IntroductionMature cystic teratoma (MCT) of the ovary, as a synonym for the ovarian dermoid cyst, is a benign germ cell tumor. The words “teratoma” and “dermoid” were first described by Leblanc in 1831[1]. The incidence of MCT is 10–20 % of all ovarian tumors. It shows the highest incidence in reproductive age women (range 20 to 40 years) [2,3]. It is a slow growing tumor, and the estimated increasing rate is 1.8 cm per year [4]. Long term recurrence rate is less than 5 % after fertility sparing surgery making it a good option for reproductive age group [5].CaseA 17-year-old girl presented with a history of palpable lump in lower abdomen since two years, gradually increasing in size. Initially she consulted a local practitioner and was told to have an ovarian cyst and advised surgery. However, the patient did not take any treatment for two years. Two months ago, she had an episode of acute abdomen. Diagnostic work-up was done at a tertiary center: ascitic tapping was negative for tuberculosis and malignancy; PET scan was suggestive of ovarian malignancy. She underwent laparotomy but the pelvic mass could not be excised due to dense adhesions with bowel and the abdomen was closed and patient referred to our institute.On examination, she had a 15x15 cm abdomino-pelvic mass, firm to hard in consistency, non-tender, with irregular margins and restricted mobility. Serum tumour markers were as follows: alpha feto-protein-2.6 ng/mL (10-20 ng/mL), beta-hCG-1.2 mIU/ml (<5.0 mIU/ml), lactate dehydrogenase- 182 U/L (140-280 U/L), CA125-16.5 U/mL (<35.0 U/mL), carcinoembryonic antigen-12.2 ng/mL (<2.5 ng/mL), CA19.9- 35 U/mL (<37.0 U/mL). Ultrasonography showed a 10x10 cm hypoechoic lesion arising from the left ovary with internal hyperechoic septae and calcifications. On CECT, a 10x7x10 cm solid-cystic lesion which was FDG-avid on PET scan was seen arising from left ovary with multiple septae and calcifications.With a clinical diagnosis of immature teratoma, she was taken for a staging laparotomy. There was a 15x15 cm irregular cystic mass arising from the left ovary which was densely adherent to anterior abdominal wall, omentum and small bowel. There was no ascites, nor were there any peritoneal deposits. On cut section, the multilocular cyst was found to contain sebaceous material, hair and well-formed bowel-like structures (Fig. 1). Left salpingo-oophorectomy and omental biopsy were done and she made an uneventful recovery.Histopathology confirmed a left ovarian mature teratoma with derivatives from all three germinal layers including skin, bone, respiratory epithelium, intestinal epithelium, nerve bundles, skeletal muscle and glial tissue. Immature elements were absent (Fig. 2, A-F).DiscussionMCT contains components originating from three germ cell layers (ectoderm, mesoderm, and endoderm) with varying ratios of skin, neural, teeth, cartilage, respiratory and intestinal epithelium [3]. They include elements of ectodermal origin in 99–100%, mesodermal origin in 73–93%, and endodermal origin in 32–72% [6-8]. About 7–13 % of MCT cases include intestinal epithelium [7], however, there are only a few cases of ovarian MCT containing complete intestinal structures [9,10].Woodfield et al first reported almost complete development of the gastrointestinal tract in a benign cystic teratoma first containing esophagus to colon [11]. Subsequently only four cases of MCT containing well oriented complete intestinal structure have been reported in the literature and these are described in table 1. In most of them the tumor size was less than 10 cm which in our case was also 10 cm. CEA can be an important marker for predicting presence of intestinal epithelium and to be vigilant for malignant intestinal cancers which was also raised in our case [12,13]. Well differentiated mature neuronal component showed FDG activity misleading the diagnosis as also found in our case [14]. In view of low rate of long term recurrence, fertility sparing surgery was done in the current case as well.ConclusionOccurrence of formed bowel inside a mature cystic teratoma is very rare. Significance of this finding is that the colonic epithelium may be the origin of adenocarcinoma. In cases where the mature cystic teratoma is densely adherent to bowel and has been dissected out after adhesiolysis; the cut section of specimen showing bowel can be alarming to the surgeons.Author’s contributions: All authors contributed to the study conception and design.The first draft of the manuscript was written by SK and all authors reviewed and edited the previous versions of the manuscript. All authors read and approved the final manuscriptConsent for publication: Obtained from the patient’s fatherFunding: Not applicableAvailability of data and material: Not applicableConflicts of interest: There is no conflict of interests among the authorsKey Clinical MessageAbout 7–13 % cases of mature cystic teratoma contain intestinal epithelium but there are only a few reported cases containing complete intestinal structure. We discuss here the case of a 17 year old girl with the above finding and its management.Keywords: bowel, dermoid cyst, intestinal epithelium, mature teratoma, ovaryReferences1. Kim MJ, Kim NY, Lee DY, Yoon BK, Choi D. Clinical characteristics of ovarian teratoma: age-focused retrospective analysis of 580 cases. Am J Obstet Gynecol. 2011;205(1):322. Alotaibi MO, Navarro OM. Imaging of ovarian teratomas in children: a 9-year review. Can Assoc Radiol J. 2010;61(1):23–8.3. Caspi B, Appelman Z, Rabinerson D, Zalel Y, Tulandi T, Shoham Z. The growth pattern of ovarian dermoid cysts: a prospective study in premenopausal and postmenopausal women. Fertil Steril. 1997;68(3):501–5.4. Chang CF, Lin CK. A case of recurrent, bilateral ovarian mature teratoma in a young woman. BMC Womens Health. 2014;14:57–60.5. Templeman CL, Fallat ME, Lam AM, Perlman SE Hertweck SP, O’Connor DM. Managing mature cystic teratomas of the ovary. Obstet Gynecol Surv. 2000;55(12):738–45.6. Marcial-Rojas RA, Medina R. Cystic teratomas of the ovary. A clinical and pathological analysis of two hundred sixty-eight tumors. Arch Pathol. 1958;66:577–5897. Caruso PA, Marsh MR, Minkowitz S, et al. An intense clinicopathologic study of 305 teratomas of the ovary. Cancer. 1971;27:343–348.8. Blackwell WJ, Dockerty MB, Masson JC, et al. Dermoid cysts of the ovary. Their clinical and pathologic significance. Am J Obstet Gynecol. 1946;51:151–172.9. Fujiwara K, Ginzan S, Silverberg SG. Mature cystic teratomas of the ovary with intestinal wall structures harboring intestinal type epithelial neoplasms. Gynecol Oncol. 1995;56:97–101.10. Tang P, Soukkary S, Kahn E. Mature cystic teratoma of the ovary associated with complete colonic wall and mucinous cystadenoma. Ann Clini Lab Sci. 2003;33(4):465–70.11. Woodfield B, Kate DA, Cantrell CJ, et al: A benign cystic teratoma with gastrointestinal tract development. Am J Clin Pathol 1985;83 :236–240.12. Takao M, Yoshino Y, Taguchi A, Uno M, Okada S, Kino N, et al. A case of mature cystic teratoma with intestinal structures harboring intestinal-type low-grade mucinous neoplasm. Int Canc Conf J. 2018; 7(2):59-6413. Makihara N, Ebina Y, Yamasaki Y, et al. Preoperative prediction of malignant transformation arising in a mature cystic teratoma of the ovary. J Minm Invasive Gynecol. 2014;30:112–116.14. Yokoyama T, Takehara K, Yamamoto Y, Okame S, Shiroyama Y, Yokoyama T, Nogawa T, Sugawara Y. The usefulness of 18F-FDG-PET/CT in discriminating benign from malignant ovarian teratomas. Int J Clin Oncol. 2015 Oct;20(5):960-6. doi: 10.1007/s10147-015-0800-0. Epub 2015 Feb 15. PMID: 25681878.15. Nelson, D.B., Hoffman, B.L., Lemeshev, Y. et al. Avoiding the bowel: a report of a mature cystic teratoma displaying fully developed intestinal tissue protruding from an ovarian tumor. Gynecol Surg 8, 223–225 (2011).Table 1: Case reports with intact intestinal segment associated with Mature cystic teratoma
