CARCINOID-TUMORS OF THE THYMUS

Background - Carcinoid tumours of the thymus are rare. The clinical manifestations, radiographic findings, and cytological features of eight histopathologically verified thymic carcinoid tumours have been assessed. Methods - One hundred and sixty two patients of mean age 52 (range 31-68) years with malignant mediastinal tumours were reviewed retrospectively and eight cases of thymic carcinoid were identified. Four of the eight patients were diagnosed by percutaneous ultrasound guided fine needle aspiration biopsy via a parasternal approach. Results - Two patients had Cushing's syndrome at presentation and four had symptoms and signs secondary to mediastinal compression. Two were asymptomatic. Local extension of the tumour to pleura, pericardium, great vessels, phrenic nerve or regional lymph nodes, or both, were found in seven patients. Only one had the tumour confined to the thymus at diagnosis. Distant metastases were found in two patients, one to both lungs and the other in the iliac bone. Local recurrence or distant metastases developed 15-60 months after surgery in four of the five patients who underwent radical resection of the thymic tumour. Three patients died at 17 months, 34 months, and 10 years after diagnosis. The other five patients are alive at 9-51 months. Conclusion - Thymic carcinoid is a slow growing tumour with a poor prognosis because of its tendency to local and distant spread. Cytological examination of samples obtained by ultrasound guided fine needle aspiration may provide a useful method for diagnosis in selected patients.