Pulmonary mucinous cystic tumor. Case report with review of the literature.

Mucinous cystic tumors of the lung are exceedingly rare. We describe the case of a 59-year-old white man with a left upper lobe mass documented on chest radiographs 11 years before thoracotomy. Grossly, the lobectomy specimen contained a 4.5 x 4.5 x 4.0 cm cystic gelatinous mass with complete occlusion of the anterior segmental bronchus by mucinous material. Although microscopically this pulmonary mucinous cystic tumor contained a focus of marked glandular atypia consistent with adenocarcinoma, the patient has remained free of recurrence or metastasis during 5 years of close postoperative follow-up. Pulmonary mucinous cystic tumors appear to have a remarkably favorable prognosis and should be distinguished from other common lung neoplasms.