corpus hemorrhagicum

The corpus hemorrhagicum is a transient blood-filled structure that forms in the ovary immediately after the rupture of a mature follicle during ovulation. It is created when small blood vessels in the follicle wall bleed into the collapsed follicular cavity, forming a clot that will subsequently be remodeled into the corpus luteum.

The corpus hemorrhagicum is located within the ovary, at the site where a dominant follicle has just ruptured. It occupies the space left by the evacuated follicular fluid and develops on the surface of the ovary, typically visible as a small hemorrhagic cyst during surgical or laparoscopic inspection.

The corpus hemorrhagicum serves as an intermediate transitional structure in the ovarian cycle. The blood clot it forms acts as a scaffold that is rapidly organized and vascularized to form the corpus luteum — the endocrine structure responsible for producing progesterone to support the early luteal phase and potential early pregnancy.

The corpus hemorrhagicum may be associated with excessive or persistent bleeding, leading to a larger hemorrhagic ovarian cyst that may cause pelvic pain. On ultrasound it may occasionally be mistaken for other ovarian cysts or ectopic pregnancy. Rupture of the corpus hemorrhagicum may be associated with significant intraperitoneal bleeding in some cases.

The corpus hemorrhagicum is typically identified on pelvic ultrasound as a complex cystic structure with internal echoes representing blood clot. It may also be seen on MRI. Histological examination of surgically removed tissue shows a blood-filled cavity surrounded by granulosa and theca cells undergoing luteinization.