Microscopic appearance shows a cyst lined by inner granulose cell layer and outer theca interna cell
The P450 s enzyme (CYP11A1) is present in the internal membrane of the mitochondria converting cholesterol into pregnenolone, mainly in the theca interna cells
Histologically, cysts are filled with clear to blood-tinged fluid or clotted blood with a smooth lining composed of an inner layer of granulose cells and an outer layer of markedly luteinized and hypertrophic theca interna cells
Microscopic examination reveals well-circumscribed nodules of steroid hormone-producing cells, intermediate in size between luteinized granulosa cells and luteinized theca interna cells.
Pregnancy luteomas are generally thought to arise from nodular hyperplasia of theca interna cells (theca-lutein hyperplasia), (59,67,69) although others (56) have proposed an origin from stromal cells.
The theca interna cells rest upon a thin basement membrane.
The remaining granulosa and theca interna cells undergo transformations and re-organize to form a corpus luteum, or "yellow body.
Moreover, nicotine has been shown to inhibit the induction of progesterone synthesis in cumulus cells by FSH and the production of other androgens by theca interna cells
During follicle selection, LH acts on theca interna cells to promote conversion of cholesterol to testosterone.
Theca interna cells remain unchanged but some of the capillaries contain coagulated blood causing petechia on the surface of the follicle.
The major morphologic changes induced by the LH surge involve transforming the residual granulosa and theca interna cells
into large and small luteal cells, respectively (Figure 12-5).
Small luteal cells Hormone-producing cells of the corpus luteum that are derived from theca interna cells
of the follicle.