A case of mesenteric cyst confused with ovarian endometrioma

Mesenteric cyst; Ovarian cyst; Pelvic; Endometrioma Received: 2012.5.25. Revised: 2012.7.10. Accepted: 2012.7.10. Corresponding author: Byung Chul Jee, MD, PhD Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 300 Gumi-ro, Bundang-gu, Seongnam 463-707, Korea Tel: +82-31-787-7254 Fax: +82-31-787-4054 E-mail: [email protected] This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright © 2012. Korean Society of Obstetrics and Gynecology Mesenteric cysts are rare disease and usually not considered in the differential diagnosis of pelvic cystic masses. Since most mes - enteric cysts are usually asymptomatic, they tend to be diagnosed incidentally during imaging tests or surgery [1]. In order to exclude malignant transformation and prevent further complications, large mesenteric cysts are recommended to be removed. Complete sur - gical resection is the treatment of choice with the excellent long‐ term prognosis [2]. Here we report a case of incidental mesenteric cyst, which was confused with ovarian endometrioma in preoperative assessment. Case Report A 15-year-old girl presented with history of irregular menstruation and an incidental pelvic cystic mass. The patient did not complain of dysmenorrhea, and denied sexual activity. The past medical his- tory was unremarkable. Laboratory tests including complete blood cell count and renal and liver function tests were all normal, except slightly increased alanine aminotransferase (ALT) (68 IU/L). The level of CA-125, CA- 19-9, and carcinoembryonic antigen were 20.6 IU/mL, 0.6 IU/mL, and 1.9 ng/mL, respectively (all were within normal range). In computed tomographic scan (CT), the cystic mass was 10.5 × 7.9 × 7.6 cm sized, unilocular shaped, and had relatively thick and prominent wall. It was supposed that the cyst doesn’t contain fat component or calcified materials. The origin of cystic mass was supposed to be her right ovary (Fig. 1). In addition, con- sidering its homogeneously hypoechoic cyst fluid and thick wall in ultrasonogram (Fig. 2), the cystic mass was thought to be right ovarian endometrioma. Based on the clinical impression of an ovarian endometrioma, laparoscopic approach was planned to perform right ovarian cys - tectomy. During the operation, it was confirmed that the origin of the cystic mass was not ovary, but mesentery (Fig. 3A). Both ova - ries were intact (Fig. 3B). To define and make delicate resection, surgical approach was CASE REPORT Korean J Obstet Gynecol 2012;55(9):683-686 http://dx.doi.org/10.5468/KJOG.2012.55.9.683 pISSN 2233-5188 · eISSN 2233-5196 WWW.KJOG.ORG684 KJOG Vol. 55, No. 9, 2012 changed into laparotomy. Examining bowel and mesentery, it was confirmed that the cystic mass was originated from mesentery which was 50 cm above ileocecal valve. It was surgically removed, clearly. Exploration of jejunum, ileum, cecum, and appendix was followed, and intactness was confirmed. The postoperative recov - ery was uneventful. 1. Histopathology Examination of the specimen showed a cyst filled with mucoid fluid. The cyst was lined by respiratory epithelium and focal squa - mous epithelium with glandular structure. Disoriented smooth muscle wall was also observed (Fig. 4). Combining these features, the cyst was consistent with enterogenous cyst, and the diagnosis of mesenteric cyst was made.

Mesenteric cysts are rare intra-abdominal disease, identified in about 1 out of 100,000 admissions in adults and 1 out of 20,000 in children [1]. Mesenteric cysts are known to occur in every part of mesentery, and the most common site is small bowel mesentery (ileum in 60%) and next is mesocolon (ascending colon in 40%). Although etiology and classifications are still controversial, mes - enteric cysts are clinically divided into 6 groups based on histo - pathological features: lymphatic origin; mesothelial origin; enteric origin; urogenital origin; mature cystic teratoma; nonpancreatic pseudocysts with traumatic or infectious origin [2]. Most mesenteric cysts are asymptomatic; therefore correct diagno- sis is difficult and incidentally diagnosed during imaging tests or surgery in many cases. Disease-related symptoms include abdomi - nal distension, pain, and/or palpable abdominal lumps [3]. Some patients can develop acute abdomen in case of complicated cysts, such as infection, hemorrhage, torsion, rupture, or bowel obstruc - Fig. 1. Computed tomography images showed a unilocular shaped cystic mass without fat and/or calcification. Its origin was supposed to be right ovary. Fig. 2. Trans-abdominal ultrasonogram showed homogeneously hy - poechoic feature of cystic mass. WWW.KJOG.ORG 685 Se Ik Kim, et al. A case of mesenteric cyst Fig. 4. Microphotographs. (A) Cyst wall on low grade magnification. (B-D) Lined by respiratory epithelium (black arrow and C) and focal squamous epi- thelium (gray arrow) with glandular structure (white arrow and D). Disoriented smooth muscle wall was also observed (star). (A, ×10; B-D, ×200, H&E stain). A B C D Fig. 3. Intra-operative findings. (A) The origin of cystic mass was mesentery. (B) Both ovaries were intact. A B WWW.KJOG.ORG686 KJOG Vol. 55, No. 9, 2012 tion [4-6], In diagnosis of mesenteric cysts, ultrasonography is the first-line diagnostic method [7]. Other image modalities including plain abdominal radiographs, gastrointestinal study using barium, CT, and magnetic resonance imaging (MRI) could be used in selected patients. Especially, CT and MRI could be more informative in measuring the exact extension and association with bowels [8]. However, if a mesenteric cyst locates within the pelvic cavity, as like our case, it may be misdiagnosed as an ovarian cyst [9]. It has been recommended that large mesenteric cysts are removed in order to exclude malignant transformation and prevent further complications [2]. The treatment of choice is complete surgical resection, and sometimes it may need bowel resection. A relation of the mesenteric cyst with the major abdominal vessels should be considered, and if needed, careful and accurate dissection should be performed. Furthermore, there is one case report documenting successful excision of the mesenteric cyst by laparoscopic opera - tions. Laparoscopy is regarded as a feasible method in selected patients [10]. Here we report a case of mesenteric cyst confused with ovarian endometrioma. The patient showed irregular menstruations only, and no other specific symptoms were noted. By the images, a pelvic cystic mass was founded incidentally. In practice, mesenteric cysts are usually not considered in the differential diagnosis of pelvic cystic masses. The more common considerations for pelvic cystic masses include ovarian cysts such as, endometrioma, der - moid cyst, and neoplasm. Thus we suggest that mesenteric cysts should also be considered in the differential diagnosis of pelvic cystic masses.

1. Vanek VW, Phillips AK. Retroperitoneal, mesenteric, and omental cysts. Arch Surg 1984;119:838-42. 2. de Perrot M, Bründler M, Tötsch M, Mentha G, Morel P . Mes- enteric cysts. Toward less confusion? Dig Surg 2000;17:323-8. 3. Egozi EI, Ricketts RR. Mesenteric and omental cysts in chil - dren. Am Surg 1997;63:287-90. 4. Fitoz S, Atasoy C, Ekim M, Yildiz S, Erden A, Aktug T. Torsion of a giant omental cyst mimicking ascites. J Clin Ultrasound 2007;35:85-7. 5. Ozdoğan M. Acute abdomen caused by a ruptured spon - taneously infected mesenteric cyst. Turk J Gastroenterol 2004;15:120-1. 6. Kim EJ, Lee SH, Ahn BK, Baek SU. Acute abdomen caused by an infected mesenteric cyst in the ascending colon: a case re - port. J Korean Soc Coloproctol 2011;27:153-6. 7. Mihmanli I, Erdogan N, Kurugoglu S, Aksoy SH, Korman U. Ra- diological workup in mesenteric cysts: insight of a case report. Clin Imaging 2001;25:47-9. 8. Okur H, Küçükaydin M, Ozokutan BH, Durak AC, Kazez A, Köse O. Mesenteric, omental, and retroperitoneal cysts in children. Eur J Surg 1997;163:673-7. 9. Long CY , Wang CL, Tsai EM. Incidental diagnosis of a mes - enteric cyst mimicking an ovarian cyst during laparoscopy. Taiwan J Obstet Gynecol 2011;50:388-9. 10. Tebala GD, Camperchioli I, Tognoni V, Noia M, Gaspari AL. Laparoscopic treatment of a huge mesenteric chylous cyst. JSLS 2010;14:436-8. 자궁내막종으로 오인한 장간막낭 1예 1서울대학교병원 산부인과, 2분당서울대학교병원 병리과, 3분당서울대학교병원 산부인과, 4서울대학교 의과대학 산부인과학교실 김세익1, 김영대1, 이혜승2, 지병철3,4 장간막낭은 드물고, 통상적으로 여성 골반강 낭성 종괴의 감별진단에 있어 고려되지 않고 있다. 본 저자들은 15세 여환의 골반강 낭성 종괴를 난소의 자궁내막종으로 오인한 장간막낭 1예를 경험하였기에 간단한 문헌고찰과 함께 보고하는 바이다. 중심단어: 장간막낭, 난소낭, 골반강, 자궁내막종