Fine needle aspiration of adenoid cystic carcinoma metastatic to the lung. Cytologic features and differential diagnosis

Abstract

Two examples of adenoid cystic carcinoma metastatic to the lung, one from a Bartholin's gland and the other from a submandibular gland, were sampled by fine needle aspiration. Although the cytologic features of adenoid cystic carcinoma have been well described, it is easy to confuse adenoid cystic carcinoma with other more common primary small-cell neoplasms of the lung; to determine distinguishing features, we compared the cytomorphology of adenoid cystic carcinoma with well-differentiated adenocarcinoma, small-cell undifferentiated carcinoma and carcinoid tumor of the lung. The differential features distinguishing adenoid cystic carcinoma from these other neoplasms include: (1) tight, globular, honey-comb arrangements of cells lacking true nuclear molding; (2) acellular chunks of basal lamina material, which alone may suggest adenoid carcinoma; and (3) the extension of a solid core of basal lamina material beyond a sievelike cellular meshwork. The morphologic expression of metastatic adenoid cystic carcinoma is so distinctive as to permit a definite diagnosis.