Objective: To investigate the biologic significance of thyroid transcription factor-1 (TTF-1) and surfactant protein A (SP-A) and SP-B expression in pulmonary sclerosing hemangioma (PSH).
Methods: TTF-1, SP-A, SP-B, epithelial membrane antigen (EMA), pancytokeratin (AE(1)/AE(3)), vimentin, CK7, CK5/6, calretinin, S-100, neuron specific enolase (NSE), synaptophysin (Syn), chromogranin A (CgA), CD(34), Factor VIII and smooth muscle actin (SMA) in 42 patients with PSH were examined with immunohistochemistry, while samples from 10 patients were also observed by electron microscope.
Results: Histopathologically, PSH mainly consisted of both surface lining cuboidal cells and pale polygonal cells. Both of them were stained with TTF-1, EMA and vimentin, whereas SP-A, SP-B, pancytokeratin and CK7 were only positive in surface lining cuboidal cells. Syn, NSE, S-100 and CgA showed scattered positivity in these cells. There was no significant difference in the expressions of TTF-1 and EMA between these two cell types (P > 0.05), whereas the difference was significant in the expression of vimentin (P < 0.01). The ultrastructural features cannot differentiate these two cells by electron microscope.
Conclusions: It is suggested that PSH is derived from primitive respiratory epithelium, and both surface lining cuboidal cells and pale polygonal cells were entity cells of the tumor. Examination of different immunohistochemical markers including TTF-1, SP-A, SP-B, pancytokeratin, EMA and vimentin is helpful in the diagnosis and differential diagnosis of PSH.