Echogenic Foci in the Ovary: Are They Predictive of Endometriosis?

Abstract

The diagnosis of endometriosis usually necessitates an operative procedure. Although ultrasonographic findings can be predictive of endometriomas, the question is whether in the presence of normal ovaries, other visual clues are available to enable the diagnosis of endometriosis. This study from the Mayo Clinic examined the presence of echogenic foci visible sonographically in the ovaries of some women. Foci were described as being 1 to 3 mm long, with no distal acoustic shadowing. The origin of these foci is hypothesized to be calcifications, hemosiderin, or specular reflectors from the walls of tiny follicles too small to be resolved. Such foci can be observed in the walls of 35% of endometriomas. However, are they seen in as many as 77% of women with endometriosis? Can their presence be predictive of disease? One hundred forty-six women, 70 with endometriosis and 76 without endometriosis, were evaluated. Ultrasound imaging was performed less than 2 months before surgery in 71% of patients. Patients with echogenic foci were slightly older (median age, 44.1 years vs 39.5 years). Echogenic foci were more commonly observed in ovaries of women with endometriosis (47% vs 28%; p = .02), with bilateral echogenic foci in 17 study patients and 8 control patients. However, the association between echogenic foci in the ovaries and endometriosis was present only when patients with multiple echogenic foci in their ovaries were compared with patients without echogenic foci in either ovary (p = .01). When patients with an endometrioma or other ovarian mass evident at sonography were excluded (i.e., evaluating only women with normal ovaries), there was a trend toward echogenic foci being associated with endometriosis; however, it was not statistically significant: 8 of 23 women with endometriosis (35%) vs 10 of 42 women without endometriosis (24%) (p = .34). Multiple echogenic foci, as apposed to 1 focus, or both ovaries, as opposed to 1 ovary, also were not statistically significant. At sonography, 32 ovaries seemed to demonstrate a mass typical of an endometrioma, 22 of which exhibited echogenic foci in the same ovary. At pathologic analysis, 28 of 32 masses were confirmed as endometriomas, only 21 of which had echogenic foci, and these were all located in the wall of the endometrioma. In addition, echogenic foci were more common in masses with a sonographic appearance typical of an endometrioma (22 of 32 [69%]) than in other adnexal masses (18 of 66 [27%]) (p = .001). As the authors note, the frequency, cause, and importance of sonographically detected echogenic foci in the ovaries remains unresolved. The group found echogenic foci in the ovaries of 35% of women. However, these women all had a history of pelvic surgery and, thus, were not a typical population. Incidences from 49% of women and 37% of ovaries to 60% of postmenopausal ovaries have been reported. In conclusion, the results of this study indicate that detection of echogenic foci is only moderately sensitive for endometriosis because these foci occurred in only 46% (33 of 70) of women with endometriosis and in 28% (21 of 76) of women without endometriosis (p = .02). Although echogenic foci were more common in ovaries of women with endometriomas than in ovaries of women without endometriomas, the association was significant only when there was a concomitant ipsilateral endometrioma. Echogenic foci are not predictive of endometriosis in women with otherwise sonographically normal ovaries. Laparoscopy is still essential for the diagnosis of endometriosis.