ANATOMICAL VARIATION OF THE ESTROGEN-RECEPTOR IN THE NONNEOPLASTIC MYOMETRIUM OF FIBROMYOMATOUS UTERI

Myometrial tissues from a total of 30 normal and 30 fibromyomatous ute ri were compared in order to assess whether the oestrogen receptor dis tribution is similar for both types. All patients concerned were preme nopausal with no history of exogenous hormone usage. Material taken fr om the subserosal, midmyometrial and subendometrial regions of both th e fundus and the lower segment was stained by immunocytochemistry for the oestrogen receptor. No significant difference in the oestrogen rec eptor content was noted between the fundus and the lower segment in ei ther the normal or the fibromyomatous myometria. Similarly, the phase of the menstrual cycle did not affect the total receptor content of ei ther group of tissue. The oestrogen receptor content in the non-neopla stic portion of the fibromyomatous myometria was highest in the subend ometrial and lowest in the subserosal region. The differences in recep tor content between normal and fibromyomatous myometria were minimal i n the subendometrial region but marked in the subserosal region. The m yometrium of fibromyomatous uteri thus expresses significantly increas ed levels of oestrogen receptor, and the pathogenesis of fibromyomata may be related to an inherent abnormality in the myometrium.