Two cases of ectopic ovary and one case of potential ectopic ovary

Abstract

Ectopic ovary is a rare gynecologic entity. A variety of synonymous terms such as ectopic ovary, supernumerary ovary, accessory ovary, and autoamputation of the ovary have been used to describe this condition. The etiology for ectopic ovary has not been elucidated, but several mechanisms have been proposed. They are categorized as either congenital (embryologically derived) or acquired. This report presents two cases of ectopic ovary resulting from different causes and one case of potential ectopic ovary.

Introduction

Ectopic ovary is a rare gynecologic entity. A variety of synonymous terms such as ectopic ovary, supernumerary ovary, accessory ovary, and autoamputation ofthe ovary have been used to describe this condition [1]. The etiology for ectopic ovary has not been elucidated, but several mechanisms have been proposed. They are categorized as either congenital (embryologically derived) or acquired. During the 16‐year period between 1994 and 2009, two cases of ectopic ovary and one case of potential ectopic ovary were found during laparoscopic ovarian surgery among 1,236 cases operated on at Fujita Health University Hospital. This report presents these two cases of ectopic ovary resulting from different causes and one case of potential ectopic ovary.

Case 1

A 25‐year‐old woman, gravida 0, para 0, presented to us with a complaint of infertility. The patient had no history of chronic pelvic pain. The CA 125 tumor marker level was within normal limits (15.1 U/mL), and the CA 19‐9 level was slightly elevated (55.7 U/mL). A magnetic resonance imaging (MRI) scan demonstrated a cystic mass measuring 56 × 40 × 52 mm behind the uterus and containing some solid component of ovarian cysts. An exploratory laparoscopy was performed, and three ovaries were found during the procedure. One was a cyst measuring 50 × 40 mm derived from the left eutopic ovary. Another mass represented the right ovary, which appeared to be eutopic. The third mass, representative of the third ovary, i.e., the accessory ovary, measured 20 × 20 mm and was found in the right infundibulopelvic ligament adjacent to the retroperitoneum. Both fallopian tubes were occluded (Fig. 1). We performed a left laparoscopic cystectomy and a biopsy of both of the right ovaries. The surgical specimen of the left‐sided mass weighed 50 g and was filled with fat containing hairs. A histologic examination revealed a typical mature cystic teratoma with adipose tissue and hair root sheaths. The biopsied specimen of both of the right ovaries showed normal ovarian stroma and germ follicles. Chromosomal evaluation showed a normal female karyotype (46, XX). Drip infusion pyelography (DIP) revealed no urinary tract abnormalities. Four years after the operation, the patient became pregnant after in vitro fertilization and delivered.

Figure 1.

Laparoscopic findings. The third mass representative of the third ovary, i.e., the accessory ovary, measured 20 × 20 mm and was found in the right infundibulopelvic ligament adjacent to the retroperitoneum

Case 2

A 34‐year‐old woman at 31 weeks’ gestation, gravida 1, para 1, presented to us with abdominal pain in the right lower quadrant. The patient was admitted and ultrasonography revealed a mass measuring 55 × 40 mm in the right adnexa. The pain subsided spontaneously after 7 days and she delivered a healthy girl weighing 3,343 g. Three months after delivery, an MRI scan showed a cystic mass behind the uterus measuring 55 × 40 × 44 mm and containing solid component which required investigation.

The tumor markers were within normal limits (CA 125 4.2 U/mL; CA 19‐9 7.1 U/mL). An exploratory laparoscopy was performed, and three ovaries were found during the procedure. The uterus, the left normal ovary, and an atrophic right ovary were identified. The atrophic right ovary was connected to the infundibulopelvic ligament (Fig. 2). There was also a pelvic mass separated from the atrophic right ovary (Fig. 2) which had no connection with the normal reproductive organs and was attached to the retroperitoneum. It was removed easily by blunt dissection. A histologic examination revealed a typical mature cystic teratoma with adipose tissue and hair root sheaths.

Figure 2.

Laparoscopic findings. The uterus, left normal ovary, and an atrophic right ovary were identified. The atrophic right ovary was connected to the infundibulopelvic ligament. Additionally, there was a pelvic mass separated from the atrophic right ovary

Case 3

A 31‐year‐old woman, gravida 0, para 0, presented with a complaint of irregular menstruation. The patient had no history of chronic pelvic pain. On pelvic examination, the uterus was normal in size, and a mobile tumor with an elastic hard consistency, was palpated behind the uterus. The CA 125 level was slightly elevated (68 U/mL). The CA 19‐9 level was within normal limits (12.1 U/mL). An MRI scan revealed a cystic mass behind the uterus measuring 127 × 100 × 116 mm. An exploratory laparoscopy was performed. The mass was connected to the normal left ovary via a thin connective tissue (Fig. 3). The connective tissue was only approximately 2 mm wide and was easily cut with a scalpel. A histologic examination of the mass showed an endometrial cyst with follicles.

Figure 3.

Laparoscopic findings. The width of the connective tissue (arrowhead) was only about 2 mm

Discussion

There has been some confusion with regard to the term “ectopic ovary,” and a variety of synonyms—such as ectopic ovary, supernumerary ovary, accessory ovary, and autoamputation of the ovary—have been used to describe this entity [1].

Supernumerary ovary and accessory ovary, in which the ovary is located somewhere other than the usual location of the normal ovary, are rare conditions that Winkle reported for the first time in 1890 [2]. There are many questions about the origin of this condition. True (embryologic) ectopic ovarian tissue is a rare gynecologic problem. Since Wharton's original description in 1959 [2], fewer than 40 cases have been reported in the literature [3]. This condition is estimated to occur in 1 in 29,000 to 1 in 700,000 gynecologic hospital admissions [4]. The classification of this condition is still debated [5, 6].

The relevant terms commonly used in the literature are the following:

1. Ectopic ovary This term was suggested by Lachman and Berman [6] to replace both the terms supernumerary and accessory ovary. It describes any ovarian tissue additional to the normal ovaries. Lachman proposed a new classification of abnormally located ovarian tissue. He suggested that ectopic ovary be further subclassified as follows: (a) post‐surgical implants; (b) post‐inflammatory implants; or (c) true (ectopic) ovarian tissue [6].

2. Supernumerary ovary This was defined as ovarian tissue entirely separate from the normally placed ovary. There is no ligamentous or direct connection with the ovaries, the broad ligament, the utero‐ovarian ligament or the infundibulopelvic ligament, and it arises from a separate primordial remnant [2].

3. Accessory ovary This was defined as excess ovarian tissue that is situated near the normally placed ovary. It may be connected with the normally placed ovary and it seems to have developed from it, possibly from tissue that was split from the embryonic ovary during its development [2].

4. Autoamputation of the ovary This was first reported by Sebastian et al. in 1973 [7]. The general consensus is that adnexal torsion leads to autoamputation [8].

Sometimes a supernumerary ovary and an accessory ovary are described as an ectopic ovary; however, the terms supernumerary ovary and accessory ovary can be easily misused. We agree with Lachman's proposal because cases considered to be supernumerary ovary or accessory ovary might be of acquired origin. Lachman found that almost 50% of the reported cases since 1959 were seen in patients with previous pelvic surgery [6].

Case 1 may be a good example of an accessory ovary. This ectopic right ovary was connected to the right infundibulopelvic ligament. The biopsy of both right ovaries showed normal ovarian stroma and germ follicles. An accessory ovary may occur in two ways. First, according to embryonic theories, an accessory ovary is believed to result from the abnormal separation of a small portion of the developing and migrating ovarian primordium [9, 10]. Second, an accessory ovary can occur from acquired conditions such as inflammation and surgery. We believe that Case 1 is truly embryologically ectopic because the patient had no history of chronic pelvic pain or previous surgical procedures. Moreover, the bilateral defects of the tubes and the fact that the ectopic ovary was attached to the infundibulopelvic ligament suggest that this lesion had a congenital origin. Case 2 may be a good example of an ectopic ovary of acquired origin. Case 2 illustrates the autoamputation of an ovary with a cystic teratoma and subsequent vascularization, which indicates a possible acquired mechanism for formation of an ectopic ovary. Torsion of the pedicle is known to be the most frequent complication of ovarian teratomas. The torsion interferes with the blood supply and causes necrosis of the tumor, and on rare occasions may induce subsequent autoamputation. Therefore, a dermoid cyst may have an inherent potential to develop into an ectopic ovary. According to the literature [1, 5, 11, 12], the omentum is one of the common sites for an ectopic ovary. In this case, the mass may have received a blood supply from other tissue after autoamputation of the dermoid cyst. The Lachman classification of this case would be ectopic ovary, post‐inflammatory implant. Case 3 is considered to be a good example of potential ectopic ovary. We assume that a lobulated ovary such as seen in Case 3 may lead to ectopic ovary when the lobulated part is twisted. Figure 3 shows the connective tissue between the normal ovary and the tumor. The connective tissue (arrowhead) was easily cut with a scalpel. As the connective tissue was only about 2 mm wide it is possible that a lobulated ovary may cause the formation of an ectopic ovary when the lobulated part is torn off the normal ovary. Thus, a lobulated ovary is a possible source of an ectopic ovary. Most frequently, the tumor will be necrotic when the lobulated tumor is torn off the normal ovary; however, some tumors may receive a blood supply from other tissue.

In summary, we have discussed two cases of ectopic ovary stemming from different origins and one case of potential ectopic ovary. All these cases were found incidentally at laparoscopic surgery as pre‐operative diagnoses of these conditions are difficult. Our retrospective review of these three cases suggests that ectopic ovary may be congenital or of acquired origin.