MORPHOLOGIC AND IMMUNOPHENOTYPIC CHARACTERIZATION OF FOAM CELLS IN ENDOMETRIAL LESIONS

The detection of foam cells In cervicovaginal smears obtained from pos tmenopausal women suggests the possibility of an endometrial lesion. U ltrastructural studies have suggested that foam cells represent endome trial stroma; cells but the histogenesis of these cells has not been f irmly established. To investigate the origin and diagnostic significan ce of foam cells, we analyzed the morphology and immunophenotype of th ese cells in endometrial tissue specimens and correlated the findings with cervical smears obtained within the preceding 6 months. Selected biopsies containing foam cells were evaluated using four well-characte rized macrophage markers: KP-1(CD68), HAM 56, MAC 387, and lysozyme. F oam cells were found in 11 (38%) of 29 simple hyperplasias, 7 (50%) Of 14 complex hyperplasias, 6 (50%) of 12 complex atypical hyperplasias, 21 (70%) of 30 adenocarcinomas, 1 (44%) of 25 samples with stromal br eakdown, and 0 of 30 specimens showing normal cycling endometrium. Foa m tells were also found in smears preceding the histologic diagnosis o f 2 (13%) simple hyperplasias, 2 (25%) complex hyperplasias, 3 (43%) c omplex atypical hyperplasias, 5 (28%) adenocarcinomas, 5 (28%) cases o f stromal breakdown, and 0 of 8 normal tissue specimens examined. Foam cells were Immunoreactive with at least 2 of the 3 macrophage-specifi c antibodies in all 21 biopsies studied. Our results suggest that foam cells phenotypically represent macrophages and not endometrial stroma l tells. Foam cells are identified in a significant percentage of cerv ical smears and endometrial tissue specimens obtained From women with endometrial pathology. The morphology and immunophenotype of foam cell s, however, does not appear to be useful in distinguishing benign endo metrial stromal breakdown, endometrial hyperplasia, and endometrial ad enocarcinoma.