Fine-needle aspiration cytology of bronchial acinic cell carcinoma: a case report

Salivary gland-type carcinomas of the lung are rare but well-known tumors. Among them, acinic cell carcinoma (ACC) is extremely rare and its cytological features have not been reported. We present a case of bronchial ACC and describe its cytological characteristics. The tumor occurred in a 58-yr-old man as a 15-mm polypoid lesion at the right middle lobar bronchus and filled its lumen. Transbronchial brush cytology and a biopsy failed to collect tumor cells but transbronchial fine-needle aspiration (FNA) cytology was successful. The smear obtained was richly cellular and a large number of thick-layered or monolayered sheet-like tumor cell clusters and dissociated tumor cells were observed. Cribriform globular spaces were common and a lobulated acinar structure was found focally. The tumor cells had a fine granular large polygonal cytoplasm and rather uniform round or ovoid nuclei. The nuclei were situated eccentrically or centrally and the nuclear/cytoplasmic ratio was consistently low. These cytological features were essentially similar to those of ACC of the head and neck region. The patient underwent a lobectomy and the tumor was resected completely. Transbronchial FNA cytology was useful for diagnosing bronchial ACC and differentiating it from other conventional and salivary gland type carcinomas.