Detection of endometrial pinopodes by light microscopy

Objective: To study the value of light microscopy (LM) in the assessment of endometrial pinopodes. Design: Comparative histologic study. Setting: Outpatient infertility clinic in an academic teaching institution. Patient(s): Eighteen oocyte donors undergoing controlled ovarian hyperstimu lation. Intervention(s): Endometrial biopsies on days 14-24 of the cycle. Main Outcome Measure(s): Assessment of pinopodes by scanning electron micro scopy (SEM) and of endometrial surface projections by LM. Result(s): The luminal surface was identified by LM in 36 of 38 endometrial specimens obtained. Although apical projections could be recognized in all , they were few, moderate, and abundant in 20, 12, and 4 cases, respectivel y. Pinopodes were detected by SEM in all 4 samples with abundant projection s, but in only 14 of 32 samples with lesser quantities of these surface fea tures. No predictive value could be ascribed to apical projections viewed b y LM for the developmental stage of pinopodes as defined by SEM. Conclusion(s): The LM of routine endometrial specimens can serve as a preli minary tool in the evaluation of surface morphology. Although abundant apic al projections by LM are compatible with the presence of pinopodes by SEM, the latter modality remains as the definitive method in cases with few or m oderate projections and for the evaluation of the stage of pinopode develop ment. (Fertil Steril (R) 2000;74:767-70. (C) 2000 by American Society for R eproductive Medicine.).