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doi:10.1111/jog.12358
J. Obstet. Gynaecol. Res. Vol. 40, No. 5: 1426–1430, May 2014
Polypoid endometriosis of the ovary mimicking ovarian carcinoma dissemination: A case report and literature review Yasushi Yamada1, Tsutomu Miyamoto1, Akiko Horiuchi1,2, Ayumi Ohya3 and Tanri Shiozawa1 1
Department of Obstetrics and Gynecology, 3Department of Radiology, Shinshu University School of Medicine, and Horiuchi Ladies’ Clinic, Matsumoto, Japan
2
Abstract Polypoid endometriosis is a rare type of endometriosis. We report a case of polypoid endometriosis of the ovary mimicking ovarian carcinoma with peritoneal dissemination. Computed tomography and magnetic resonance imaging showed a left ovarian endometriotic cyst containing several nodules in the cystic wall that displayed enhancement, and pelvic nodules on the right ovary. A preoperative or intraoperative diagnosis to avoid the unnecessary extended operation is important for such disease. Retrospective magnetic resonance imaging analysis identified a peculiar finding for polypoid endometriosis: all solid nodules had a round and smooth shape and displayed a low-signal-intense marginal edge on T2-weighted images, suggesting that this is an important finding for differentiating polypoid endometriosis from ovarian carcinoma arising from endometriosis. Key words: differential diagnosis, magnetic resonance imaging, ovarian cancer, polypoid endometriosis.
Introduction Endometriosis is a common gynecologic disease, affecting approximately 10% of women of reproductive age. It is classified as a tumor-like lesion in the current World Health Organization classification, but it carries an increased risk of developing malignancy.1 The formation of solid nodules is thought to be the most important hallmark of ovarian carcinoma arising from endometriotic cysts. Polypoid endometriosis is a rare type of endometriosis, first described by Mostoufizadeh and Scully as a distinctive variant of endometriosis with ‘histologic features simulating those of an endometrial polyp’.2 We report a case of polypoid endometriosis presenting with several nodules in an ovarian cyst and multiple peritoneal nodules, which led to the preoperative diag-
nosis of ovarian carcinoma with peritoneal dissemination. Retrospective analysis of the patient’s magnetic resonance imaging (MRI) identified characteristic findings of polypoid endometriosis, which could be useful for its preoperative diagnosis.
Case Report The patient was a 29-year-old woman (0G0P) with dysmenorrhea for 4 years. She visited a gynecological clinic, and a left ovarian cyst was detected. She was then referred to our hospital. A pelvic examination revealed a left adnexal mass, which was proved to be a left ovarian cyst measuring 6 cm in the greatest diameter, containing low-level internal echoes in the transvaginal ultrasonography (TVU) (Fig. 1a). The right ovary was found to be normal. MRI showed a
Received: February 14 2013. Accepted: November 12 2013. Reprint request to: Dr Tsutomu Miyamoto, Department of Obstetrics and Gynecology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan. Email: [email protected]
1426
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
MRI findings of polypoid endometriosis
Figure 1 The imaging findings obtained by (a) transvaginal ultrasonography (TVU) and (b–d) magnetic resonance imaging (MRI). (a) TVU revealed a cystic mass, which contained fluid displaying heterogeneous ground glass echogenicity and a solid projection (arrows), in the left ovary. (b) Axial T1-WI showed a left adnexal bilocular cyst. One cyst was located medially (*) and showed low signal intensity, and the other cyst was located laterally (**) and displayed high signal intensity. Arrow indicates one of the low-signal-intense nodules of 1.6 cm in diameter in the dorsal part of the cyst wall (arrow). (c) Axial T2-WI. The cystic content in the medial cyst showed high signal intensity (*), suggesting a serous cyst, and that in the lateral cyst showed high signal intensity (**), indicating intra-cystic hemorrhaging. The one of nodules (arrow) in the left adnexal cyst and one of nodules on the right ovary (arrowhead) showed high signal intensity with a low-signal-intense marginal edge and a smooth/round shape. (d) Axial gadolinium enhanced and fat-suppressed T1-WI demonstrated the nodules in the cystic wall (arrow) and the peritoneal nodules (arrowhead) were well enhanced and associated and accompanied with less enhanced marginal edge.
multilocular cyst in the left ovary (Fig. 1b,c,d). Fluid in the medial lumen showed low signal intensity on T1-weighted images (T1-WI) and high on T2-weighted images (T2-WI), suggesting a serous cyst. The lateral cyst contained fluid displaying high signal intensities on both T1-WI and T2-WI suggesting blood and several round and smooth shaped nodules up to 1.6 cm in diameter. The solid parts of these nodules showed high signal intensity on T2-WI, but the marginal edge of them showed low signal intensity on T2-WI. Those nodules were strongly enhanced by gadolinium contrast material with the marginal edge being less enhanced (Fig. 1d). In addition, several solid nodules were seen close to the normal right ovary, which were also enhanced by gadolinium, suggesting disseminated metastasis (Fig. 1c,d). There was no ascites. Her serum level of cancer antigen (CA)125
was 121.9 U/ml. The preoperative diagnosis was left ovarian carcinoma arising from endometriosis with peritoneal dissemination. At laparotomy, a left ovarian cyst of approximately 6 cm in diameter was detected, and solid nodules were noted on the right ovary, omentum, and rectum, suggesting ovarian carcinoma and its dissemination. As intraoperative consultation for the specimen from all of these nodules resulted in the diagnosis of endometriosis (Fig. 2b), left salpingo-oophorectomy was additionally performed. Macroscopically, the left ovarian cyst had an irregularly thickened cystic wall and red-brown elevated foci with smooth surface (Fig. 2a). The microscopic findings of formalin-fixed paraffin-embedded tissue sections from the medial cyst of the left ovary indicated that it was a simple cyst. The lateral cyst was covered
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
1427
Y. Yamada et al.
Figure 2 The macroscopic findings of (a) the removed left ovarian cyst and (b) peritoneal nodules. (a) The left ovarian cyst contained chocolate-colored hemorrhagic material and nodular components (circles), and (b) the nodules had a smooth surface and small hemorrhagic foci. (c–e) Microscopic findings of the nodule in the cystic wall and (f) peritoneal nodule. (c) The cyst was covered with a monolayer of endometrial glands, consistent with ordinary endometriosis. (d) The nodule in the cystic wall contained an area of proliferation of benign endometrial glands with highly vascularized endometrioidtype stroma, reminiscent of a typical uterine endometrial polyp. (e) High magnification of the section demonstrated endometrioid-type glands without atypia. (f) The peritoneal nodule on the right ovary also showed a normal endometriallike gland with stroma.
with a monolayer of normal-looking endometrial glands and endometrial stroma, consistent with ordinary endometriosis (Fig 2c). The nodular foci in the cystic wall consisted of proliferation of endometrialtype gland and endometrial stroma containing the large vessels (Fig 2d). These findings displayed the typical features of a uterine endometrial polyp. Some endometrial glands were dilated, but lacked cellular atypia (Fig. 2e). The peritoneal nodules on the right ovary also consisted of benign endometrial glands and endometrial stroma (Fig. 2f). Therefore, our final diagnosis was ‘multiple polypoid endometriosis in the pelvis’. After the operation, the patient was treated with dienogest, and no recurrence occurred for 28 months postoperatively.
Discussion Polypoid endometriosis was first reported as a rare and distinctive variant of endometriosis.2 This condi-
1428
tion has been described as ‘exophytic or polypoid, tumor-like masses’, which can be mistaken for a neoplasm during preoperative and intraoperative assessment.3–6 In the present case, despite our preoperative diagnosis of ovarian carcinoma arising from endometriosis based on the MRI findings of solid nodules in the cyst showing high signal intensities on both T1-WI and T2-WI, the final pathological diagnosis proved to be polypoid endometriosis. A retrospective analysis of MRI of the nodules in the left ovarian cystic wall revealed two important findings for polypoid endometriosis: the low-signal-intense marginal edge on T2-WI, and the nodules with round and smooth shape. In cases of ovarian carcinoma arising from endometriosis, no such low-signal-intense marginal edge on T2-WI is observed, and the margin of the nodule is irregular.5,7 Meticulous observation of MRI for these findings might differentiate polypoid endometriosis from endometriosis-related ovarian carcinoma.
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
7
BSO, bilateral salpingo-oophorectomy; High, high-intensity; Iso, iso-intensity; Low, low-intensity; LSO, left salpingo-oophorectomy; MRI, magnetic resonance imaging; OM, omentectomy; TAH, total abdominal hysterectomy.
LSO Ovarian carcinoma Iso Ovary, omentum, rectum
High
Low
Enhanced
+
Partial cystectomy Urachal carcinoma – Enhanced 6
5
2 3 4
1
Kano and Kanda (2003)8 Kraft et al. (2006)3 Ozaki et al. (2008)4 Takeuchi et al. (2008)5 Marugami et al. (2008)9 Lambrechts et al. (2011)6 This case
High Unknown Bladder
Low
Transurethral resection Urethral polyp – Enhanced High Low
Unclear
TAH+BSO +OM LSO TAH+LSO Iso High High Low Iso Unknown
Ovary Uterus Pouch of Douglas Ureter
Unknown Low Low
Unknown Enhanced Enhanced
– – –
Growing cervical mass Ovarian carcinoma Ovarian carcinoma Malignant tumor – Unknown Unknown Unknown High Cervix
MRI T2-WI of tumor center T1-WI Site Author Case no.
Table 1 Polypoid endometriosis: MRI finding of reported cases
T2-WI of tumor margin
T1-WI with gadolinium
Peritoneal lesion
Preoperative diagnosis
Treatment
TAH+LSO +tumorectomy
MRI findings of polypoid endometriosis
Our literature review using PubMed identified approximately 40 cases of polypoid endometriosis.3– 6,8–10 The mean age was 52.2 years (23–89 years of age). The lesion was most often found in the ovary (12 cases) but also in the colon (eight cases), uterus (seven cases), bladder/ureter (seven cases), pelvic peritoneum (seven cases), or others. Of the 12 ovarian cases, six were found within endometriotic cyst, and four were associated with peritoneal lesions, including the uterine serosa, tube and omentum. Ascites was not noted except in one case. Of these 40 cases, MRI pictures in the reports were available in six cases whose predominant sites were the cervix, ovary, uterus, Pouch of Douglas, ureter and bladder (Table 1).3–6,8,9 Although the signal intensity of the mass on T1-WI ranged from low to high, T2-WI showed high signal intensity in four cases, and these masses were enhanced by gadolinium. Importantly, like the present case, the low-signal-intense marginal edge on T2-WI, a finding indicative of polypoid endometriosis, was seen in three cases (cases no. 3, 4 and 6, in the uterus, Pouch of Douglas and bladder). In particular, Takeuchi et al. also suggested in their case report that a hypointense rim-like structure surrounding polypoid masses on T2-WI might be a diagnostic clue to polypoid endometriosis.5 This is the first case of polypoid endometriosis of the ovary presenting with this peculiar MRI finding. It should be noted that the detection of multiple peritoneal lesions in the abdominal cavity, which could suggest ovarian carcinoma dissemination, could also be associated with polypoid endometriosis. In our case, fortunately, extensive surgery was avoided by performing intraoperative consultation. However, radical hysterectomy was reportedly carried out in a case of polypoid endometriosis involving multiple polypoid masses in the pelvis.11 Awareness of characteristic MRI findings of polypoid endometriosis could possibly prevent unnecessary surgery. In conclusion, the MRI findings that we detected in this study, namely, a solid nodule displaying lowsignal-intense marginal edge on T2-WI and a smooth margin, might be helpful for distinguishing polypoid endometriosis from carcinomas accompanied by endometriotic cysts of the ovary.
Disclosure No author has any potential conflict of interest to disclose.
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
1429
Y. Yamada et al.
References 1. Kobayashi H. Ovarian cancer in endometriosis: Epidemiology, natural history, and clinical diagnosis. Int J Clin Oncol 2009; 14: 378–382. 2. Mostoufizadeh M, Scully RE. Malignant tumors arising in endometriosis. Clin Obstet Gynecol 1980; 23: 951–963. 3. Kraft JK, Hughes T. Polypoid endometriosis and other benign gynaecological complications associated with tamoxifen therapy: a case to illustrate features on magnetic resonance imaging. Clin Radiol 2006; 61: 198–201. 4. Ozaki K, Gabata T, Tanaka M et al. Polypoid endometriosis: An uncommon and distinctive variant of endometriosis. European J Radiology Extra 2008; 65: 97–100. 5. Takeuchi M, Matsuzaki K, Furumoto H, Nishitani H. Case report: A case of polypoid endometriosis. MR pathological correlation. Br J Radiol 2008; 81: e118–e119. 6. Lambrechts S, Van Calsteren K, Capoen A et al. Polypoid endometriosis of the bladder during pregnancy mimicking
1430
7.
8.
9.
10.
11.
urachal carcinoma. Ultrasound Obstet Gynecol 2011; 38: 475– 478. Wu TT, Coakley FV, Qayyum A Yeh BM, Chen LM. Magnetic resonance imaging of ovarian cancer arising in endometriomas. J Comput Assist Tumogr 2004; 28: 836–838. Kano H, Kanda H. Cervical endometriosis presented as a polypoid mass of portio cervix uteri. J Obstet Gynaecol 2003; 23: 84–85. Marugami N, Hirohashi S, Kitano S et al. Polypoid endometriosis of the ureter mimicking fibroepithelial polyps. Radiat Med 2008; 26: 42–45. Parker RL, Dadmanesh F, Young RH, Clement PB. Polypoid endometriosis: A clinicopathologic analysis of 24 cases and a review of the literature. Am J Surg Pathol 2004; 28: 285– 297. Laird LA, Hoffman JS, Omrani A. Multifocal polypoid endometriosis presenting as huge pelvic masses causing deep vein thrombosis. Arch Pathol Lab Med 2004; 128: 561– 564.
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
doi:10.1111/jog.12358
J. Obstet. Gynaecol. Res. Vol. 40, No. 5: 1426–1430, May 2014
Polypoid endometriosis of the ovary mimicking ovarian carcinoma dissemination: A case report and literature review Yasushi Yamada1, Tsutomu Miyamoto1, Akiko Horiuchi1,2, Ayumi Ohya3 and Tanri Shiozawa1 1
Department of Obstetrics and Gynecology, 3Department of Radiology, Shinshu University School of Medicine, and Horiuchi Ladies’ Clinic, Matsumoto, Japan
2
Abstract Polypoid endometriosis is a rare type of endometriosis. We report a case of polypoid endometriosis of the ovary mimicking ovarian carcinoma with peritoneal dissemination. Computed tomography and magnetic resonance imaging showed a left ovarian endometriotic cyst containing several nodules in the cystic wall that displayed enhancement, and pelvic nodules on the right ovary. A preoperative or intraoperative diagnosis to avoid the unnecessary extended operation is important for such disease. Retrospective magnetic resonance imaging analysis identified a peculiar finding for polypoid endometriosis: all solid nodules had a round and smooth shape and displayed a low-signal-intense marginal edge on T2-weighted images, suggesting that this is an important finding for differentiating polypoid endometriosis from ovarian carcinoma arising from endometriosis. Key words: differential diagnosis, magnetic resonance imaging, ovarian cancer, polypoid endometriosis.
Introduction Endometriosis is a common gynecologic disease, affecting approximately 10% of women of reproductive age. It is classified as a tumor-like lesion in the current World Health Organization classification, but it carries an increased risk of developing malignancy.1 The formation of solid nodules is thought to be the most important hallmark of ovarian carcinoma arising from endometriotic cysts. Polypoid endometriosis is a rare type of endometriosis, first described by Mostoufizadeh and Scully as a distinctive variant of endometriosis with ‘histologic features simulating those of an endometrial polyp’.2 We report a case of polypoid endometriosis presenting with several nodules in an ovarian cyst and multiple peritoneal nodules, which led to the preoperative diag-
nosis of ovarian carcinoma with peritoneal dissemination. Retrospective analysis of the patient’s magnetic resonance imaging (MRI) identified characteristic findings of polypoid endometriosis, which could be useful for its preoperative diagnosis.
Case Report The patient was a 29-year-old woman (0G0P) with dysmenorrhea for 4 years. She visited a gynecological clinic, and a left ovarian cyst was detected. She was then referred to our hospital. A pelvic examination revealed a left adnexal mass, which was proved to be a left ovarian cyst measuring 6 cm in the greatest diameter, containing low-level internal echoes in the transvaginal ultrasonography (TVU) (Fig. 1a). The right ovary was found to be normal. MRI showed a
Received: February 14 2013. Accepted: November 12 2013. Reprint request to: Dr Tsutomu Miyamoto, Department of Obstetrics and Gynecology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan. Email: [email protected]
1426
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
MRI findings of polypoid endometriosis
Figure 1 The imaging findings obtained by (a) transvaginal ultrasonography (TVU) and (b–d) magnetic resonance imaging (MRI). (a) TVU revealed a cystic mass, which contained fluid displaying heterogeneous ground glass echogenicity and a solid projection (arrows), in the left ovary. (b) Axial T1-WI showed a left adnexal bilocular cyst. One cyst was located medially (*) and showed low signal intensity, and the other cyst was located laterally (**) and displayed high signal intensity. Arrow indicates one of the low-signal-intense nodules of 1.6 cm in diameter in the dorsal part of the cyst wall (arrow). (c) Axial T2-WI. The cystic content in the medial cyst showed high signal intensity (*), suggesting a serous cyst, and that in the lateral cyst showed high signal intensity (**), indicating intra-cystic hemorrhaging. The one of nodules (arrow) in the left adnexal cyst and one of nodules on the right ovary (arrowhead) showed high signal intensity with a low-signal-intense marginal edge and a smooth/round shape. (d) Axial gadolinium enhanced and fat-suppressed T1-WI demonstrated the nodules in the cystic wall (arrow) and the peritoneal nodules (arrowhead) were well enhanced and associated and accompanied with less enhanced marginal edge.
multilocular cyst in the left ovary (Fig. 1b,c,d). Fluid in the medial lumen showed low signal intensity on T1-weighted images (T1-WI) and high on T2-weighted images (T2-WI), suggesting a serous cyst. The lateral cyst contained fluid displaying high signal intensities on both T1-WI and T2-WI suggesting blood and several round and smooth shaped nodules up to 1.6 cm in diameter. The solid parts of these nodules showed high signal intensity on T2-WI, but the marginal edge of them showed low signal intensity on T2-WI. Those nodules were strongly enhanced by gadolinium contrast material with the marginal edge being less enhanced (Fig. 1d). In addition, several solid nodules were seen close to the normal right ovary, which were also enhanced by gadolinium, suggesting disseminated metastasis (Fig. 1c,d). There was no ascites. Her serum level of cancer antigen (CA)125
was 121.9 U/ml. The preoperative diagnosis was left ovarian carcinoma arising from endometriosis with peritoneal dissemination. At laparotomy, a left ovarian cyst of approximately 6 cm in diameter was detected, and solid nodules were noted on the right ovary, omentum, and rectum, suggesting ovarian carcinoma and its dissemination. As intraoperative consultation for the specimen from all of these nodules resulted in the diagnosis of endometriosis (Fig. 2b), left salpingo-oophorectomy was additionally performed. Macroscopically, the left ovarian cyst had an irregularly thickened cystic wall and red-brown elevated foci with smooth surface (Fig. 2a). The microscopic findings of formalin-fixed paraffin-embedded tissue sections from the medial cyst of the left ovary indicated that it was a simple cyst. The lateral cyst was covered
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
1427
Y. Yamada et al.
Figure 2 The macroscopic findings of (a) the removed left ovarian cyst and (b) peritoneal nodules. (a) The left ovarian cyst contained chocolate-colored hemorrhagic material and nodular components (circles), and (b) the nodules had a smooth surface and small hemorrhagic foci. (c–e) Microscopic findings of the nodule in the cystic wall and (f) peritoneal nodule. (c) The cyst was covered with a monolayer of endometrial glands, consistent with ordinary endometriosis. (d) The nodule in the cystic wall contained an area of proliferation of benign endometrial glands with highly vascularized endometrioidtype stroma, reminiscent of a typical uterine endometrial polyp. (e) High magnification of the section demonstrated endometrioid-type glands without atypia. (f) The peritoneal nodule on the right ovary also showed a normal endometriallike gland with stroma.
with a monolayer of normal-looking endometrial glands and endometrial stroma, consistent with ordinary endometriosis (Fig 2c). The nodular foci in the cystic wall consisted of proliferation of endometrialtype gland and endometrial stroma containing the large vessels (Fig 2d). These findings displayed the typical features of a uterine endometrial polyp. Some endometrial glands were dilated, but lacked cellular atypia (Fig. 2e). The peritoneal nodules on the right ovary also consisted of benign endometrial glands and endometrial stroma (Fig. 2f). Therefore, our final diagnosis was ‘multiple polypoid endometriosis in the pelvis’. After the operation, the patient was treated with dienogest, and no recurrence occurred for 28 months postoperatively.
Discussion Polypoid endometriosis was first reported as a rare and distinctive variant of endometriosis.2 This condi-
1428
tion has been described as ‘exophytic or polypoid, tumor-like masses’, which can be mistaken for a neoplasm during preoperative and intraoperative assessment.3–6 In the present case, despite our preoperative diagnosis of ovarian carcinoma arising from endometriosis based on the MRI findings of solid nodules in the cyst showing high signal intensities on both T1-WI and T2-WI, the final pathological diagnosis proved to be polypoid endometriosis. A retrospective analysis of MRI of the nodules in the left ovarian cystic wall revealed two important findings for polypoid endometriosis: the low-signal-intense marginal edge on T2-WI, and the nodules with round and smooth shape. In cases of ovarian carcinoma arising from endometriosis, no such low-signal-intense marginal edge on T2-WI is observed, and the margin of the nodule is irregular.5,7 Meticulous observation of MRI for these findings might differentiate polypoid endometriosis from endometriosis-related ovarian carcinoma.
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
7
BSO, bilateral salpingo-oophorectomy; High, high-intensity; Iso, iso-intensity; Low, low-intensity; LSO, left salpingo-oophorectomy; MRI, magnetic resonance imaging; OM, omentectomy; TAH, total abdominal hysterectomy.
LSO Ovarian carcinoma Iso Ovary, omentum, rectum
High
Low
Enhanced
+
Partial cystectomy Urachal carcinoma – Enhanced 6
5
2 3 4
1
Kano and Kanda (2003)8 Kraft et al. (2006)3 Ozaki et al. (2008)4 Takeuchi et al. (2008)5 Marugami et al. (2008)9 Lambrechts et al. (2011)6 This case
High Unknown Bladder
Low
Transurethral resection Urethral polyp – Enhanced High Low
Unclear
TAH+BSO +OM LSO TAH+LSO Iso High High Low Iso Unknown
Ovary Uterus Pouch of Douglas Ureter
Unknown Low Low
Unknown Enhanced Enhanced
– – –
Growing cervical mass Ovarian carcinoma Ovarian carcinoma Malignant tumor – Unknown Unknown Unknown High Cervix
MRI T2-WI of tumor center T1-WI Site Author Case no.
Table 1 Polypoid endometriosis: MRI finding of reported cases
T2-WI of tumor margin
T1-WI with gadolinium
Peritoneal lesion
Preoperative diagnosis
Treatment
TAH+LSO +tumorectomy
MRI findings of polypoid endometriosis
Our literature review using PubMed identified approximately 40 cases of polypoid endometriosis.3– 6,8–10 The mean age was 52.2 years (23–89 years of age). The lesion was most often found in the ovary (12 cases) but also in the colon (eight cases), uterus (seven cases), bladder/ureter (seven cases), pelvic peritoneum (seven cases), or others. Of the 12 ovarian cases, six were found within endometriotic cyst, and four were associated with peritoneal lesions, including the uterine serosa, tube and omentum. Ascites was not noted except in one case. Of these 40 cases, MRI pictures in the reports were available in six cases whose predominant sites were the cervix, ovary, uterus, Pouch of Douglas, ureter and bladder (Table 1).3–6,8,9 Although the signal intensity of the mass on T1-WI ranged from low to high, T2-WI showed high signal intensity in four cases, and these masses were enhanced by gadolinium. Importantly, like the present case, the low-signal-intense marginal edge on T2-WI, a finding indicative of polypoid endometriosis, was seen in three cases (cases no. 3, 4 and 6, in the uterus, Pouch of Douglas and bladder). In particular, Takeuchi et al. also suggested in their case report that a hypointense rim-like structure surrounding polypoid masses on T2-WI might be a diagnostic clue to polypoid endometriosis.5 This is the first case of polypoid endometriosis of the ovary presenting with this peculiar MRI finding. It should be noted that the detection of multiple peritoneal lesions in the abdominal cavity, which could suggest ovarian carcinoma dissemination, could also be associated with polypoid endometriosis. In our case, fortunately, extensive surgery was avoided by performing intraoperative consultation. However, radical hysterectomy was reportedly carried out in a case of polypoid endometriosis involving multiple polypoid masses in the pelvis.11 Awareness of characteristic MRI findings of polypoid endometriosis could possibly prevent unnecessary surgery. In conclusion, the MRI findings that we detected in this study, namely, a solid nodule displaying lowsignal-intense marginal edge on T2-WI and a smooth margin, might be helpful for distinguishing polypoid endometriosis from carcinomas accompanied by endometriotic cysts of the ovary.
Disclosure No author has any potential conflict of interest to disclose.
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
1429
Y. Yamada et al.
References 1. Kobayashi H. Ovarian cancer in endometriosis: Epidemiology, natural history, and clinical diagnosis. Int J Clin Oncol 2009; 14: 378–382. 2. Mostoufizadeh M, Scully RE. Malignant tumors arising in endometriosis. Clin Obstet Gynecol 1980; 23: 951–963. 3. Kraft JK, Hughes T. Polypoid endometriosis and other benign gynaecological complications associated with tamoxifen therapy: a case to illustrate features on magnetic resonance imaging. Clin Radiol 2006; 61: 198–201. 4. Ozaki K, Gabata T, Tanaka M et al. Polypoid endometriosis: An uncommon and distinctive variant of endometriosis. European J Radiology Extra 2008; 65: 97–100. 5. Takeuchi M, Matsuzaki K, Furumoto H, Nishitani H. Case report: A case of polypoid endometriosis. MR pathological correlation. Br J Radiol 2008; 81: e118–e119. 6. Lambrechts S, Van Calsteren K, Capoen A et al. Polypoid endometriosis of the bladder during pregnancy mimicking
1430
7.
8.
9.
10.
11.
urachal carcinoma. Ultrasound Obstet Gynecol 2011; 38: 475– 478. Wu TT, Coakley FV, Qayyum A Yeh BM, Chen LM. Magnetic resonance imaging of ovarian cancer arising in endometriomas. J Comput Assist Tumogr 2004; 28: 836–838. Kano H, Kanda H. Cervical endometriosis presented as a polypoid mass of portio cervix uteri. J Obstet Gynaecol 2003; 23: 84–85. Marugami N, Hirohashi S, Kitano S et al. Polypoid endometriosis of the ureter mimicking fibroepithelial polyps. Radiat Med 2008; 26: 42–45. Parker RL, Dadmanesh F, Young RH, Clement PB. Polypoid endometriosis: A clinicopathologic analysis of 24 cases and a review of the literature. Am J Surg Pathol 2004; 28: 285– 297. Laird LA, Hoffman JS, Omrani A. Multifocal polypoid endometriosis presenting as huge pelvic masses causing deep vein thrombosis. Arch Pathol Lab Med 2004; 128: 561– 564.
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
