Adenocarcinoma arising in an extralobar sequestration: a case report and review of the literature.

Extralobar sequestration is a type of bronchopulmonary foregut malformation defined as an isolated portion of lung tissue with a systemic arterial supply, its own pleural investment, and no bronchial communication. While it may be recognized in utero or in the neonatal period, depending on its location and associated anomalies, it can also go unrecognized until later in life when it may present as a mass. We report the first case of adenocarcinoma arising in an extralobar sequestration. The patient was a 70-year old man with a 55 pack year smoking history who presented with chest discomfort and was found to have a 6.5 cm right lower lobe mass. Percutaneous biopsy of the mass was positive for adenocarcinoma. At surgery, the mass was noted to have a separate arterial connection, no bronchial communication, and its own pleural investment, consistent with an extralobar sequestration. Malignancy arising in pulmonary sequestrations is rare and the few reported cases have been in intralobar types. Carcinoma arising in this setting adds to the dilemma of whether or not these developmental anomalies should be excised or followed. Our tumor, while small, did have vascular invasion.