Infant pleuropulmonary blastoma: report of a rare case and review of literature.

In infants, pleuropulmonary blastoma is a rare but aggressive tumor. The typical histopathological presentation includes the aggregation of malignant primitive small cells, usually observed in sheets. So as to provide proper and timely treatment, the differential diagnosis includes pulmonary blastoma, sarcomatoid mesothelioma, fetal rhabdomyoma, synovial sarcoma, and primitive neuroectodermal tumor. Herein, we will present one male pediatric patient with pleuropulmonary blastoma. The patient was a 4-month-old male infant, who had a prolonged cough and dyspnea for 4 months that was complicated by cyanosis for 3 days. A physical examination revealed a solid mass in the right lung that was sized 9.0 × 6.0 × 4.0 cm and had a grayish-white cross section. The boundary between the mass and lung tissue was clear; the mass already occupied a great portion of the lung. A microscopic examination suggested that the tumor was composed of round or orbicular-ovate primitive fetal cells. The cells were medium sized, having little cytoplasm, but had a clearly visualized nucleolus and active karyokinesis. The tumor mass was biphasic, namely, fasciculated sarcoma (composed of spindle-shaped cells and short spindle-shaped cells) and malignant fibrous histiocytoma containing well-differentiated cartilage islands or cartilaginous nodes. Immunohistochemistry was performed for further detection: vimentin (+), S-100 protein (+), CK (AE1/AE3), EMA and TTF-1 in residual epithelial components (+), NSE (focal +), SMA (mesenchymal cells, focal +), CD99 (weak +), Bcl-2 (weak +), desmin (-), myoglobin (-), calretinin (-), calponin (-), FLI (-), MyoD-1 (-), and CD34 (-). Pleuropulmonary blastoma is extremely rare but highly aggressive neoplasm in children. Its typical histopathological presentation is the aggregation of primitive malignant small cells. Combining imaging and histopathological examinations and clinical data should help in determining the diagnosis of pleural pulmonary blastoma.