[Adenoid cystic carcinoma (cylindroma) of the bronchi]

Cytological, histological, and ultrastructural examinations of 6 cases of adenoid cystic carcinoma of the bronchi were carried out. Cytological studies demonstrated cells of two types: smaller, rounded or slightly elongated cells with hyperchromic nuclei and scarce basophilic cytoplasm, and larger cells with clear nuclei and basophilic, slightly vacuolated cytoplasm. The cells are located among oxyphilic homogeneous substance. Histologically the tumour has a typical cribrose appearance owing to glandular-like and cyst-like cavities among alveolar cell aggregates embedded into intensely developed but poor in cells and somewhat hyalinized stroma. The invasive growth of the tumour with its extension into the depth of the lung on interalveolar septae, perivascular and peribronchial spaces with outgrowth of the capsule was manifest in all cases. Electron microscopic studies showed the tumour elements to be lowly differentiated epithelial cells. No ultrastructural signs of myothelium or secretory mucous activity was found. The results of these studies indicate that this tumour should be designated as adenoid cystic carcinoma but not adenoma of cylindromatous type.