Background - Carcinoid tumours of the thymus are rare. The clinical ma
nifestations, radiographic findings, and cytological features of eight
histopathologically verified thymic carcinoid tumours have been asses
sed. Methods - One hundred and sixty two patients of mean age 52 (rang
e 31-68) years with malignant mediastinal tumours were reviewed retros
pectively and eight cases of thymic carcinoid were identified. Four of
the eight patients were diagnosed by percutaneous ultrasound guided f
ine 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 p
atients. Only one had the tumour confined to the thymus at diagnosis.
Distant metastases were found in two patients, one to both lungs and t
he other in the iliac bone. Local recurrence or distant metastases dev
eloped 15-60 months after surgery in four of the five patients who und
erwent radical resection of the thymic tumour. Three patients died at
17 months, 34 months, and 10 years after diagnosis. The other five pat
ients are alive at 9-51 months. Conclusion - Thymic carcinoid is a slo
w growing tumour with a poor prognosis because of its tendency to loca
l and distant spread. Cytological examination of samples obtained by u
ltrasound guided fine needle aspiration may provide a useful method fo
r diagnosis in selected patients.