Amphicrine carcinoma of the lung. Diagnosis by fine needle aspiration cytology.

A case of pulmonary carcinoma with dual (glandular and endocrine) differentiation diagnosed by fine needle aspiration cytology is reported. By light microscopy, the neoplastic cells showed mucicarmine, periodic-acid Schiff, and Grimelius silver positivity. On immunostaining, neuron specific enolase, chromogranin, calcitonin and serotonin were demonstrated. Electron microscopy revealed two different types of distinctive cytoplasmic inclusions in the same cell, namely: carcinoid type of neurosecretory granules and mucin droplets. Diagnostic criteria and possible histogenesis of this rare tumour entity are discussed.