Fig. 1

Haemorrhagic cyst. Patient presented to the emergency department with acute onset of lower abdominal pain. The patient had a previous history of a right oophorectomy for an ovarian serous tumour. Transvaginal ultrasound of the left ovary demonstrates a cyst with typical lacelike reticular internal echoes (large white arrow). There is no internal blood flow but circumferential blood flow around the cyst wall is seen (small white arrow); this is a typical feature in a haemorrhagic corpus luteal cyst