CHORIOCARCINOMA IN-SITU AT A FIRST TRIMESTER - REPORT OF 2 CASES INDICATING AN ORIGIN OF TROPHOBLAST OF A STEM VILLUS

Two cases of choriocarcinoma in situ arising in a first trimester plac enta are reported in a 28-year-old gravida 2, para 1, Japanese woman a nd a 38-year-old gravida 2, para 0. Both had a dilation and curettage (D and C) for vaginal bleeding and the absence of intrauterine fetus. No macroscopic abnormalities were noted in either case. However, histo logically, localized nodules of neoplastic trophoblastic proliferation measuring 5 mm in the first case, and 6 mm in the second appeared to arise directly from normal stem villi and project into the intervillou s space. Both tumours were composed of biphasic cytotrophoblast and sy ncytiotrophoblast. Fetal elements were not observed in either case. Ra diographic studies showed no metastatic lesions in either patient. Uri nary human chorionic gonadotropin levels were within normal range in b oth patients. The first patient had a normal full-term spontaneous vag inal delivery 22 months after the D and C and was free from disease wi thout therapy at 32 months. The second patient was free from disease w ithout therapy with a limited follow-up. These tumours provide evidenc e for an origin of choriocarcinoma from trophoblast of a stem villus. This report illustrates the need to perform thorough microscopic exami nation of the products of conception especially in the absence of a fe tus or fetal parts.