[Testicular choriocarcinomas masked by predominating seminomas].

Testicular choriocarcinomas may be disguised by the histological appearance of pure seminomas with apparently normal HCG levels. As demonstrated by the 5 cases reported here, a definite diagnosis by further histological specimens, more often by the development of abnormal HCG levels, may be delayed. Early chemotherapy appears to offer the best chance to such patients. Suspicious signs: HCG levels at the limit of normal before castration, suspect histology (marked hypertrophy of the interstitial gland, zones of necrosis, an unusual clinical appearance with large lymph node lesions, an unusual course with early lymph node or metastic recurrences, may suggest the presence of choriocarcinoma and lead to routine chemotherapy.