We report findings in four patients in whom focal areas of adenomyosis filled with saline during saline contrast sonohysterography (SCSH). Although seen directly on pathology and indirectly on hysterosalpingogram (HSG), a similar sonographic observation of the connection between the endometrial cavity and adenomyotic lesions has not been described.
In all four cases SCSH was performed within 10 days of the last menses, which is our routine practice. Following the sterile speculum exam, a silicone balloon HSG catheter (Cook Medical, Bloomington, IN, USA) was placed into the lower uterine segment or cervix. Sterile saline was then infused during real-time endovaginal sonographic imaging with a multifrequency, 8- or 10-MHz vaginal probe using Sequoia equipment (Acuson/Siemens, Mountain View, CA, USA).
Between July 1 2003 and December 31 2004, we performed 145 SCSH procedures and identified four cases of filling defects extending from the endometrial cavity into the myometrium at our center. We suspected adenomyosis in all patients prior to saline-infusion imaging based on subendometrial or myometrial cysts. The indication for SCSH in all four cases was abnormal vaginal bleeding and menorrhagia.
During SCSH saline-filled communications between the endometrial cavity and echogenic uterine lesions were identified (Figures 1c, 2b, 3b and 4b). In the regions of the saline-filled communications, preliminary transvaginal sonography had shown an echogenic mass, in contrast to a hypoechoic mass typical of a leiomyoma (Figures 1a, 2a, 3a and 4a).
A 53-year-old perimenopausal woman with dysmenorrhea was referred for SCSH. The patient was oligomenorrheic with menses every 2–4 months. Preliminary transvaginal sonography showed an echogenic region at the right fundus (Figure 1a), a subendometrial cyst on the left, posteriorly, and a thickened vascular endometrium suspicious for polyps (Figure 1b). A subendometrial cyst was seen in the left fundal uterus, consistent with the diagnosis of adenomyosis.
SCSH revealed three polyps and filling of the echogenic region at the right fundus (Figure 1c, Videoclip S1). A communication was clearly seen originating between two polyps and extending into the echogenic region, presumed to be an adenomyotic cavity.
A 43-year-old woman with intermenstrual bleeding and worsening menorrhagia was referred for pelvic sonography. The patient reported having had an endometrial polyp removed previously. Preliminary transvaginal sonography showed multiple small cysts within a circumscribed echogenic region within the right lateral myometrium (Figure 2a). This finding probably represents an adenomyoma or an area of focal adenomyosis. The endometrium appeared normal on unenhanced transvaginal sonography, but clinical suspicion of polyps was high. Therefore, SCSH was requested.
SCSH showed filling of the adenomyoma with direct communication to the endometrial cavity (Figure 2b, Videoclip S2). The endometrium was normal with a small adherent clot. Retrospective review of an HSG performed several years earlier showed multiple contrast-filled myometrial defects (Figure 2c).
A 42-year-old woman with dysmenorrhea and abnormal uterine bleeding, ultimately controlled with oral contraceptives, was referred for sonographic evaluation. Transvaginal sonography showed a thick, heterogeneous endometrium, suspicious for a polyp or leiomyoma. In addition, diffuse myometrial heterogeneity and multiple small myometrial cysts were seen, suspicious for adenomyosis (Figure 3a).
SCSH showed an intracavitary leiomyoma and a saline-filled channel entering the myometrium in the region of an echogenic lesion in the right posterior fundus (Figure 3b, Videoclip S3), presumed to be an adenomyotic cavity. Pathological examination after hysteroscopic resection confirmed that the intracavitary echogenic lesion was a leiomyoma. Pathological confirmation of adenomyosis was not possible.
A 46-year-old woman was referred for sonographic evaluation owing to abnormal vaginal bleeding and fibroids. Transvaginal sonography showed several small mixed-echogenicity and echogenic masses within the fundal myometrium (Figure 4a). During infusion of saline several of these echogenic areas filled with saline (Figure 4b, Videoclip S4). In addition, multiple echogenic, polypoid masses appeared to lie within or at the origin of the saline-filled cavities (Figure 4b). A small cystic right ovarian mass with solid mural nodule was noted. The patient underwent hysteroscopic resection of an ‘endometrial polyp’ but the hysteroscopist did not observe the fundal cavities described on SCSH. At the time of hysteroscopy, a laparoscopic resection of the right ovarian mass was performed. Pathology showed it to be a borderline mucinous cystadenocarcinoma. Thus, a hysterectomy and right oophorectomy were performed. Gross examination of the uterus showed multiple mural foci of adenomyosis, fleshy appearing polypoid masses and the cystic cavities observed with SCSH (Figure 4c). Microscopic examination of the adenomyotic cavities confirmed the presence of endometrial tissue (Figure 4d). Microscopic examination of the polypoid masses showed endometrial stromal nodules and leiomyomas.
We describe the finding on SCSH of saline extending into the myometrium in four cases of adenomyosis. In all four cases, saline was seen to fill a connection between the endometrium and focal homogeneously echogenic lesions within the myometrium. A similar finding was recently described in one case within a series comparing SCSH to magnetic resonance imaging in women with adenomyosis1.
Adenomyosis is a common condition resulting from invasion or displacement of the endometrium into the myometrium2, 3. On pathologic examination, endometrial glands are noted to be present within the myometrium, often in continuity with the endometrium2–4. In post-hysterectomy series, adenomyosis is identified in 10–70% of specimens2, 5–8. Clinically, adenomyosis is associated with dysmenorrhea and menometrorrhagia but is frequently asymptomatic7, 9. On HSG, evaginations of contrast into the myometrium are a reported sign of the presence of adenomyosis4, 10. Myometrial and sub-endometrial cysts may be demonstrated on transvaginal sonography as evidence of adenomyosis, with a sensitivity ranging from 65–81% and a specificity of 65–100%11–14.
Unlike most epithelial surfaces, the endometrium lacks a basement membrane to separate it from the myometrium2. Adenomyosis is an extension of the endometrium into the myometrium and may occur in various forms, including solid nodules, diffuse infiltration and small cysts. All have been observed with transvaginal sonography5, 13. Communications between the endometrial cavity and small cysts or outpouchings in the basal myometrium have previously been described with contrast HSG and are thought to represent evagination of contrast into the myometrium10. On HSG, these evaginations may appear to end in small ‘sacs’ or as a honeycomb pattern15, as seen in Case 2. It is likely that these small cystic spaces are inconsistently demonstrated since HSG only shows evaginations in 25% of specimens with pathologically proven adenomyosis4, 15. Specificity may also be low since false-positive examinations result when extravasation of contrast into the myometrium occurs, producing a similar appearance to the evaginations seen with adenomyosis15.
In pathological specimens, adenomyotic lesions are defined by the presence of a cystic space lined by endometrial tissue with surrounding stromal hyperplasia2. Although often not completely responsive to the variation in hormones of the menstrual cycle, the lining of adenomyotic lesions may be secretory16 and consequently echogenic, like the normal secretory endometrium. Similar echogenic lesions within the myometrium have previously been correlated with the ectopic endometrial tissue of adenomyosis in pathological specimens5, 17. The hyperechoic regions within the myometrium seen prior to saline infusion probably represent collapsed cavities lined by ectopic endometrial tissue. These lesions, which appear adjacent to the endometrium prior to saline infusion, might be misinterpreted as atypical leiomyomas on unenhanced sonography. In rare cases, intramural ectopic pregnancies have been identified within adenomyotic lesions18.
The finding of evaginations of contrast into the myometrium on HSG has been recognized as a sign of adenomyosis for many years. In Case 2, this finding was identified on an HSG many years earlier. The evaginations into the myometrium may represent the movement of contrast into adenomyotic cavities; however, they could also represent extravasation. The finding of a saline-filled communication into the myometrium is the sonographic correlate of evaginations of contrast on HSG.
Echogenic lesions that fill with fluid on sonohysterography are likely to represent adenomyotic lesions that communicate with the endometrial cavity. Based on the pathophysiology, it would be expected that, in some cases, SCSH is able to visualize the communication between the endometrium and adenomyosis.
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Videoclips S1 Case 1. (a) Prior to saline infusion, a parasagittal view shows an echogenic area (also shown in Figure 1a) in the myometrium curving around the endometrium. (b) During saline contrast sonohysterography, saline is seen extending from the endometrial cavity into the echogenic area seen in (a). This clip was obtained in the same view as that in (a). (c) During saline contrast sonohysterography, saline is seen to extend between two polyps in the endometrial cavity into the echogenic area in the myometrium. This clip was obtained in a slightly oblique plane similar to that in Figure 1c.
Videoclips S2 Case 2. (a) During saline contrast sonohysterography in a parasagittal view of the right cornua, multiple fluid-filled channels are visible in the myometrium. As the probe moves to the midline, these channels are seen to connect to the endometrial cavity. (b) During saline contrast sonohysterography, this clip starts in a sagittal view at the connection with the endometrial cavity and then moves to the right cornua where multiple fluid-filled channels are visible. The channels are noted to have an echogenic rim.
Videoclips S3 Case 3. (a) During saline contrast sonohysterography in a parasagittal view, a small saline-filled channel is visible extending from the endometrial cavity into the fundal myometrium distinctly separate from the uterine cornua. (b) During saline contrast sonohysterography in a parasagittal view, a small saline-filled channel is again visible extending from the endometrial cavity into the fundal myometrium.
Videoclips S4 Case 4. (a) During saline contrast sonohysterography in a sagittal view, large saline-filled channels are visible in the fundus. The endometrial cavity, labeled ‘EM cavity’ is deviated anteriorly. The adenomyoma is labeled and was confirmed on pathology. (b) During saline contrast sonohysterography in a sagittal view, large saline-filled channels are visible.