Primary adenoid cystic carcinoma of the lung. A clinicopathologic and immunohistochemical study of 16 cases.

BACKGROUND: Adenoid cystic carcinoma (ACC) is a rare but distinctive salivary gland-type malignant neoplasm that arises infrequently as a primary tumor in the lung.
METHODS: The clinical and pathologic features in 16 cases of primary ACC of the lung were reviewed, and immunohistochemical stains on paraffin sections were performed in 7 cases.
RESULTS: The patients' ages ranged from 29 to 79 years (mean age, 54 years); 11 were men and 5 were women. Clinically, most patients were seen initially with obstructive symptoms, including cough, wheezing, shortness of breath, and hemoptysis. Eight tumors were in the left lung and eight in the right lung. The lesions were treated by pneumonectomy in seven patients, lobectomy in six, and lobectomy plus chemotherapy in two. One patient was treated with chemotherapy alone after undergoing a diagnostic biopsy that revealed advanced disease. Grossly, most lesions were described as endobronchial and measured from 0.9 to 4.0 cm in greatest dimension; two cases, however, showed poorly circumscribed infiltrative tumors. Histologically, three main growth patterns were identified admixed in various proportions: cribriform (cylindromatous), tubular, and solid. Immunohistochemical study in six of seven cases showed a prominent myoepithelial cell component, as evidenced by immunoreactivity for keratin, actin, and S-100 protein in numerous tumor cells. Clinical follow-up ranging from 2 to 15 years in six patients showed that three were alive and well without evidence of recurrence or metastases at 5, 10, and 12 years, respectively, and three were alive with recurrence at 2, 5, and 15 years, respectively. Three other patients died of unrelated conditions at 2, 7, and 9 years, respectively, after diagnosis. Two patients in the study were seen initially with metastatic spread at the time of initial diagnosis and died 2 months and 1 year later with widespread metastases to lymph nodes, liver, spleen, kidney, and bone despite intensive chemotherapy.
CONCLUSIONS: Disease stage at the time of diagnosis may play an important role in predicting the clinical outcome of patients with these tumors. Despite their generally slow and indolent growth in other locations, ACC arising in the lung may in certain cases be more aggressive.