Diagnosis of Endometriosis

Robert Z. Spaczynski, MD, PhD, Antoni J. Duleba, MD


Semin Reprod Med. 2003;21(2) 

In This Article

Abstract and Introduction


Endometriosis is a common disorder of women of reproductive age, yet diagnosis of this condition is often problematic. The most frequent clinical presentations of endometriosis include dysmenorrhea, pelvic pain, dyspareunia, infertility, and pelvic mass. However, the correlation between these symptoms and the stage of endometriosis is poor. Currently available laboratory markers are of limited value. At present, the best marker, serum CA-125, is usually elevated only in advanced stages and therefore not suitable for routine screening. Transvaginal ultrasound and magnetic resonance imaging are often helpful, particularly in detection of endometriotic cysts. Recently, transrectal ultrasound and magnetic resonance imaging were shown to be valuable in detection of deep infiltrating lesions, especially in the rectovaginal septum. Although direct assessment of endometriotic foci at laparoscopy may be viewed as a "gold standard" for identifying endometriosis, the correlation of laparoscopic observations with histological findings is often low. Ultimately, diagnosis of endometriosis requires a careful clinical evaluation in combination with judicious use and critical interpretation of laboratory tests, imaging techniques, and, in most instances, surgical staging combined with histological examination of excised lesions.


What is endometriosis? Upon reflection, this seemingly naive question is not easily answered. The traditional definition relies on histopathological criteria whereby ectopic endometrial stroma and glands are detected beyond the myometrium.

A narrow interpretation of this definition can easily lead to clinical paradoxes. For example, asymptomatic women with incidentally discovered microscopic foci of endometrial glandular and stromal cells would have, by definition, endometriosis. However, at present, there is no evidence supporting treatment of such a condition. Diagnosing endometriosis under such circumstances may be meaningless at best or possibly harmful when leading to unnecessary and potentially detrimental medical or surgical interventions.

In contrast, following the same strict criteria, symptomatic patients with atypical but clinically obvious disease with adhesions and multiple atypical lesions may be denied the diagnosis of endometriosis when, for example, histologic assessment of the lesions reveals only endometrial-like stroma, fibrosis, and inflammation but no obvious glands. Yet, it is apparent that such an inflexible approach to the definition of endometriosis fails to acknowledge our current understanding of the variability in lesions and their natural progression.[1]

These considerations underscore the complexity of issues surrounding the entire diagnostic process of this elusive disease. It is not surprising that the actual prevalence of endometriosis in the general population, estimated to range from 1 to 8%, is unknown.[2,3,4] Endometriosis is diagnosed far more frequently among women with infertility or pain, with prevalence ranging from 15 to 70%.[5,6]

This review discusses the available diagnostic tools, their advantages, and their limitations. Selectively, controversial findings are summarized. In the absence of easy and unequivocal tests, the ultimate goal of this article is to provide the clinician with a framework assisting in the process of diagnosing endometriosis. This process requires identification of patients at risk as well as a selective use of tests and their critical interpretation, preferably in the context of a complete laparoscopic and histologic assessment.


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