[Clinicopathological and immunohistochemical features of pulmonary blastoma: analysis of 4 cases and review of the literature].

Objective To analyze the clinicopathological and immunohistochemical features of pulmonary blastoma(PB).Methods Four patients with PB,1 male and 3 females,with the onset age of 2 months～80 years,underwent resection of the tumor and were followed up for 32 months at most.The clinical data were analyzed retrospectively.Results Pathology showed that the 4 cases all suffered from epithelial type PB.Under microscope,epithelial cells were atypical,mostly in mitogenic phase,and were lined up as many dense tubes.All of the patients underwent surgical resection and 3-5 cycles of chemotherapy and one had radiotherapy following surgery.The survival time was 5-32 months.One of the four patients died during follow-up due to metastasis 5 months after operation.The other patients still survived.Immunohistochemistry showed that cytokeratin and thyroid transcription factor-1 were positive,and vimentin,epithelial membrane antigen,and S-100 protein were negative in the tumor tissues;and a part of tumor cell presented positive Cg- A.Conclusion PB is rare and presents different clinical features.It is difficult to determine the diagnosis before operation.The morular structures and expression of neuroendocrine markers are helpful in differentiating epithelial type PB from usual adenocarcinoma in immunohistochemical staining.