LIPID-RICH RESIDUAL BODIES AND CATHEPSIN-D IN THE HUMAN UTERUS - ULTRASTRUCTURAL AND QUANTITATIVE COMPARISON BETWEEN NORMAL MYOMETRIUM AND LEIOMYOMA

The lipid-rich residual bodies (LRRB) (Eyden et al., 1991) in human my ometrium and uterine leiomyoma cells, have a distinctive ultrastructur e characterised by a rich lipid content. To evaluate the biological or pathological significance in detail, normal myometrium and uterine le iomyoma from 30 human cases were studied by conventional histological, histochemical, immunohistochemical and electron microscopic methods. The study included a quantitative analysis of LRRBs of 3 premenarchic cases, 19 cases having a menstrual cycle, and 8 cases in menopause, in addition to 20 patients with histologically conventional leiomyoma la rger than 3 cm in diameter. The study revealed the following findings: 1) immunohistochemical distribution of cathepsin D in the LRRB; 2) hi stochemical demonstration of neutral fat as the main content of LRRB; 3) statistically significant decrease in the distribution of LRRB in l eiomyoma tissue compared with normal myometrium; 4) an absence or mini mal distribution of LRRB in premenarchic myometrium; 5) a moderately s ignificant correlation between the frequency of LRRB and patient's age . The distribution of cathepsin D within LRRB and the differential exp ression of LRRBs in the various smooth muscle cell tissues of the uter us suggest a possible role of ovarian hormones in the genesis of LRRBs which may function in the intra-lysosomal degradation of organelles p roduced during hormonal cycling.