A rare case of classic biphasic pulmonary blastoma.

Biphasic pulmonary blastomas are rare tumors that together with pulmonary carcinosarcomas comprise less than 2 per cent of all lung neoplasms. They can be defined as tumors that are composed of an admixture of immature mesenchyme and epithelium and that recapitulate morphologically the embryonal structure of the lung. First described in 1945 by Barnett and Barnard, their existence is well documented although their occurrence is rare. We present a case of a 40-year-old Hispanic female that presented with a 2-month history of retrosternal and midepigastric pain. A GI etiology was initially treated unsuccessfully with antireflux medications. A chest radiograph showed a 4.6-cm mass in the right upper lobe of the lung, and computed tomography showed right apical bullous formation with no lymphadenopathy. Bronchoscopy revealed no endobronchial lesions, and biopsy was nondiagnostic. The histopathologic and immunophenotypic analysis of a right upper lobectomy specimen was diagnostic of classic biphasic pulmonary blastoma. The rarity of these tumors makes easy identification difficult. Immunohistochemical analysis must be used to arrive at the proper diagnosis. It is imperative that there be good communication between the surgeon and pathologist and that institutions have access to facilities with the ability of identifying these complex tumors.