Ovarian hyperstimulation syndrome in a spontaneous pregnancy with invasive mole

Spontaneous ovarian hyperstimulation syndrome (sOHSS) is an extremely rare event. Herein, we report a case of severe sOHSS with invasive mole in a 29-year-old woman. In this case the full-blown OHSS developed after evacuation when the serum β-hCG value was declining. Also noticeable was a very high level of cancer antigen-125. Molecular biology study of the follicle-stimulating hormone (FSHR) gene did not detect exonic mutations, but revealed the presence of c.-29G>A (rs1394205) in the 5'-non-coding region of exon 1. The A307T and S680N polymorphisms of exon 10 of FSHR was Thr307 Asn680. Although sOHSS is a rare entity, clinicians must bear the differential diagnosis of sOHSS in mind if a patient presents with gross ascites and other symptoms of ovarian cancer, which also may be signs of OHSS. Whether the single nucleotide polymorphism rs1394205 affects the level of transcriptional activity of the FSHR gene needs to be studied in the future.