Heterotopic pancreatic tissue presenting as a solid and cystic lung lesion: a very unusual bronchopulmonary foregut malformation.

We describe the history and lung pathology of a premature female infant, who presented with respiratory distress immediately after birth. A thoracic computerized tomography scan showed abnormalities suggestive of congenital cystic adenomatoid malformation of the left lung. In addition, echocardiography revealed a tetralogy of Fallot. A left thoracotomy was performed and the lower lobe of the left lung was removed. Despite intensive supportive therapy, pulmonary hypoperfusion resulted in severe hypoxemia and death. Gross and microscopic analysis of the resected lobe revealed a partly cystic and solid lesion with multiple bronchus-derived cysts and an exuberant multifocal proliferation of glandular tissue, resembling bronchial glands, mixed with heterotopic cartilage surrounding ducts. Immunohistochemical analysis showed the presence of chromogranin A-reactive islet-like structures amidst exocrine tissue showing trypsin and chymotrypsin immunoreactivity, establishing the diagnosis of pulmonary pancreatic heterotopy. In the remaining pulmonary parenchyma, there were secondary changes consistent with partial obstruction and lymphangiectasis which was attributed to the presence of the cardiac malformation. To our knowledge, this is only the fourth reported case of heterotopic pancreatic tissue in the lung, and the first case where this bronchopulmonary foregut anomaly is not associated with a enteric duplication.