Equine endometrial cytology.

The simplicity of collection of material for cytologic preparations belies the complexity of smear interpretation beyond recognition of neutrophils. Knowledge concerning cancer cytology moves rapidly, for cancer is a progressive, often fatal disease so that tissue for comparison and confirmation of interpretation often becomes available. This is not true for cytologic study of the equine endometrium. Lesions detected by means of cytology smears may be transient and regress, offering little information concerning their etiology or consequences. They may be focal and missed in the corresponding biopsy. Such experiences should lead to the abandonment of equine endometrial cytology, but have only strengthened our interest and enthusiasm for this technique in the study of the uterus. We have found it to be useful in a limited number of clinical circumstances in which other techniques have failed. This, plus the growing number of supportive clinicians using cytopathology service and the large number of mares with fertility problems, leads us to believe that further investigation of equine endometrial cytology may prove to be even more helpful as a clinical tool.