The unrecognized extragonadal germ cell cancer syndrome.

Within 3 years we saw 12 patients diagnosed initially as having poorly differentiated or undifferentiated carcinomas who, we believe, actually had extragonadal germinal cancers. Serum levels of the beta subunit of human chorionic gonadotropin (beta-HCG) or alpha-fetoprotein were useful in suggesting and supporting the diagnosis: Levels of one or the other were elevated in six of 10 patients in whom they were measured but levels of both, in only one patient. Staining of histologic specimens for beta-HCG or alpha-fetoprotein showed intracellular localization of one of these markers in the cancer cells of all four patients studied. All patients responded to therapy (11 treated with chemotherapy with or without radiotherapy, one with excision and radiotherapy only), with complete remissions in seven of 12. Two of the patients who had a complete remission have experienced relapse, and five have continued in disease-free remission from more than 8 to more than 56 months. Histologically atypical extragonadal germ cell neoplasms may be commoner than previously supposed. Physicians should consider this treatable and potentially curable cancer in selected patients having poorly differentiated or undifferentiated carcinomas.