Peripheral carcinoid tumours of the lung: a clinicopathological study.

Peripheral carcinoid tumours (PCT) of the lung are a distinct entity. These tumours arise from subsegmental or distal bronchioles, are usually well circumscribed and encapsulated, and contain varying amounts of spindle cells. Their histogenesis is from the Kultchitsky or neurosecretory type of cells. Of 52 patients with carcinoid tumours of the lung, 11 (21.1%) had PCT. The mean age was 60.2 years, 9 out of 11 patients were females, and about two-thirds of tumours were in the left lung (8 out of 13). No patient developed carcinoid syndrome, but three patients had nonspecific respiratory symptoms. Bronchoscopy was not helpful in diagnosing any of these cases. Four patients required a wedge resection of the lung; the other six underwent lobectomy. One patient had tumours detected incidentally at autopsy. Mean tumour size was 2.39 cm (range 1.0-5.0 cm); four tumours were 3.0 cm or larger in diameter. Three cases (27.3%) had regional lymph node metastases, but no systemic metastasis was discovered. Apart from the patient who was discovered to have carcinoid tumours at autopsy, all others are alive and disease-free from 1 to 6 years after surgery.