Endobronchial variant of sclerosing hemangioma of the lung:: histological and cytological features on endobronchial material

We report two cases of a rare presentation of pulmonary sclerosing hemangioma as an endobronchial polyp resulting in clinical symptoms of bronchial obstruction. We describe the histological and cytological description of this entity based on material obtained during bronchoscopic examination. In both cases, bronchoscopy revealed a polypoid mass protruding into the left lower lobar bronchus, with a smooth and hemorrhagic surface, reminiscent of a carcinoid tumor. On bronchial washing in case 1, numerous small round cells were seen with uniform nuclei and inconspicuous nucleoli, arranged in clusters with a pavement-type pattern and papillary configuration. The presence of a few reactive pneumocytes gives a dual cell proliferation, in a background of numerous foamy macrophages. Although the four architectural patterns of sclerosing hemangioma were present in the resected tumors, the papillary and solid patterns predominated in the endobronchial component of the tumors and these were seen on the bronchial biopsies. Recognition of the papillary pattern, the typical round cells coexpressing thyroid transcription factor-1 and epithelial membrane antigen without cytokeratin immunoreactivity, are helpful clues for the diagnosis on bronchial biopsy. Finally, hopefully awareness by clinicians and pathologists that sclerosing hemangioma can present as an endobronchial mass will facilitate diagnosis when this rare event occurs.