[Primary choriocarcinoma of the lung. Three cases in men].

Choriocarcinoma of the lung was recorded from three males, twice by autopsy and once by biopsy. Its histogenetic aspects are discussed in some detail. High levels of human choriogonadotropin (HCG) were recorded from blood serum and urine. The presence of this hormone in the syncytiotrophoblast and that of carcinoembryonic antigen (CEA) in the cytotrophoblast was positively verified by means of immunofluorescence. Granules of HCG were recordable electron microscopically from cytoplasm of the syncytiotrophoblast.