HYDROSALPINX

Cystic disease is common in the female pelvis. When evaluating a cystic adnexal mass, it is important to consider nonovarian disease processes that may mimic those of the ovaries, because a misdiagnosis can profoundly affect patient management [1].  Because the differ­ent types of cystic pelvic masses can have similar imaging features, radiology may be of limited diagnostic use [1]. It is important to understand the relationship of a mass with its anatomic location, identify normal ovaries at imaging, and relate im­aging findings to the patient’s clinical history to avoid misdiagnosis [1].

Most of the cystic masses have an ovarian origin, and they can range from simple follicles to ovarian carcinoma. Mimics of ovarian cystic masses include peritoneal inclusion cyst, paraovarian cyst, mucocele of the appendix, obstructed fallopian tube (eg, hydrosalpinx, pyosal­pinx, and hematosalpinx), uterine leiomyoma, adenomyosis, spinal meningeal cyst, unicornuate uterus, lymphocele, cystic degeneration of lymph nodes, lymphangioleiomyomatosis, hematoma, and abscess [1]. A pelvic mass has to be separate from the ovary in order to be considered a nonovarian mass. 

Clinical evaluation and laboratory testing are essential when a gynecologic condition is suspected to be the cause of acute pelvic pain. For the initial diagnostic imaging evaluation, ultrasonography (US) is the modality of choice [2].

The term hydrosalpinx is used to describe a dilated fallopian tube filled with fluid, pus, or blood, respectively. Blockage usually occurs at the fimbriated end of the fallopian tubes and is caused by adhesion from infectious or inflammatory processes [1]. The most common causes of hydrosalpinx are pelvic inflammatory disease and endometriosis; among women with these conditions, 8% develop hydrosalpinx [1].

Hydrosalpinx should be considered when one encounters an elongated cystic mass with a tubular shape that is not a vessel [3]. Indentations along opposite sides of the cystic mass, waist sign, is defined to be the most discriminating ultrasound feature of hydrosalpinx [4]. The sonographer operator should be careful not to mistake small tortuous veins with slow flow for a hydrosalpinx. The flow may be so slow that it is not detectable by Doppler techniques, and thus, one might assume that is a hydrosalpinx. Increasing the gray scale gain slightly and looking for movement of low level echoes in the lumen will help one recognize such veins with slow flow [5].

When US findings are equivocal, MR imaging is performed because its imaging fea­tures are identical to those seen at US [1].

Nondilated fallopian tubes are not usually seen on MR images unless they are outlined by pelvic fluid [6]. On MR images, the hydrosalpinx appears as a fluid- filled tubular structure that arises from the upper lateral margin of the uterine fundus and is separate from the ipsilateral ovary. A dilated fallopian tube folds upon itself to form a susage like C- or S-shaped cystic mass [7, 8].

On MR images, the signal intensity of the tubal fluid depends on the cause of the obstruction [6, 9]. On T1-weighted images, the signal intensity of the content of a dilated fallopian tube usually is that of simple fluid, but the tubal content may have signal intensity if it is hemorrhagic or proteinaceous [10]. On T2-weighted images, the cystic nature of the lesion with its incomplete internal septa, which have low signal intensity, may be seen [7].