Calretinin and CD34 immunoreactivity of the endometrial stroma in normal endometrium and change of the immunoreactivity in dysfunctional uterine bleeding with evidence of 'disordered endometrial stroma'.

AIMS: We investigated the pattern of reactivity of calretinin and CD34 in normal and pathological endometria. METHODS: Various endometrial tissues were submitted for calretinin and CD34 immunostaining. RESULTS: Calretinin reactivity was limited to the endometrial stromal cells (ESC) of the superficial zone of the functionalis layer (FL) in the proliferative phase, and was extensive in all stages of the secretory phase. The ESC of the post-menopausal, ectopic, hyperplastic or neoplastic endometria showed negative or focal weak reactivity for calretinin. In dysfunctional uterine bleeding (DUB) with a normal or an abnormal histopathological appearance on routine stain, there were varying degrees of focal to extensive decreases in calretinin reactivity. The foci of negative calretinin reactivity in the FL displayed varying reactivity for CD34 and appeared to be continuous with the basalis layer (BL). Endometrial polyps were often reactive for CD34, but not reactive for calretinin. CONCLUSIONS: Immunostaining for calretinin and CD34 is helpful in the diagnosis of endometrial polyp and hyperplasia. In DUB, with or without abnormal histopathological findings, there were alterations of the zonal pattern of calretinin reactivity in the FL. This alteration appears to be an expansion of the stroma of the BL into the FL, resulting in a 'disordered endometrial stroma'.

Calretinin: an immunohistochemical marker for the normal functional endometrial stroma and alterations of the immunoreactivity in dysfunctional uterine bleeding.

Calretinin has been identified in the central nervous system, in various endocrine and mesothelial cells, and is often used as an immunohistochemical tool in the pathologic diagnosis. We have recently observed its presence in the endometrial stromal cells (ESC) of the normal functionalis (FL). Endometrial tissue from various physiologic and pathologic conditions was submitted for immunostaining for calretinin. For each condition, two to ten samples were tested. Calretinin displayed a strong cytoplasmic and occasionally nuclear reactivity for ESC of the normal FL in all physiologic phases of the normal menstrual cycle except for the breakdown period. Reactivity was limited in the superficial zone of the FL in proliferative phase, and was extensive in all stages of secretory phase. The ESC of the basilis layer, postmenopausal women, endometriotic and adenomyotic tissue, endometrial polyps, hyperplasia, carcinoma, and ESC neoplasms were not reactive for the marker. In endometrial specimens from patients with dysfunctional bleeding, there were varying degrees of decrease in reactivity in a patchy pattern. We demonstrated for the first time that calretinin reactivity of the ESC is strong and diffuse in a zonal pattern in the normal FL of the normal cycling endometrium. In endometrium with dysfunctional bleeding, postmenopausal, ectopic, hyperplastic, and neoplastic endometria, the ESC displayed focally decreased to negative reactivity. Calretinin can be used as a marker for normally functional ESC. Further study is necessary to investigate the mechanism and the role that calretinin plays in the physiologic cyclic changes of the endometrium.