theca lutein cyst
They are thought to originate due to excessive amounts of circulating gonadotrophins such as beta-hCG. Hyperplasia of the theca interna cells is the predominant characteristic on histology. The ovarian parenchyma is often markedly edematous and frequently contains foci of luteinized stromal cells.
- they have a very high association with gestational trophoblastic disease.
Other reported associations include:
- multifetal pregnancy
- polycystic ovarian syndrome (PCOS)
- diabetes mellitus
- clomiphene intake
- ovulation induction
- pregnancy with background chronic renal failure
- normal uncomplicated pregnancy
The clinical context is vital in correct imaging interpretation.
The cysts are usually large (2-3 cm) and the ovaries often have a typical multilocular cystic appearance across all imaging techniques .
Bilateral enlarged, multicystic ovaries. The cysts are classically thin walled and have clear contents. There is large amount of solid component which is possibly the residual ovarian stroma.
Typically seen as bilateral (occasionally unilateral) ovarian enlargement with multiple cysts which are generally of uniform size.
The residual parenchyma within the enlarged ovaries have been reported to show
- T1 C+ (Gd): intense contrast enhancement
- T2: intermediate signal intensity
- DWI: high signal
Treatment and prognosis
Following evacuation of a molar pregnancy, the associated theca lutein cysts resolve by 2-4 months.
There are cases reported of nomal pregnancies associated with hyperreactio leutinalis which have resolved gradually post delivery.
Surgical emergency is only if ovarian torsion occurs.
For large multiple bilateral ovarian cysts consider
- ovarian hyperstimulation syndrome: can also be an association
- often has a history of ovulation induction
- may have free pelvic fluid
- mucinous ovarian malignancy
- a more solid component may be present noted
- ovarian tumor markers +/- beta HCG levels may be elevated