Inguinal endometriosis in a patient without a previous history of gynecologic surgery

Endometriosis is defined as growth of endometrial tissue outside the uterine cavity. This condition has a prevalence of 10% to 20% in women of reproductive age, with occur - rence mainly in the pelvic organs, particularly the ovaries, pouch of Douglas, and pelvic peritoneum [1]. Additionally, endometriosis can also occur in extrapelvic organs such as the gastrointestinal and urinary tracts, and the thoracic cavity, umbilicus, abdominal wall incisions, central nervous system, bone, episiotomy scars, and abdominal wall, and rarely, in the inguinal canal [2,3]. Candiani et al. [4] reviewed 958 patients who had endometriosis and reported that only 0.6% of pa - tients had inguinal endometriosis. Due to its rarity, inguinal endometriosis is often misdiagnosed or overlooked. Its most common symptoms are palpable inguinal mass, often accom- panied by change of mass size and inguinal pain related to menstrual cycle [2,4]. Most cases of inguinal endometriosis are associated with previous surgery in the uterine cavity [2,5]. In Korea, only 6 patients in 4 case reports have been reported to have inguinal endometriosis [6-9]. We report an additional case of right inguinal endometriosis in a patient with no pre- vious history of gynecologic surgery; this patient was treated by a general surgeon using a wide excision. Case report A 40-year-old nulliparous woman presented with a pain - ful mass in her right inguinal area. The mass had grown for 2 years and had occasionally been tender, especially during menstrual cycles. The patient had no specific medical or surgi- cal history. She experienced regular menstruation at 30-day intervals and experienced menorrhagia. Her menstruation period lasted 7 days. Physical examination revealed a non-erythematous swol - len and tender mass measuring approximately 2×2 cm located lateral and superior to the pubic tubercle. The size Inguinal endometriosis in a patient without a previous history of gynecologic surgery Da Hee Kim 1 , Min Jung Kim 1 , Mi-La Kim 1 , Jong Taek Park 1 , Ji Hyun Lee 2 Departments of 1 Obstetrics and Gynecology, 2 General Surgery, CHA Gangnam Medical Center, CHA University, Seoul, Korea Endometriosis, defined as growth of endometrial stroma and glands outside the uterine cavity, is a chronic and recurrent disease that affects patients’ quality of life. Ectopic endometrial tissue can proliferate at any location in the body, but the pelvic organs and peritoneum are the most frequent implantation sites. Among extrapelvic endometriosis, inguinal endometriosis is a very rare gynecologic condition usually associated with previous pelvic surgery. Endometriosis should be preoperatively distinguished from other inguinal masses using computed tomography, magnetic resonance imaging, or ultrasonography. Here, we report a case of right inguinal endometriosis in a patient with no previous history of gynecologic surgery; in addition, we have provided a brief review of relevant literature.

Endometriosis; Inguinal; Round ligament; Ultrasonography Case Report Obstet Gynecol Sci 2014;57(2):172-175 http://dx.doi.org/10.5468/ogs.2014.57.2.172 pISSN 2287-8572 · eISSN 2287-8580 www.ogscience.org 173 Da Hee Kim, et al. Inguinal endometriosis without gynecologic surgery and position of the mass remained unchanged, even when the patient coughed or changed positions. The patient also reported intermittent vaginal spotting, for which she had undergone simultaneous transvaginal and inguinal ultraso - nography. The transvaginal ultrasonography revealed two left ovarian cysts measuring 1.0 cm that seemed to be endometrioma or hemorrhagic corpus luteal cysts (Fig. 1A, B). Inguinal ultra - sonography showed an ill-defined hypoechoic lesion (size, 1.1×1.2 cm) in the right pubic area, with increased vascular- ity (Fig. 1C, D). She underwent repeated inguinal ultrasonog- raphy during her menstrual period. She felt tenderness and swelling of the lesion, but there was no change of mass size on inguinal ultrasonography. After being informed about the presence of hemangioma or arteriovenous malformation, the patient opted for surgical excision of the inguinal mass. An oblique skin incision was performed along the line running from the pubic tubercle to the anterior superior iliac spine, at the superior margin of the inguinal ligament. After identification of the femoral vessels, the hard mass was widely excised to include a part of the round ligament. Chocolate-colored fluid was drained from the hard cystic mass during the procedure, and the mass was connected with the intraperitoneal round ligament at the inguinal canal. The inguinal canal was opened and the extraperito - neal portion of the round ligament was resected by gentle traction and then cutting at the level of the internal ingui - nal ring. The proximal stump was fixed to the surrounding fibrous structure of the inguinal canal. Histological examina- tion showed a cuff of endometrial stroma surrounding the endometrial glands with hemorrhaging from smooth muscle and fibrous tissues (Fig. 2). After 2 months of the surgery, the patient’s pain completely resolved and she was fully recovered without complications. Considering the possibility of recurrence of the inguinal endometriosis and progression of the ovarian endometrioma, we recommended her to use the oral contraceptives and planned regular follow-up. Fig. 1. Transvaginal ultrasonographic findings of the adnexa and inguinal mass. (A) Right ovary was grossly normal. Left ovary showed two low-echoic cysts. (B) Doppler transvaginal ultrasonographic findings of the left ovarian cyst. The longitudinal and transverse view showed two low-echoic cysts of 1.0 cm size. (C) Inguinal ultrasonographic findings of the inguinal mass. The longitudinal and transverse views show an ill-defined hypoechoic lesion (size, 1.1×1.2 cm). (D) On Doppler ultrasonographic findings showed increased vascularity of the mass in the right pubic area. A C B Right Left D www.ogscience.org174 Vol. 57, No. 2, 2014

Inguinal endometriosis is a rare clinical condition occurring in only 0.6% of women [4]. Patients with inguinal endometriosis complain of inguinal mass and pain, in particular, acute pain during menstrual cycles [2,4]. Inguinal endometriosis is usually concomitant with pelvic endometriosis [4,10], suggesting a similar pathogenesis for both conditions. Clausen and Nielsen [11] suggested several possible theories, including implantation of endometrial tis - sue by transtubal regurgitation during the menstrual cycle, metastasis via venous or lymphatic channels, congenital hor- monal activation of embryonal cells from the Müllerian duct, metaplasia of mesothelial cells, and direct extension from the pelvis along the round ligament. In the case of inguinal endo- metriosis, the right side is more commonly affected than the left, and is often associated with inguinal hernia, and its oc - currence on both sides is rare [4,5,8,12]. The reasons for the right-predominance are unclear. Sun et al. [13] proposed two different theories: 1) the sigmoid colon protects the left ingui- nal canal and 2) endometrial cells remain on the right side for a longer period due to clockwise flow of intraperitoneal fluid. Our patient exhibited right-sided inguinal endometriosis, the most common presentation. Differential diagnosis is essential in cases of suspected inguinal mass. Causes of inguinal mass include hernia, lymphadenopathy, neuroma, abscess, hydroceles, hematoma, lymphoma, lipoma, sarcoma, subcutaneous cysts, and cancer [9]. Computed tomography (CT), magnetic resonance imaging (MRI), and ultrasonography are useful diagnostic tools. The CT appearance of inguinal endometriosis is often not specific [9,14], presenting as either solid, cystic, or complex (i.e., the same density as muscle). MRI is more accurate than CT . Gaeta et al. [14] described two MRI patterns for inguinal endome - triosis. Type I pattern consist of cystic hyperintense lesions, on both T1- and T2-weighted images. Type 2 lesions have solid components, showing a high signal intensity on T1-weighted images and either hypointensity or moderate hyperintensity on T2-weighted images with some “shading signs” for cystic lesions [14]. The ultrasonographic findings of inguinal endo- metriosis are variable. Round or oval cystic masses, represent- ing intracystic bleeding associated with menstruation are found in most cases, although homogeneously hypoechoic solid or combined cystic and solid masses have also been de- scribed [9]. The differential diagnosis of cystic masses includes inguinal hernia and hydrocele, and solid masses should be differentiated from sarcoma, lymphoma, hematoma, and ab- scesses. Since no available diagnostic imaging tools are spe- cific for inguinal endometriosis, differential diagnosis based on imaging results must be combined with a careful review of the history of cyclic menstrual pain associated with inguinal mass [9,14]. Fine-needle aspiration cytology allows accurate preoperative diagnosis and exclusion of malignancy and can be useful in selected cases [9,15]. Patients with inguinal endometriosis may have a history of gynecologic or abdominal surgery [2,5,10]. In the absence Fig. 2. Microscopic findings of the excised specimen of inguinal endometriosis. The endometrial glands are surrounded by a cuff of endo - metrial stroma, with hemorrhage involving smooth muscle and fibrous tissue in the round ligament. (A) H&E, ×40; (B) H&E, ×200. A B www.ogscience.org 175 Da Hee Kim, et al. Inguinal endometriosis without gynecologic surgery of a surgical history, however, inguinal endometriosis may be misdiagnosed as another groin diseases and managed by a general surgeon. In our case, the patient had no history of previous surgery, and ultrasonograph showed an ill-defined hypoechoic lesion with increased vascularity. We made a presumptive diagnosis of hemangioma or arteriovenous mal- formation and referred the patient to a general surgeon for treatment. If inguinal endometriosis been correctly diagnosed preoperatively, the patient could have undergone laparoscopic surgery rather than wide excision of the inguinal area. It is therefore important to consider inguinal endometriosis in the differential diagnosis in patients with inguinal mass, even if there is no history of gynecologic or abdominal surgery. The treatment for inguinal endometriosis is radical surgical excision of the lesion and the extraperitoneal round ligament [12]. In patients with concomitant inguinal endometriosis and pelvic endometriosis, which occurs in most cases, either laparoscopy or laparotomy can be employed for the exci - sion. However, no such associated disease is present, neither laparoscopy nor laparotomy is necessary [11,13]. Hormonal therapy is recommended in addition to surgery, as it plays an important role in preventing recurrence of endometriosis [7]. In conclusion, inguinal endometriosis is a very rare disease compared to pelvic endometriosis. Nonetheless, extrapelvic endometriosis should be considered in the differential diagno- sis in cases in which women are of reproductive age and pres- ent with an inguinal mass, even in those without a history of gynecologic surgery. Pain associated with the menstrual cycle and characteristic ultrasonographic findings also are helpful for diagnosis. Conflict of interest No potential conflict of interest relevant to this article was reported.

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