Peripheral low-grade mucoepidermoid carcinoma of the lung--needle aspiration cytodiagnosis and histology.

Mucoepidermoid carcinoma of the lung is a rare tumour, and is not usually considered in the differential diagnosis of a peripheral lung mass. The cytological and histological features of an intimate admixture of polygonal intermediate cells, well differentiated mucinous and squamous cells, as illustrated in this case report, serve to differentiate a well differentiated mucoepidermoid carcinoma from adenosquamous carcinoma, low grade adenocarcinoma, bronchioloalveolar carcinoma, and benign reactive changes.