Ruptured corpus luteum cyst

Case contributed by Dr Vikas Shah


Sudden onset abdominal pain. Diffuse tenderness and guarding. Pregnancy test negative. Ultrasound showed right adnexal mass and free fluid. CT to evaluate for malignancy.

Patient Data

Age: 30 years
Gender: Female

There is a large volume of high density fluid throughout the abdomen in keeping with a hemoperitoneum. There is a mixed density 5 cm "mass" in the region of the right ovary. This is surrounded by a large volume of high density fluid in keeping with a possible sentinel clot.

Annotated image

Density of fluid on CT

Hounsfield units (HU) are a measure of density on CT. Water has a HU of 0. Free fluid, often having some cellular material within it, has a HU just above 0. Fresh liquid blood has a HU slightly lower (30-45) than blood that has clotted (45-70). The clot is often a clue to as the site of bleeding (sentinel clot). Following a period of red cell lysis and clot organization, the HU measurement falls. A lower HU is also seen in anemia.

Case Discussion

The differential of a spontaneous hemoperitoneum in a young female is between ruptured corpus luteum cyst or ruptured ectopic pregnancy, with the beta HCG test being an important differentiator as they can look identical on imaging studies. At surgery, a ruptured corpus luteum cyst was confirmed.



Clinical history: Bleeding right ovarian cyst. Right salpingo-oophorectomy.

Macroscopic description: Right ovary and Fallopian tube. Ovary 49x35x12mm and contains ruptured cystic area 25x20mm. Attached Fallopian tube 50x5x5mm

Microscopic description: The ovary contains an enlarged, degenerate corpus luteum, amounting to a luteal cyst. The background ovary and Fallopian tube are unremarkable.

Conclusion: Right ovary and Fallopian tube - luteal cyst

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Case information

rID: 54789
Published: 28th Jul 2017
Last edited: 29th Jun 2020
System: Gynaecology
Inclusion in quiz mode: Included

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