Is a diagnostic video-assisted thoracoscopic thymectomy an acceptable first-line approach to the suspicious anterior mediastinal mass?

INTRODUCTION: The incidental early-stage thymic mass presents a diagnostic challenge. Video-assisted thoracoscopic (VAT) thymectomy is an attractive but potentially morbid solution. The aim was to show it can be safely applied as a first-line modality in those with undiagnosed thymic enlargement with acceptable long-term results.

METHODS: A total of 45 patients were identified (24 male, median age 52 interquartile range [IQR]: 41-66 years) in a 14-year experience who had CT evidence of an enlarged, possibly malignant thymic mass, but no tissue diagnosis before undertaking VAT thymectomy. The clinical outcomes of both benign and malignant diagnoses were compared.

RESULTS: Myasthenic symptoms were present in 20 patients (44%), whereas 15 (33%) were asymptomatic. Benign lesions were resected in 27 patients (60%): thymic hyperplasia (56%), thymic cyst (33%), lipoma (7%) and xanthogranulomatous inflammation (4%). Of the 18 malignant patients, 82% had thymoma (three had Masaoka Stage I, 11 Stage II and one Stage III), 6% thymic carcinoma, 6% teratoma and 6% seminoma. Seven patients required radiotherapy for R1 resection. There was no difference in median hospital stay in either group: Benign group: 4 versus 5 days (P = 0.07). One patient in both groups required conversion to open. Two patients in the malignant group had significant morbidity (one myocardial infarction and one pulmonary embolism). There were no cases of tumour recurrence or mortality at a median follow-up of 6.6 years (IQR: 4.4-9.5 years).

CONCLUSION: Right-sided diagnostic VAT thymectomy is a safe and effective first-line approach to suspected malignant thymic enlargement. At 5-year follow-up, there were no cases of recurrence in the malignant group.