Sclerosing haemangioma of lung--case report with histologic, immunohistochemical and ultrastructural correlation.

We report a case of a large sclerosing haemangioma of the lung that was found incidentally on roentgenography of an asymptomatic woman presenting for routine health screening. Computed tomographic scan showed a well-defined "coin" lesion with peripheral foci of calcification. The lesion had a variegated histological appearance comprising four major patterns--solid, papillary, haemorrhagic and sclerotic. There appeared to be two populations of cells--distinct round cells with abundant clear cytoplasm constituting the solid component and uniform cuboidal cells with small, dark nuclei lining irregular spaces. Positive immunohistochemical staining for cytokeratin and epithelial membrane antigen, and the ultrastructural demonstration of epithelial characteristics and electron-dense bodies showed that the proliferating cells had features in keeping with type 2 pneumocytes. This is a benign condition and the prognosis is excellent.