addition the diagnostic yield can be increased with a comprehensive biopsy approach, targeting different areas of the mass. It is important for cytopathology to include clinical and radiographic information before diagnosing thymic carcinoma on a FNA biopsy specimen.
Ghori, Uzair and Ali Imran Saeed. "Clinical vignette: Endobronchial ultrasound with fine needle aspiration biopsy of anterior mediastinal mass; a safe and comprehensive biopsy approach in establishing diagnosis of thymic carcinoma." (2014). https://digitalrepository.unm.edu/hostpitalmed_pubs/39