[Pulmonary oncocytic carcinoid--a case report]

A pulmonary oncocytic carcinoid arising from the medial basal segment of the right lung is presented. The abundant oncocytic granules in the cytoplasm were observed by light-microscope. The ultrastructure by electronmicroscope showed that these granules originated from the hyperplasia of mitochondria, and there were membrane-bordered electric dense core granules (neuro-secretive granule) in the cytoplasm of this tumor. According to the morphological features observed by light and electronmicroscope, this tumor is considered as a subtype of bronchial carcinoid and belongs to the APUD system which should be differentiated from the metastatic tumor, the granular cell myoblastoma and the chemodectoma of lung.