Fine needle aspiration biopsy of peripheral congenital bronchial cyst.

Bronchial cysts usually occur centrally near the mediastinum, but may present as a peripheral "coin" lesion requiring distinction from other causes of coin lesions of the lung. A case is reported in which fine needle aspiration (FNA) biopsy was used to make the diagnosis of such a peripheral bronchial cyst. FNA produced an opaque opalescent fluid; cytologic study of the smears showed abundant bipolar birefringent needle-shaped crystals an a few macrophages. Neither special staining of some smears nor cultures of part of the aspirate revealed the presence of any organism. The cytologic diagnosis was confirmed by histologic examination of the subsequent resection specimen.