{"paper_id":"18bc2610-4152-4192-a3b8-30c0d3c944c1","body_text":"C A S E R E P O R T Open Access\nExtra-uterine low grade endometrioid\nstromal sarcoma arising from ovarian\nendometriosis: a case report and review of\nthe literature\nBoubacar Efared 1,2* , Ibrahim S. Sidibé 1, Fatimazahra Erregad 1, Nawal Hammas 1,3, Laila Chbani 1,3 and\nHinde El Fatemi 1,3\nAbstract\nBackground: Endometrial stromal sarcoma (ESS) is a rare neoplasm accounting for only 0.2% of female genital tract\ntumors. The primary extra-uterine location of ESS is an extremely uncommon occurrence.\nCase presentation: We present a case of a 64-year-old woman presenting with abdominopelvic and bilateral\novarian tumors with misleading clinical presentation and diagnostic challenge. The histopathological examination\nof the resected specimens disclosed the diagnosis of primary extra-uterine ESS arising from ovarian endometriosis.\nAdjuvant therapy with an aromatase inhibitor drug was prescribed for the patient, and she is still alive with no\nevidence of disease 7 months after surgery.\nConclusion: The awareness of the potential extra-uterine location of ESS should lead to correct diagnosis as this\ntumor has histopathological features and clinical behavior similar to its uterine counterpart.\nKeywords: Endometrioid stromal sarcoma, Uterus, Ovary, Endometriosis\nBackground\nEndometrial stromal sarcoma (ESS) is a rare distinct patho-\nlogic entity accounting for only 0.2% of female genital tract\ntumors [1] .T h et u m o ri sc o m m o n l yf o u n di nt h eu t e r u s ,\nhowever it can be located elsewhere posing significant diag-\nnostic challenges [ 1–3]. The extra-uterine ESS (EESS) is\nsupposed to derive from endometriosis, as most reported\ncases of EESS were associated with foci of endometriosis [2,\n4]. Ovaries are common site of EESS, although many or-\ngans could be involved, such as peritoneum, vagina, colon,\nsmall bowel, stomach, lung [ 1, 5–9]. In these extra-uterine\nlocations, clinical symptoms a re widely variable and mis-\ndiagnoses are very common [1]. To claim the diagnosis of a\nprimary EESS, the uterus must be free of tumor as it consti-\ntutes the main primary site of ESS [ 2]. Most reported cases\nof ovarian ESS were of low grade type, however high grade\novarian ESS have been reported [10].\nWe report herein a case of a 64-year-old wowan pre-\nsenting with abdominopelvic and bilateral ovarian tu-\nmors diagnosed histologically as low grade ESS arising\nfrom ovarian endometriosis.\nCase presentation\nIn November 2017 a 64-year-old wowan presented to our\nhospital with abdominopelvic and bilateral ovarian tumors\nrecently discovered on magnetic resonance imaging\n(MRI). The physical examination was quite normal, the\npatient did not report metrorrhagia or other gynecologic\nsymptoms. The patient did not report any hormone re-\nplacement therapy. Her medical history revealed that she\nhad undergone surgery at an outside hospital for a 18 cm\nabdominopelvic mass 5 months ago (in June 2017). The\npatient was also treated for blood hypertension since\n2004. At that time, the initial histopathological diagnosis\nwas extra-uterine low grade endometrioid stromal\n* Correspondence: befared2013@gmail.com\n1Department of pathology, Hassan II University Hospital, Fès, Morocco\n2Department of pathology, FSS, UAM, Niamey, Niger\nFull list of author information is available at the end of the article\n© The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0\nInternational License ( http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and\nreproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to\nthe Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver\n(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.\nEfared et al. Gynecologic Oncology Research and Practice             (2019) 6:2 \nhttps://doi.org/10.1186/s40661-019-0067-7\n\nsarcoma (EESS), and the performed endometrial biopsy\nshowed atrophic endometrium with no evidence of tumor.\nThen, the case has been reviewed by 2 other additional pa-\nthologists in different centers, their diagnoses were\nsex-cord stromal tumor (fibroma) and smooth muscle\ntumor respectively. Five months later (November 2017),\nMRI was performed and revealed 2 latero-uterine (ovar-\nian) solido-cystic tumors measuring 60 × 53 mm (left) and\n47 × 40 mm (right), along with 2 pelvic masses (located in\nthe recto-vaginal fascia and in the vicinity of the uterine\ncervix). The uterus was radiologically normal. Then, again\nthe patient underwent subtotal hysterectomy with bilateral\nsalpingo-oophorectomy as well as resection of the 2 pelvic\nmasses and random biopsies of the abdominal wall.\nThe macroscopic examination of the resected speci-\nmens was as follow:\n– Right ovary: a well circumscribed 5 × 4 cm solido-\ncystic tumor, the cut surface showed a vaguely lobu-\nlated whitish tumor with cystic areas filled of pasty\nyellowish material (Fig. 1a).\n– Left ovary: a 6 × 4 cm whitish lobulated tumor with\na cystic areas containing a chocolate-like\nhemorrhagic material (Fig. 1b).\n– The 2 pelvic masses: measured 2 × 3 cm and 7 × 8\ncm, with solid architecture and pale color.\n– Hysterectomy: measured 4 × 5 cm, with no evidence\nof macroscopic lesion.\nThe histological examination of the right adnexal le-\nsion showed ovarian parenchyma largely occupied by a\ndiffuse tumoral proliferation composed of round to spin-\ndle cells with oval hyperchromatic nuclei and moderate\ncytological atypia, the mitotic figures were scant (3 mi-\ntoses/10 high-power fields). The tumor stroma showed\nnumerous juxtaposed small arterioles with sometimes\nhyalinazed walls. Tumor cells surrounded these vessels\nin a striking whorling pattern (Fig. 2a and b). In some\nareas of the tumor (especially cystic areas), foci of regu-\nlar dilated endometrioid glands were found intimately\nembedded in the tumor (Fig. 3a). At the periphery of the\novarian parenchyma, a tongue-like protrusion in the ves-\nsel walls was observed (Fig. 3b). The histological exam-\nination of the other specimens were identical to the\nright adnexal tumor, however endometrioid glands were\nnot noticed. These histomorphologic characteristics\nwere reminiscent of the proliferative endometrial stroma\nand the diagnosis of a low grade EESS arising from right\novarian endometriosis was suggested. The examination\nof the uterus was normal with no evidence of any histo-\nlogical lesion.\nAt immunohistochemistry, tumor cells were positive\nfor CD 10 and for estrogen and progesterone receptors\n(ER, PR) (Fig. 4a and b), with focal positive staining with\ndesmin. They were negative for smooth muscle actin\n(SMA) (Fig. 5), inhibin, calretinin and synaptophysin.\nThe diagnosis of disseminated low grade EESS arising\nfrom the right ovarian endometriosis was disclosed. Ad-\njuvant therapy with an aromatase inhibitor drug (letro-\nzole) was performed, and the patient is still alive with no\nevidence of disease 7 months after surgery.\nDiscussion\nExtra-uterine endometrioid stromal sarcoma (EESS) is an\nextremely uncommon entity as the current literature of-\nfers only some case reports and short series [ 1, 2, 4, 10].\nIn 2013, Masand et al. reported the largest series of EESS\nwith 63 cases, ovarian involvement was found in 25 pa-\ntients [1]. Ovaries are the most common site of EESS, the\npatients’ age ranged from 34 to 76 years with a median age\nFig. 1 Macroscopic aspects of the ovarian tumors. a (right ovary): a well circumscribed solido-cystic tumor, the cut surface showed a vaguely\nlobulated whitish tumor with cystic areas filled of pasty yellowish material. b (left ovary): a whitish lobulated tumor with a cystic areas containing\na chocolate-like hemorrhagic material\nEfared et al. Gynecologic Oncology Research and Practice             (2019) 6:2 Page 2 of 7\n\naround 50 years [ 2, 10]. Foci of endometriosis are fre-\nquently found embedded within EESS and these tumors\nare thought to arise from endometriosis [ 1, 4]. The clinical\npresentation of EESS is not specific, it is often related to\nthe tumor location and size. Reported cases of patients\nwith ovarian ESS presented with wide clinical symptoms,\nfrom asymptomatic to abdominal distension [ 2, 10].\nMostly, ovarian ESS was diagnosed in advanced stages\nwith tumor extension beyond the ovaries, especially in the\npelvis or abdomen [ 2, 4, 10]. Our current case typically il-\nlustrates this clinical feature as previously reported in the\nliterature; she presented initially with a huge abdomino-\npelvic mass, then 5 months later with radiologically dis-\ncovered ovarian and pelvic tumors. However, because of\nthe initial absence of ovarian tumors, one could speculate\nthat our patient had perhaps abdominopelvic foci of endo-\nmetriosis that had given rise to the abdominopelvic tu-\nmors, along with bilateral ovarian tumors. The presence\nof endometriosis foci in the right ovarian tumor of our pa-\ntient favors at least its primary nature at this site, and we\ncould not speculate about the true nature of the initial\nabdominopelvic tumor as it had been diagnosed elsewhere\noutside our hospital. Also, all these abdominopelvic tu-\nmors could be metastases from the right ovarian ESS\nclinically and radiologically missed out at the initial evalu-\nation of our patient. However, the fact that we have no\nidea about the initial tumor of our patient does not affect\nthe accuracy of our current histological diagnosis. In the\nliterature cases of disseminated EESS with misleading clin-\nical presentation have been reported, Mourra et al. have\nreported a case of a rectosigmoid ESS presenting with epi-\ngastric pain due to portal vein thrombosis [ 11].\nThe definitive diagnosis of ESS relies on pathology as\nimaging techniques do not provide specific signs. In fact\nthe histologic diagnosis of low grade ESS is often\nstraightforward when in uterine location, challenges\narise when the tumors are found in inhabitual\nextra-uterine locations [ 1–3, 12]. Typically, ESS presents\nas a neoplasm that resembles proliferative phase endo-\nmetrial stroma, with diffuse architecture and mono-\nmorphic cells with oval to spindle nuclei; mitotic count\nis variable and this criterion is no longer considered by\nthe current World Health Organisation (WHO) classifi-\ncation of tumors of female reproductive organs [ 3, 12].\nThe tumor stroma has a rich vascular network of small\nvessels sometimes with hyalinized walls, reminiscent of\nendometrial spirale arterioles, and the tumor cells are\nfrequently arranged in a whorling pattern around these\nFig. 2 Histologic aspects of the ovarian tumors. a (right ovary): the histological image showing ovarian parenchyma infiltrated by a diffuse\ntumoral proliferation. A focus of endometriosis is shown (Hematoxylin and eosin stain × 100). b: the tumor cells are round to spindle with oval\nhyperchromatic nuclei and moderate cytological atypia. The tumor stroma showed numerous juxtaposed small arterioles with sometimes\nhyalinazed walls. Tumor cells surrounded these vessels in a striking whorling pattern (Hematoxylin and eosin stain × 200)\nFig. 3 a (Endometriosis): a focus of regular dilated endometrioid glands embedded in the tumor (Hematoxylin and eosin stain × 200). b: At the\nperipheral ovarian parenchyma, a tongue-like protrusion in the vessel walls is seen (Hematoxylin and eosin stain × 100)\nEfared et al. Gynecologic Oncology Research and Practice             (2019) 6:2 Page 3 of 7\n\nvessels [ 1, 3, 12]. Sometimes inhabitual features of ESS\ncould be found: smooth muscle differentiation, myxoid\nbackground, fibroblastic appearance, calcifications, epi-\nthelioid differentiation, sex cord-like differentiation, clear\ncells differenciation, ...etc. [ 1–3]. The tumor borders are\nusually irregular with vascular invasion and tongue-like\nprojections into vessels wall. At immunohistochemistry,\ntypically ESS stains positive for CD10, vimentin, WT-1,\nER, PR, and negative for SMA, desmin, CD34, CD31, in-\nhibin, calretinin [ 3, 12]. However, areas of sex-cord dif-\nferenciation stain positive for inhibin and calretinin, also\nsmooth muscle differenciation areas are positive for\nsmooth muscle immunomarkers (SMA, desmin) [ 12].\nThe most common genetic abnormality in low-grade\nESS is t(7,17)(p15;q21) resulting in the fusion of JAZF1\nand SUZ12 (JJAZ1) genes at 7p15 and 17q21 respect-\nively [ 3, 13]. However Amador-Ortiz et al. have recently\nshown that this genetic abnormality is rarely found in\ntheir 6 reported cases of EESS (1 case out of 6) [ 14].\nThe inhabitual locations of ESS (extra-uterine sites)\nmake the diagnosis very challenging for both clinicians\nand pathologists. In their series of EESS, Masand et al.\nreported that initial misdiagnoses were: ovarian stromal\nneoplasm, leiomyosarcoma, gastrointestinal stromal\ntumor (GIST), adult granulosa cell tumor, juvenile gran-\nulosa cell tumor, liposarcoma, small round blue cell\ntumor, adenosarcoma, cellular fibroma, malignant per-\nipheral nerve sheath tumor, atypical stromal endometri-\nosis, and poorly differentiated synovial sarcoma [ 1]. A\npart from the extra-uterine locations, these erroneous\ndiagnoses could be in part due to many changes that oc-\ncurred in histologic classification of ESS during recent\nyears. Our case has been misdiagnosed initially as sex\nstromal tumor and as smooth muscle tumor. In fact,\ncases of ESS with unusual morphologic features (sex--\ncord differention, smooth muscle differentiation,...) pose\ndifferential diagnoses with sex-cord stromal tumors or\nsmooth muscle tumors. However, these unusual features\nare often focal in ESS, and the characteristic diffuse\narchitecture with striking vascular-rich stroma with\nwhorling pattern should lead to correct diagnosis. Ovar-\nian ESS with spindle cells could be mistaken for metas-\ntases from GIST or other sarcoma [ 2]. A minimal\nimmunohistochemical panels can easily rule out these\ndifferential diagnoses: inhibin, calretinin positive in\nsex-cord stromal tumors and negative in ESS, muscle\nmarkers (SMA, desmin, caldesmone) positive in smooth\nmuscle tumors, CD117 and DOG-1 positive in GIST and\nnegative in ESS. Another differential diagnosis of EESS\nis metastasis from a primary uterine ESS. To claim the\ndiagnosis of EESS, the status of the uterus should be de-\ntermined by imaging techniques or by a thorough\nmacroscopic sampling when the uterus is resected [ 1, 2].\nOur patient had no clinical, radiological or macroscopic\nevidence of any uterine lesions and histomorphologic\nfeatures were characteristic of low grade ESS. The im-\nmunohistochemical phenotype was also compatible with\nESS (positivity of ER, PR, CD10).\nThe low grade extra-uterine endometrioid stromal sar-\ncoma (EESS) is considered as an indolent neoplasm with\na propensity for late recurrences despite the fact that pa-\ntients frequently presented with advanced tumor stages\nFig. 4 Immunohistochemical features of the tumor (× 200). a: tumor cells are positive for CD 10. b: tumor cells stain positive for\nprogesterone receptors\nFig. 5 Immunostaining for smooth muscle actin (SMA) is negative in\ntumor cells, but highlights the tumor stromal rich-vasculature with\nhyalinazed vessels (× 200)\nEfared et al. Gynecologic Oncology Research and Practice             (2019) 6:2 Page 4 of 7\n\n[1, 2, 10]. The therapeutic management is not well de-\nfined due to the rarity of EESS, surgical treatment is the\nideal option however adjuvant therapy (hormonal ther-\napy, chemotherapy or radiation therapy) should be con-\nsidered in patients with advanced tumor stages [ 1, 10].\nWe have found only 89 reported cases of primary\novarian ESS in the English literature [ 1, 2, 4, 10, 14–29].\nTable 1 summerises some features of these reported\ncases of ovarian ESS. The histopathologic terminology\nand diagnostic criteria for ovarian ESS have greatly\nTable 1 Reported cases of ovarian endometrioid stromal sarcoma\nReferences No of cases Age/Yr Laterality Size Endom. Metastasis Treatment Follow-up\nKoller and Rygh [ 15] 1 56 Left NA + + S + R NED (15 Mo)\nBenjamin and\nCampbell [16]\n1 37 Bilateral 6\ncm\n+ + S NED (5 weeks)\nPalladino and Trousdell [ 17] 1 42 Bilateral NA + – S DOD (16.5 yr)\nGruskin et al. [ 18] 1 47 Left 15\ncm\n+ – S NED (1 yr)\nAzoury and Woodruff [ 19] 2 41* Left (1 case) Right\n(1 case)\nNA + (2\ncases)\n+ (1 case) S + R DOD (2 yr) NED (24 yr)\nSilverberg and Fernandez [ 20] 3 48* Left (2 case) Right\n(1 case)\n9.33\ncm*\n+( 2\ncases)\n+( 3\ncases)\nS (2 cases) S +\nM (1 case)\nNED (3 cases; 3.16 yr.*)\nBaiocchi et al. [ 21] 1 50 Left 12\ncm\n+ + S + M NED (10 Mo)\nFukunaga et al. [ 22] 1 40 Bilateral 15\ncm\n+ + S + M NED (16 Mo)\nMitchard et al. [ 23] 1 35 Right 4\ncm\n++ S N A\nGeas et al. [ 24] 1 45 Bilateral 15\ncm\n+ + S + M NED (36 Mo)\nKim et al. [ 25] 1 50 Bilateral 6\ncm\n+ + S + M + R AWD (3 Mo)\nLan et al. [ 26] 2 45.5* Left (1 case) Right\n(1 case)\nNA + (2\ncases)\n+ S + M (2 cases) NED (2 cases; 8.5 yr.*)\nAmador-Ortiz et al. [ 14]3 4 2 * Right (1 case) Left\n(1 case) Bilateral (1\ncase)\nNA + (2\ncases)\nNA NA NA\nMasand et al. [ 1] 25 50.56* 1 ov (15 cases\nBilateral (10 cases)\nNA + (9\ncases)\n+ (22\ncases)\nS (7 cases) S +\nM (16 cases) S\n+ R (2 cases)\nNED (17 cases; 78,17 Mo*)\nAWD (2 cases; 33 Mo*) DOD\n(1 case; 228 Mo*) NA (5\ncases)\nOliva et al. [ 2] 27 56* Right (9 cases) Left\n(8 cases) Bilateral (8\ncases) NA (2 cases)\n9.5\ncm*\n+ (16\ncases)\n+ (20\ncases)\nS (25 cases) S\n+ M (1 case) S\n+M+R ( 1\ncase)\nNED (10 cases; 10,3 yr.*)\nAWD (5 cases; 13 yr.*) DOD\n(6 cases; 6,8 yr.*) NA (6 cases)\nBack et al. [ 4] 1 40 Bilateral 6\ncm\n+ + S + M NED (14 Mo)\nKikuchi et al. [ 27] 1 65 Right 12\ncm\n– + S + M DOD (2 Yr)\nXie et al. [ 10] 14 49.1 * Right (7 cases) Left\n(4 cases) Bilateral (3\ncases)\n9.5\ncm*\n+( 6\ncases)\n+( 8\ncases)\nS (2 cases) S +\nM (10 cases) S\n+M+R ( 2\ncases)\nNED (9 cases) AWD (3 cases)\n(65 Mo*) DOD (2 cases)\nIlanthodi et al. [ 28] 1 34 Left 11\ncm\n++ S + M + R N A\nWang et al. [ 29] 1 42 Left 5\ncm\n– + S NED (10 Mo)\nOur case 1 64 Bilateral 6\ncm\n+ + S + M NED (7 Mo)\n*= average; + = present; − = absent; ov = ovary, yr. = year, Mo = month, Endom. = endometriosis, S = surgical treatment, M = medical treatment (chemotherapy\nand/or hormonal therapy), R = radiation therapy, NA = not available, NED = no evidence of disease, AWD = alive with disease, DOD = died of disease\nEfared et al. Gynecologic Oncology Research and Practice             (2019) 6:2 Page 5 of 7\n\nchanged across years, making very approximative any at-\ntempt to conduct a precise retrospective literature re-\nview. Endometrioid stromal sarcoma has been\ndesignated previously as stromal endometriosis [ 15, 16],\nendometrial stromatosis [ 18] or endolymphatic stromal\nmyosis [ 20]. The mean age of our 90 cases (previous\ncases and our current case) of primary ovarian ESS is\n46.62 years (range of 34 –65 years). Most patients pre-\nsented with metastases (67 patients, 74.44%), the tumor\nwas bilateral in 29 cases (32.22%), left-sided in 22 cases\n(24.44%), right-sided in 22 patients (24.44%) while the\ntumor location was not available in 17 cases (18.88%).\nThe average tumor size was 9.42 cm (range of 4 –15 cm),\nendometriosis was found in 51 patients (56.66%). Fourty\none patients (45.55%) were treated by surgery alone, 36\ncases (40%) were treated by surgery associated with\nchemotherapy or hormonal therapy; radiation therapy\nwas associated to surgery in 4 cases (4.44%). The\nfollow-up duration ranged from 5 weeks to 24 years. Fifty\none patients (56.66%) were alive with no evidence of dis-\nease, 11 (12.22%) were alive with disease and 12 cases\n(13.33%) were died of disease whereas follow-up data\nwere not availabe in 16 cases (17.77%).\nConclusions\nExtra-uterine low grade endometrioid stromal sarcoma\n(EESS) is an extremely rare tumor with misleading clinical\npresentation and diagnostic challenge. The awareness of\nthe potential extra-uterine location of this low grade\ntumor should guide clinicians and pathologists to the cor-\nrect diagnosis as EESS has histopathological features and\nclinical behavior similar to its uterine counterpart.\nAbbreviations\nEESS: Extra-uterine endometrioid stromal sarcoma; ER: Estrogen receptors;\nESS: Endometrial stromal sarcoma; GIST: Gastrointestinal stromal tumor;\nMRI: Magnetic resonance imaging; PR: Progesterone receptors; SMA: Smooth\nmuscle actin; WHO: World health organisation\nAcknowledgements\nNot applicable.\nFunding\nThe authors received no specific funding for this study.\nAvailability of data and materials\nAll data generated or analysed during this study are included in this article.\nAuthor’s contributions\nBE, wrote the article and made substantial contributions to conception and\ndesign of the article; ISS, FE, NH, and LC have been involved in drafting the\nmanuscript and revising it critically for important intellectual content. HEF\nhas been involved in drafting the manuscript and revising it critically for\nimportant intellectual content. All authors read and approved the final\nversion of the manuscript.\nEthics approval and consent to participate\nNot applicable.\nConsent for publication\nNot applicable.\nCompeting interests\nAll authors declare that they have no competing interest.\nPublisher’sN o t e\nSpringer Nature remains neutral with regard to jurisdictional claims in\npublished maps and institutional affiliations.\nAuthor details\n1Department of pathology, Hassan II University Hospital, Fès, Morocco.\n2Department of pathology, FSS, UAM, Niamey, Niger. 3Laboratory of\nBiomedical and Translational Research, Faculty of Medicine and\nPharmacology, Sidi Mohamed Ben Abdellah University, Fès, Morocco.\nReceived: 19 November 2018 Accepted: 16 January 2019\nReferences\n1. Masand RP, Euscher ED, Deavers MT, Malpica A. Endometrioid stromal\nsarcoma: a clinicopathologic study of 63 cases. Am J Surg Pathol. 2013;37:\n1635–47.\n2. Oliva E, Egger J-F, Young RH. Primary endometrioid stromal sarcoma of the\novary: a clinicopathologic study of 27 cases with morphologic and\nbehavioral features similar to those of uterine low-grade endometrial\nstromal sarcoma. Am J Surg Pathol. 2014;38:305 –15.\n3. Nucci MR. Practical issues related to uterine pathology: endometrial stromal\ntumors. Mod Pathol. 2016;29(Suppl 1):S92 –103.\n4. Back JA, Choi MG, Ju UC, Kang WD, Kim SM. A case of advanced-stage\nendometrial stromal sarcoma of the ovary arising from endometriosis.\nObstet Gynecol Sci. 2016;59:323 –7.\n5. Clair K, Wolford J, Veran-Taguibao S, Kim G, Eskander RN. Primary low-grade\nendometrial stromal sarcoma of the omentum. Gynecol Oncol Rep. 2017;21:\n119–21.\n6. Liu Z, Ding J, Li X, Yu K. Endometrial stromal sarcoma arising in vagina. Int J\nClin Exp Pathol. 2013;6:2997 –3002.\n7. Son H-J, Kim J-H, Kang D-W, Lee H-K, Park M-J, Lee SY. Primary extrauterine\nendometrial stromal sarcoma in the sigmoid colon. Ann Coloproctology.\n2015;31:68–73.\n8. Jin M, Reynolds JP, Odronic SI, Wakely PE. Primary gastric extra-uterine\nendometrial stromal sarcoma. Ann Diagn Pathol. 2014;18:187 –90.\n9. Alessandrini L, Sopracordevole F, Bertola G, Scalone S, Urbani M, Miolo G, et\nal. Primary extragenital endometrial stromal sarcoma of the lung: first\nreported case and review of literature. Diagn Pathol. 2017;12:36.\n10. Xie W, Bi X, Cao D, Yang J, Shen K, You Y. Primary endometrioid stromal\nsarcomas of the ovary: a clinicopathological study of 14 cases with a review\nof the literature. Oncotarget. 2017;8:63345 –52.\n11. Mourra N, Tiret E, Parc Y, de Saint-Maur P, Parc R, Flejou JF. Endometrial\nstromal sarcoma of the rectosigmoid colon arising in extragonadal\nendometriosis and revealed by portal vein thrombosis. Arch Pathol Lab\nMed. 2001;125:1088–90.\n12. D ’Angelo E, Prat J. Diagnostic use of immunohistochemistry in uterine\nmesenchymal tumors. Semin Diagn Pathol. 2014;31:216 –22.\n13. Lee C-H, Nucci MR. Endometrial stromal sarcoma--the new genetic\nparadigm. Histopathology. 2015;67:1 –19.\n14. Amador-Ortiz C, Roma AA, Huettner PC, Becker N, Pfeifer JD. JAZF1 and\nJJAZ1 gene fusion in primary extrauterine endometrial stromal sarcoma.\nHum Pathol. 2011;42:939 –46.\n15. Koller O, Rygh O. A case of stromal endometriosis originating from ovarian\nendometriosis. Acta Obstet Gynecol Scand. 1960;39:178 –83.\n16. Benjamin F, Campbell JA. Stromal “endometriosis” with possible ovarian\norigin. Am J Obstet Gynecol. 1960;80:449 –53.\n17. Palladino VS, Trousdell M. Extra-uterine Müllerian tumors. A review of the\nliterature and the report of a case. Cancer. 1969;23(6):1413 –22.\n18. Gruskin P, Osborne NG, Morley GW, Abell MR. Primary endometrial\nstromatosis of ovary. Report of a case. Obstet Gynecol. 1970;36(5):702 –7.\n19. Azoury RS, Woodruff JD. Primary ovarian sarcomas. Report of 43 cases from\nthe Emil Novak ovarian tumor registry. Obstet Gynecol. 1971;37(6):920 –41.\n20. Silverberg SG, Fernandez FN. Endolymphatic stromal myosis of the\novary: a report of three cases and li terature review. Gynecol Oncol\n1981;12(1):129 –138.\nEfared et al. Gynecologic Oncology Research and Practice             (2019) 6:2 Page 6 of 7\n\n21. Baiocchi G, Kavanagh JJ, Wharton JT. Endometrioid stromal sarcomas arising\nfrom ovarian and extraovarian endometriosis: report of two cases and\nreview of the literature. Gynecol Oncol. 1990;36(1):147 –51.\n22. Fukunaga M, Ishihara A, Ushigome S. Extrauterine low-grade endometrial\nstromal sarcoma: report of three cases. Pathol Int. 1998;48(4):297 –302.\n23. Mitchard JR, Lott M, Afifi RA, Hirschowitz L. Low-grade endometrial stromal\nsarcoma with glandular differentiation arising in ovarian endometriosis. J\nObstet Gynaecol. 2004;24(5):596 –7.\n24. Geas FL, Tewari DS, Rutgers JK, Tewari KS, Berman ML. Surgical\ncytoreduction and hormone therapy of an advanced endometrial stromal\nsarcoma of the ovary. Obstet Gynecol. 2004;103(5 Pt 2):1051 –4.\n25. Kim JY, Hong SY, Sung HJ, Oh HK, Koh SB. A case of multiple metastatic\nlow-grade endometrial stromal sarcoma arising from an ovarian\nendometriotic lesion. J Gynecol Oncol. 2009;20(2):122 –5.\n26. Lan C, Huang X, Lin S, Cai M, Liu J. Endometrial stromal sarcoma arising\nfrom endometriosis: a clinicopathological study and literature review.\nGynecol Obstet Investig. 2012;74(4):288 –97.\n27. Kikuchi N, Sugita S, Nakanishi K, Sugawara T, Segawa K, et al. Ovarian high-\ngrade endometrioid stromal sarcoma with YWHAE and NUTM2B\nrearrangements. Pathol Int. 2017;67(6):327 –9.\n28. Ilanthodi S, Meghashree V, Pai MR. Primary ovarian Endometrioid stromal\nsarcoma presenting with infertility. J Clin Diagn Res. 2017;11(3):ED05 –7.\n29. Wang W, Zhuang Y, Zhou F, Huang L. Ovarian mucinous borderline tumor\naccompanied by LGESS with myxoid change: a case report and literature\nreview. Eur J Med Res. 2017;22(1):52.\nEfared et al. Gynecologic Oncology Research and Practice             (2019) 6:2 Page 7 of 7","source_license":"CC0","license_restricted":false}