A diagnosis of choriocarcinoma was made by the biopsy of a solitary nodule in the scalp of a 29-year-old asymptomatic woman. Choriocarcinoma is a malignant tumor that arises from the fetal trophoblast; it commonly occurs in women after molar pregnancy or miscarriage. Histological findings are the presence of two cell types, cytotrophoblast and syncytiotrophoblast, that grow in a plexiform pattern resembling the primitive unbranched chorionic villi of the 13-day ovum. The tumor's ability to secrete chorionic gonadotropin allows a method for follow-up of patients. With the introduction of chemotherapeutic agents, the previously poor prognosis has been reversed with at least 80% of all patients responding to therapy.
Cosnow I, Fretzin DF. Choriocarcinoma Metastatic to Skin. Arch Dermatol. 1974;109(4):551-553. doi:10.1001/archderm.1974.01630040057015