massive ovarian oedema (MOO)

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Massive ovarian edema (MOO) is a very rare disease characterized by a tumor-like, usually unilateral, enlargement of the ovary.

Epidemiology

It characteristically presents in young women ~ 6 to 33 years (mean age ~21 years ).

Clinical presentation

Most patients present with intermittent pelvic pain of several months duration +/- an adnexal mass. Abnormal uterine bleeding, elevated androgens and abdominal distension can occasionally be seen.

Pathology

The most probable cause is thought to be recurrent partial torsion of the mesovarium, with obstruction to the venous and lymphatic returns; on the other hand, the basic process may be stromal hyperplasia or hyperthecosis, while the edema is a secondary phenomenon, probably due to torsion of an abnormal, already enlarged organ.

Associations
  • Meig syndrome
  • precocious puberty in infants due to MOO has been described in the literature 
Location

It is almost always unilateral and in approximately two-thirds of cases involve the right side.

Radiographic features

The imaging features correspond to the degree of torsion and edema. As MOO is caused by chronic or intermittent torsion, imaging appearances will have some overlap with those of ovarian torsion.

Ultrasound

May appear like a hypoechoic, hypovascular solid ovarian mass-like lesion; there is the presence of central increased ovarian stroma, and there are multiple follicles arranged in the peripheral cortex.

MRI

MRI may also demonstrate an enlarged ovarian mass-like lesion. Described signal characteristics include  :

  • T1: hypointense
  • T2: hyperintense
  • T1 C+ (Gd): may show enhancement 

Treatment and prognosis

Management options include oophoropexy and occasionally oophorectomy is also considered.

History and etymology

The term massive ovarian edema was first described by Kalstone in 1969.

Differential diagnosis

See also

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