Primary choriocarcinoma and human chorionic gonadotrophin-producing giant cell carcinoma of the lung: are they independent entities?

Aims: Human chorionic gonadotrophin (hCG) is a useful marker for chorionic proliferative disorders, such as choriocarcinoma. Although hCG synthesis in lung cancers is frequent, primary pulmonary choriocarcinoma (PCC) is rare. To clarify the differences between primary choriocarcinoma and hCG-produci ng giant cell carcinoma (GCC) of the lung, we compared the clinicopathologi cal and immunohistochemical findings of these tumours. Methods and results: Three patients, one with PCC and two with hCG-producin g GCC, were included in this study. They were all middle-aged men and habit ual smokers. The growth of these tumours and the progression of the clinica l courses were extremely rapid, and the patients all died within 8 months a fter the pulmonary tumours were found. Haemorrhagic appearance was a common macroscopic feature of the specimens obtained. Microscopically, both types of tumours mainly consisted of atypical polygonal cells. While PCC contain ed many syncytial trophoblast-like multinucleated cells that had strong imm unoreactivity for anti-hCG, such cells were relatively few in hCG-producing GCC. These histological and immunohistochemical findings reflected the ser um test result for hCG, which was higher in the case of PCC. Conclusions: There are a few differences between PCC and hCG-producing GCC, as described above. Reliable distinction between them seems to be difficul t for pathologists and worthless for clinicians.