Cytomorphology of carcinoid tumors

This report is based on a review and study of carcinoid tumors as seen in smears prepared from exfoliative or aspiration smears. During a period of eight years (1970 to 1978), 236 cytologic specimens were examined from 64 patients treated for carcinoid tumors at Memorial Hospital. Thirty-eight cytologic specimens from 18 patients were interpreted as either suspicious or positive for malignant cells. Tumor cells were identified most often in tracheobronchial specimens, effusions and percutaneous aspirates. A striking similarity in cell morphology was found between exfoliated and aspirated tumor cells. Certain specific or suggestive cytologic features were recognized. The histogenesis of carcinoids and the role of intracytoplasmic neurosecretory granules in the differential diagnosis is discussed together with the clinicopathologic implication of positive cytologic findings.