Background: Nongestational choriocarcinomas are aggressive tumours occurring either as a global event or as a focal change in solid tumours. The latter is responsible for coexistence of trophoblastic histology with other malignancies.
Case: A 65-year old female with stage IV primary peritoneal carcinoma, ovarian type, underwent surgical cytoreduction followed by two courses of paclitaxel/carboplatin chemotherapy. A choriocarcinomatous component was later identified in the resection specimens, as chemotherapy resulted in a differential response of the two malignant variants. Commencement of EMA/CO chemotherapy (etoposide, methotrexate, actinomycin D, cyclophosphamide, vincristine) resulted in symptom palliation and tumour regression, further consolidated with platinum-based EP/EMA (etoposide, cisplatin, methotrexate, actinomycin D). Two months later, relentless choriocarcinomatous disease progression followed, leading to the patient's death while the peritoneal adenocarcinomatous variant remained biochemically quiescent.
Conclusion: Choriocarcinomas may coexist with typical ovarian-type peritoneal cancer, creating diagnostic and therapeutic dilemmas. Aggressive weekly chorio-type chemotherapy appears to be warranted despite the low likelihood of cure, as it provides significant symptom palliation.