Recurrence of pulmonary mucinous cystic tumor of borderline malignancy.

Cystic mucinous tumors of the lung are recently described neoplasms whose histology is different from most lung adenocarcinomas, and represent a spectrum of malignant potential. Little is known of the behavior of the more malignant subtype. We present a cystic mucinous tumor of borderline malignancy that recurred locally following initial limited resection, and was treated with lobectomy.