ª Springer Science+Business Media New York 2014
Abdominal Imaging
Abdom Imaging (2014) DOI: 10.1007/s00261-014-0330-7
MR manifestations of uterine polypoid adenomyoma Mayumi Takeuchi, Kenji Matsuzaki, Masafumi Harada Department of Radiology, University of Tokushima, 3-18-15, Kuramoto-cho, Tokushima 7708503, Japan
Abstract Purpose: Polypoid adenomyoma (PA) is an uncommon benign tumor of the uterus appearing as a submucosal polypoid mass, or rarely as a subserosal polypoid mass. PA should be differentiated from atypical polypoid adenomyoma or malignant uterine tumors. The purpose of our case series is to evaluate magnetic resonance (MR) manifestations of PA for the differential diagnosis. Methods: Seven cases with surgically proven PA, five submucosal, and two subserosal, were evaluated. MR imaging findings including contrast enhancement in six cases (four cases with dynamic contrast-enhanced MR study), diffusion-weighted imaging (DWI) in five cases, and susceptibility weighted imaging (SWI) in two cases were retrospectively reviewed. Results: All seven lesions exhibited isointensity compared with the myometrium and 4 of 7 lesions (57%) contained high signal intensity hemorrhagic areas on T1-weighted images. On T2-weighted images, signal intensity was variable and all seven lesions contained cysts. None of five lesions with DWI exhibited high signal intensity compared with the normal myometrium. All six lesions showed intense contrast enhancement similar to that of the myometrium on post-contrast T1-weighted images. Punctate low intensity areas reflecting blood contents were revealed in all two lesions with SWI. Conclusions: Submucosal or subserosal polypoid masses containing hemorrhagic areas, and cysts reflecting functional endometrium and dilatation of endometrial glands are suggestive for PA. Intense contrast enhancement similar to that of the myometrium may be another characteristic finding for PA. Key words: Uterus—Polypoid adenomyoma—Magnetic resonance imaging (MRI)—Diffusion-weighted imaging (DWI)
Correspondence to: Mayumi Takeuchi; email: mayumi@tokushima-u. ac.jp
Adenomyoma of the uterus is an uncommon benign tumor which grows as a circumscribed mass composed of benign endometrial glands with stroma surrounded by leiomyomatous smooth muscle [1–4]. Adenomyoma may be located within the myometrium, or appear as a submucosal polypoid mass protruding into the endometrial cavity or rarely as a polypoid subserosal mass [1–4]. Submucosal polypoid adenomyoma should be differentiated from atypical polypoid adenomyoma or endometrial malignant tumors, whereas subserosal polypoid adenomyoma may mimic uterine sarcomas [1–6]. There are few studies focused on the imaging findings of polypoid adenomyoma [7–10]. Kitajima et al. reported the conventional magnetic resonance (MR) imaging findings of eight submucosal polypoid adenomyomas, and concluded that a well-defined polypoid mass protruding into the endometrial cavity, which is isointense relative to the myometrium and contains high signal foci on T1- or T2-weighted images is suggestive for polypoid adenomyoma [8]. We evaluated MR imaging manifestations of polypoid adenomyoma including contrast enhancement, diffusionweighted imaging (DWI), and susceptibility weighted imaging (SWI).
Materials and methods Patients The institutional review board approved this retrospective study, and waived the requirement for written informed consent. We experienced seven cases with surgically proven polypoid adenomyoma of the uterus who had undergone MR examinations from 2000 to 2013. A total of seven women with a mean age of 51 years (range 39–71 years) were included in the study (Table 1). Histological diagnosis of polypoid adenomyoma was made by surgical resection: five submucosal and two subserosal. The median lesion size which was the longest diameter measured by MR imaging was 65 mm (range 13–200 mm).
M. Takeuchi et al.: Uterine polypoid adenomyoma
MR imaging Patients were studied on 1.0, 1.5, and 3.0 T superconducting MR units (Impact Expert 1.0T, Siemens; Signa Excite 1.5 T, General Electric; Signa Advantage 1.5 T, General Electric; Magnetom Avanto 1.5 T, Siemens; Discovery MR 750 3.0 T, General Electric; Signa HDx 3.0 T, General Electric). Axial spin-echo or gradientecho T1-weighted images, and axial and sagittal spinecho or fast spin-echo T2-weighted images were obtained in all cases. Scan parameters of T1- and T2-weighted images varied because the study was conducted for more than 10 years. Contrast enhancement was performed with intravenous administration of gadolinium contrast agent in six cases. In 4 of 6 cases, dynamic contrastenhanced MR (DCE-MR) studies with intravenous administration of 0.1 mmol/kg of gadolinium contrast agent at 2 ml/second using 3-dimensional fast spoiled gradient-recalled echo sequence with fat suppression, for a total of 1 min 30 s duration (five acquisitions), were performed beginning at 30 s (delay) from the start of the contrast injection. Axial single-shot echo-planar DWI was obtained in five patients. The b factors were 800– 1000 s/mm2. In four lesions with DWI (b = 800 s/mm2), mean apparent diffusion coefficient (ADC) values in the solid components were measured from the ADC maps on the workstation (AW4.2). SWI was performed in two patients with subserosal polypoid adenomyoma.
Results All seven lesions showed isointensity compared with the myometrium on T1-weighted images (Figs. 1, 2, 3). Four of seven lesions (57%) contained high signal intensity hemorrhagic areas as well-demarcated hemorrhagic cysts or patchy hemorrhagic foci (Figs. 1, 2, 3). On T2weighted images, the signal of solid components of the lesions compared with the myometrium was homogeneous low intensity in three lesions (Fig. 3), homogeneous isointensity in one lesion, homogeneous slight high intensity in one lesion (Fig. 2), inhomogeneous low to slight high intensity in one lesion (Fig. 1), and inhomogeneous low to high intensity in one lesion. All seven lesions (100%) contained cysts as well-demarcated round high intensity areas on T2-weighted images, and/or as
Fig. 1. A 50-year-old woman with abnormal genital bleeding c (case 1) was studied on 3.0 T superconducting MR unit (Discovery MR 750 3.0 T, General Electric). A Sagittal fast spin-echo T2-weighted image (repetition time (TR)/echo time (TE) = 5240/121.3) shows a well-demarcated pedunculated solid and cystic mass protruding into the uterine cavity (arrow). Solid portion of the mass exhibits heterogeneously low to slightly high signal intensity relative to the myometrium. B Dynamic contrast-enhanced (DCE) MR images (i. pre-contrast image; ii. arterial phase image; iii. venous phase image; iv. equilibrium phase image, three-dimensional fast spoiled gradient-recalled echo sequence with fat suppression; TR/TE, 4.8/2.1; flip angle, 12°) show gradually increasing contrast enhancement pattern. Cystic areas of the mass show high signal intensity reflecting their hemorrhagic contents on precontrast image (arrowhead). C Axial post-contrast gradientecho T1-weighted image with fat suppression (4.0/1.7; flip angle, 12°) shows intense contrast enhancement similar to that of the myometrium in solid portion of the mass (arrow). D Axial echo-planar diffusion-weighted image (4000/55.8, b = 800 s/mm2) shows no prominent signal increase in solid portion of the mass (arrow) compared with the normal myometrium. Cystic areas show high signal intensity due to their hemorrhagic contents (arrowhead). E Corresponding ADC map shows inhomogeneous relative high ADC (mean ADC: 1.37 9 10-3 mm2/s) of the mass (arrow). F Photograph of the cut surface of the gross specimen shows polypoid mass (arrow) containing cystic areas in the uterine cavity.
well-demarcated round unenhanced areas on post-contrast T1-weighted images (Figs. 1, 2, 3). None of five lesions (0%) with DWI exhibited high signal intensity compared with the normal myometrium (Figs. 1, 2, 3). The ADC value of the solid components of four lesions was 1.46 ± 0.34 9 10-3 mm2/s [range (1.15–1.95) 9 10-3 mm2/s]. The solid components of all six lesions with contrast enhancement (100%) showed intense contrast enhancement similar to that of the myometrium on postcontrast T1-weighted images (Figs. 1, 2, 3). The enhancing patterns of DCE-MR study showed a plateau after rapid increase in 3 of 4 lesions (75%) (Fig. 2) and a gradual increase in the other one lesion (25%) (Fig. 1). On SWI, punctate low intensity areas reflecting blood contents were revealed in 2 of 2 (100%) subserosal lesions. These low intensity areas on SWI tended to be
Table 1. Seven cases of uterine polypoid adenomyoma No.
Age
Site
SI on T1WIa
SI on T2WIa
SI on DWI
CEa
DCE pattern
1 2 3 4 5 6 7
50 42 39 71 64 52 39
Submucosal Submucosal Submucosal Submucosal Submucosal Subserosal Subserosal
Iso Iso Iso Iso Iso Iso Iso
Low to slight high Slight high Iso Low Low Low Low to high
NVH NVH NVH ND ND NVH NVH
Iso Iso ND Iso Iso Iso Iso
Gradual increase Rapid and plateau ND ND ND Rapid and plateau Rapid and plateau
a
with high with high
with high with high
Compared with the myometrium SI signal intensity, CE contrast enhancement, NVH not very high, ND not done
M. Takeuchi et al.: Uterine polypoid adenomyoma
M. Takeuchi et al.: Uterine polypoid adenomyoma
Fig. 2. A 42-year-old woman with abnormal genital bleeding c (case 2) was studied on 1.5 T superconducting MR unit (Magnetom Avanto 1.5T, Siemens). A Sagittal fast spin-echo T2-weighted image (5250/127.0) shows a well-demarcated pedunculated solid mass protruding into the uterine cavity (arrow). Solid portion of the mass exhibits slight high signal intensity relative to the myometrium and contains small high signal intensity cyst. B DCE-MR images (i. pre-contrast image; ii. arterial phase image; iii. venous phase image; iv. equilibrium phase image, three-dimensional fast spoiled gradient-recalled echo sequence with fat suppression; TR/TE, 6/ 2.4; flip angle, 15°) show plateau after rapid increase pattern. The mass shows a rapid signal increase on the arterial phase and intense contrast enhancement continues till the end of the DCE-MR study. A small cystic area of the mass shows high signal intensity (arrowhead) reflecting its hemorrhagic contents on pre-contrast image. C Axial echo-planar diffusionweighted image (8800/69, b = 1000 s/mm2) shows no prominent signal increase in the mass (arrow), whereas surrounding normal endometrium exhibits high signal intensity.
higher in number and larger in size than high intensity areas on T1-weighted images (Fig. 3).
Discussion
Fig. 1.
continued
Adenomyoma is a benign mixed epithelial-mesenchymal tumor of the uterus, and not as localized adenomyosis [1–4]. Endometrial polyp with abundant smooth muscle (adenomyomatous polyp), which accounts for 1.3% of endometrial polyps, is histologically identical to adenomyoma, and may be referred to as submucosal polypoid adenomyoma [4]. Submucosal polypoid adenomyoma typically occurs in premenopausal women and may manifest as abnormal genital bleeding [1–4]. Polypoid adenomyoma is a benign tumor, and submucosal polypoid adenomyoma should be distinguished from atypical polypoid adenomyoma (APA), or other malignant endometrial tumors such as endometrial carcinoma, carcinosarcoma, or adenosarcoma [1–6]. APA is an uncommon variant of adenomyoma, which is characterized by irregularly crowded endometrioid glands with cytologic atypia, and of low malignant potential [5, 6]. Rarely, polypoid adenomyoma may manifest as a polypoid subserosal mass as subserosal polypoid adenomyoma, and should be distinguished from malignant myometrial tumors such as uterine sarcomas [1]. In our study, high incidence of cyst formation and hemorrhage is observed, which is compatible with previous reports [8], and may be the characteristic features of polypoid adenomyoma reflecting functional endometrium and cystic dilatation of endometrial glands [1–4]. Intense contrast enhancement similar to that of the myometrium on post-contrast T1-weighted images may be another characteristic MR feature of polypoid adenomyoma; however, other common mesenchymal tumors such as leiomyoma may often show intense contrast
M. Takeuchi et al.: Uterine polypoid adenomyoma
M. Takeuchi et al.: Uterine polypoid adenomyoma
Fig. 3. A 52-year-old woman with mild lower abdominal pain (case 6) was studied on 3.0 T superconducting MR unit (Discovery MR 750 3.0 T, General Electric). A Axial fast spinecho T2-weighted image (5500/113.5) shows a low signal intensity large uterine subserosal polypoid mass (arrow) containing small cysts and high intensity areas (arrowheads). B Axial gradient-echo T1-weighted image with fat suppression (3.9/1.7; flip angle, 12°) shows the mass (arrow) as isointensity compared with the myometrium and small high intensity hemorrhagic foci (arrowhead) are observed. C Axial susceptibility weighted imaging (T2 star weighted MR angiography: SWAN; TR/TE, 42.4/27.3; flip angle, 12°) shows small hemorrhagic foci as punctate low intensity areas (arrowheads) in the mass (arrow), and demonstrates more sensitive detection
of hemorrhagic foci than corresponding T1-weighted image with fat suppression (B). D Axial echo-planar diffusionweighted image (4000/56, b = 800 s/mm2) shows no prominent signal increase in solid portion of the mass (arrow). Some small cysts and hemorrhagic foci appear as high intensity areas (arrowheads). E Corresponding ADC map shows inhomogeneous ADC (mean ADC: 1.15 9 10-3 mm2/ s) of the mass (arrow). F Post-contrast axial gradient-echo T1-weighted image with fat suppression (3.9/1.7) shows intense contrast enhancement of the mass (arrow) similar to that of the myometrium (arrowhead). G Photomicrograph of the mass with low power magnification (hematoxylin and eosin) shows endometrial glands and stroma overlying hypertrophied smooth muscle.
enhancement [11]. DCE-MR study showed two different patterns: a plateau after rapid increase and a gradual increase, possibly depending on the amount of thickwalled vessels which are commonly observed in the
stroma of adenomyomas, and on the variable cellularity of smooth muscle component [1, 2]. Abundant endometrial tissue, cyst formation, edema or congestion in polypoid adenomyoma may cause
M. Takeuchi et al.: Uterine polypoid adenomyoma
heterogeneous T2 prolongation resulting in malignancy mimicking imaging manifestation on T2-weighted images; however, no prominent signal increase compared with the normal myometrium on DWI with relatively high ADC may be a suggestive finding for its benignity. DWI may aid in differentiating benign uterine lesions from malignancies such as uterine sarcomas, or endometrial carcinoma [12–15]. Malignant uterine tumors usually exhibit high signal intensity on DWI, and the mean ADC values of malignancies have been shown to be significantly lower than those of benign uterine lesions [12–15]. APA may also show restricted diffusion reflecting its high cellularity [16, 17]. DWI may be helpful in distinguishing polypoid adenomyoma from uterine malignant tumors or APA. Cysts as well as hemorrhage into the cysts or stroma are commonly observed in which the sectioned surface of polypoid adenomyomas, whereas usual benign leiomyomas rarely contain hemorrhagic areas [1, 2]. T1-weighted image demonstrates subacute hemorrhage as high intensity due to T1-shortening by methemoglobin, whereas SWI can reveal hemorrhage in different phases, from acute to chronic phase, as low signal intensity area mainly due to T2* shortening by deoxyhemoglobin and hemosiderin [18, 19]. In this study, SWI was more sensitive in detecting hemorrhagic foci in two subserosal adenomyomas than T1-weighted images, and may be helpful for the diagnosis. Our study has several limitations: the retrospective nature of the study, small number of patients, and six different MR machines used. Prospective studies with larger populations are needed to support our results. We conclude that submucosal or subserosal polypoid masses containing hemorrhagic areas and cysts reflecting functional endometrium and dilatation of endometrial glands are suggestive for polypoid adenomyoma. Intense contrast enhancement similar to that of the myometrium may be another characteristic MR finding for polypoid adenomyoma. DWI may be helpful in distinguishing polypoid adenomyoma from malignant uterine tumors, or APA. References
Fig. 3.
continued
1. Gilks CB, Clement PB, Hart WR, Young RH (2000) Uterine adenomyomas excluding atypical polypoid adenomyomas and adenomyomas of endocervical type: a clinicopathologic study of 30 cases of an underemphasized lesion that may cause diagnostic problems with brief consideration of adenomyomas of other female genital tract sites. Int J Gynecol Pathol 19:195–205 2. Tahlan A, Nanda A, Mohan H (2006) Uterine adenomyoma: a clinicopathologic review of 26 cases and a review of the literature. Int J Gynecol Pathol 25:361–365 3. Clement PB, Scully RE (1988) Uterine tumors with mixed epithelial and mesenchymal elements. Semin Diagn Pathol 5:199–222 4. Nasu K, Sugano T, Miyakawa I (1995) Adenomyomatous polyp of the uterus. Int J Gynaecol Obstet 48:319–321 5. Longacre TA, Chung MH, Rouse RV, Hendrickson MR (1996) Atypical polypoid adenomyofibromas (atypical polypoid
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6. 7. 8.
9. 10. 11.
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adenomyomas) of the uterus. A clinicopathologic study of 55 cases. Am J Surg Pathol 20:1–20 Mazur MT (1981) Atypical polypoid adenomyomas of the endometrium. Am J Surg Pathol 5:473–482 Lee EJ, Han JH, Ryu HS (2004) Polypoid adenomyomas: sonohysterographic and color Doppler findings with histopathologic correlation. J Ultrasound Med 23:1421–1429 Kitajima K, Imanaka K, Kuwata Y, Hashimoto K, Sugimura K (2007) Magnetic resonance imaging of typical polypoid adenomyoma of the uterus in 8 patients: correlation with pathological findings. J Comput Assist Tomogr 31:463–468 Takeuchi M, Matsuzaki K, Uehara H, Shimazu H, Nishitani H (2005) A case of adenomyomatous polyp of the uterus associated with tamoxifen therapy. Radiat Med 23:432–434 Tamai K, Koyama T, Saga T, et al. (2008) The utility of diffusionweighted MR imaging for differentiating uterine sarcomas from benign leiomyomas. Eur Radiol 18:723–730 Hricak H, Finck S, Honda G, Go¨ranson H (1992) MR imaging in the evaluation of benign uterine masses: value of gadopentetate dimeglumine-enhanced T1-weighted images. AJR Am J Roentgenol 158:1043–1050 Tamai K, Koyama T, Saga T, et al. (2008) The utility of diffusionweighted MR imaging for differentiating uterine sarcomas from benign leiomyomas. Eur Radiol 18:723–730
13. Takeuchi M, Matsuzaki K, Nishitani H (2009) Hyperintense uterine myometrial masses on T2-weighted magnetic resonance imaging: differentiation with diffusion-weighted magnetic resonance imaging. J Comput Assist Tomogr 33:834–837 14. Tamai K, Koyama T, Saga T, et al. (2007) Diffusion-weighted MR imaging of uterine endometrial cancer. J Magn Reson Imaging 26:682–687 15. Takeuchi M, Matsuzaki K, Nishitani H (2009) Diffusion-weighted magnetic resonance imaging of endometrial cancer: differentiation from benign endometrial lesions and preoperative assessment of myometrial invasion. Acta Radiol 50:947–953 16. Horikawa M, Shinmoto H, Soga S, et al. (2012) Multiple atypical polypoid adenomyoma of the uterus. Jpn J Radiol 30:606–611 17. Nakai G, Kitano R, Yamamoto K, Higashiyama A, Juri H, Tsuboyama T, Yamamoto K, Yamada T, Hirose Y, Ohmichi M, Narumi Y (2014) Magnetic resonance imaging findings in atypical polypoid adenomyoma. J Comput Assist Tomogr [Epub ahead of print] 18. Sehgal V, Delproposto Z, Haddar D, et al. (2006) Susceptibilityweighted imaging to visualize blood products and improve tumor contrast in the study of brain masses. J Magn Reson Imaging 24:41–51 19. Takeuchi M, Matsuzaki K (2011) Adenomyosis: usual and unusual imaging manifestations, pitfalls, and problem-solving MR imaging techniques. Radiographics 31:99–115
Abdominal Imaging
Abdom Imaging (2014) DOI: 10.1007/s00261-014-0330-7
MR manifestations of uterine polypoid adenomyoma Mayumi Takeuchi, Kenji Matsuzaki, Masafumi Harada Department of Radiology, University of Tokushima, 3-18-15, Kuramoto-cho, Tokushima 7708503, Japan
Abstract Purpose: Polypoid adenomyoma (PA) is an uncommon benign tumor of the uterus appearing as a submucosal polypoid mass, or rarely as a subserosal polypoid mass. PA should be differentiated from atypical polypoid adenomyoma or malignant uterine tumors. The purpose of our case series is to evaluate magnetic resonance (MR) manifestations of PA for the differential diagnosis. Methods: Seven cases with surgically proven PA, five submucosal, and two subserosal, were evaluated. MR imaging findings including contrast enhancement in six cases (four cases with dynamic contrast-enhanced MR study), diffusion-weighted imaging (DWI) in five cases, and susceptibility weighted imaging (SWI) in two cases were retrospectively reviewed. Results: All seven lesions exhibited isointensity compared with the myometrium and 4 of 7 lesions (57%) contained high signal intensity hemorrhagic areas on T1-weighted images. On T2-weighted images, signal intensity was variable and all seven lesions contained cysts. None of five lesions with DWI exhibited high signal intensity compared with the normal myometrium. All six lesions showed intense contrast enhancement similar to that of the myometrium on post-contrast T1-weighted images. Punctate low intensity areas reflecting blood contents were revealed in all two lesions with SWI. Conclusions: Submucosal or subserosal polypoid masses containing hemorrhagic areas, and cysts reflecting functional endometrium and dilatation of endometrial glands are suggestive for PA. Intense contrast enhancement similar to that of the myometrium may be another characteristic finding for PA. Key words: Uterus—Polypoid adenomyoma—Magnetic resonance imaging (MRI)—Diffusion-weighted imaging (DWI)
Correspondence to: Mayumi Takeuchi; email: mayumi@tokushima-u. ac.jp
Adenomyoma of the uterus is an uncommon benign tumor which grows as a circumscribed mass composed of benign endometrial glands with stroma surrounded by leiomyomatous smooth muscle [1–4]. Adenomyoma may be located within the myometrium, or appear as a submucosal polypoid mass protruding into the endometrial cavity or rarely as a polypoid subserosal mass [1–4]. Submucosal polypoid adenomyoma should be differentiated from atypical polypoid adenomyoma or endometrial malignant tumors, whereas subserosal polypoid adenomyoma may mimic uterine sarcomas [1–6]. There are few studies focused on the imaging findings of polypoid adenomyoma [7–10]. Kitajima et al. reported the conventional magnetic resonance (MR) imaging findings of eight submucosal polypoid adenomyomas, and concluded that a well-defined polypoid mass protruding into the endometrial cavity, which is isointense relative to the myometrium and contains high signal foci on T1- or T2-weighted images is suggestive for polypoid adenomyoma [8]. We evaluated MR imaging manifestations of polypoid adenomyoma including contrast enhancement, diffusionweighted imaging (DWI), and susceptibility weighted imaging (SWI).
Materials and methods Patients The institutional review board approved this retrospective study, and waived the requirement for written informed consent. We experienced seven cases with surgically proven polypoid adenomyoma of the uterus who had undergone MR examinations from 2000 to 2013. A total of seven women with a mean age of 51 years (range 39–71 years) were included in the study (Table 1). Histological diagnosis of polypoid adenomyoma was made by surgical resection: five submucosal and two subserosal. The median lesion size which was the longest diameter measured by MR imaging was 65 mm (range 13–200 mm).
M. Takeuchi et al.: Uterine polypoid adenomyoma
MR imaging Patients were studied on 1.0, 1.5, and 3.0 T superconducting MR units (Impact Expert 1.0T, Siemens; Signa Excite 1.5 T, General Electric; Signa Advantage 1.5 T, General Electric; Magnetom Avanto 1.5 T, Siemens; Discovery MR 750 3.0 T, General Electric; Signa HDx 3.0 T, General Electric). Axial spin-echo or gradientecho T1-weighted images, and axial and sagittal spinecho or fast spin-echo T2-weighted images were obtained in all cases. Scan parameters of T1- and T2-weighted images varied because the study was conducted for more than 10 years. Contrast enhancement was performed with intravenous administration of gadolinium contrast agent in six cases. In 4 of 6 cases, dynamic contrastenhanced MR (DCE-MR) studies with intravenous administration of 0.1 mmol/kg of gadolinium contrast agent at 2 ml/second using 3-dimensional fast spoiled gradient-recalled echo sequence with fat suppression, for a total of 1 min 30 s duration (five acquisitions), were performed beginning at 30 s (delay) from the start of the contrast injection. Axial single-shot echo-planar DWI was obtained in five patients. The b factors were 800– 1000 s/mm2. In four lesions with DWI (b = 800 s/mm2), mean apparent diffusion coefficient (ADC) values in the solid components were measured from the ADC maps on the workstation (AW4.2). SWI was performed in two patients with subserosal polypoid adenomyoma.
Results All seven lesions showed isointensity compared with the myometrium on T1-weighted images (Figs. 1, 2, 3). Four of seven lesions (57%) contained high signal intensity hemorrhagic areas as well-demarcated hemorrhagic cysts or patchy hemorrhagic foci (Figs. 1, 2, 3). On T2weighted images, the signal of solid components of the lesions compared with the myometrium was homogeneous low intensity in three lesions (Fig. 3), homogeneous isointensity in one lesion, homogeneous slight high intensity in one lesion (Fig. 2), inhomogeneous low to slight high intensity in one lesion (Fig. 1), and inhomogeneous low to high intensity in one lesion. All seven lesions (100%) contained cysts as well-demarcated round high intensity areas on T2-weighted images, and/or as
Fig. 1. A 50-year-old woman with abnormal genital bleeding c (case 1) was studied on 3.0 T superconducting MR unit (Discovery MR 750 3.0 T, General Electric). A Sagittal fast spin-echo T2-weighted image (repetition time (TR)/echo time (TE) = 5240/121.3) shows a well-demarcated pedunculated solid and cystic mass protruding into the uterine cavity (arrow). Solid portion of the mass exhibits heterogeneously low to slightly high signal intensity relative to the myometrium. B Dynamic contrast-enhanced (DCE) MR images (i. pre-contrast image; ii. arterial phase image; iii. venous phase image; iv. equilibrium phase image, three-dimensional fast spoiled gradient-recalled echo sequence with fat suppression; TR/TE, 4.8/2.1; flip angle, 12°) show gradually increasing contrast enhancement pattern. Cystic areas of the mass show high signal intensity reflecting their hemorrhagic contents on precontrast image (arrowhead). C Axial post-contrast gradientecho T1-weighted image with fat suppression (4.0/1.7; flip angle, 12°) shows intense contrast enhancement similar to that of the myometrium in solid portion of the mass (arrow). D Axial echo-planar diffusion-weighted image (4000/55.8, b = 800 s/mm2) shows no prominent signal increase in solid portion of the mass (arrow) compared with the normal myometrium. Cystic areas show high signal intensity due to their hemorrhagic contents (arrowhead). E Corresponding ADC map shows inhomogeneous relative high ADC (mean ADC: 1.37 9 10-3 mm2/s) of the mass (arrow). F Photograph of the cut surface of the gross specimen shows polypoid mass (arrow) containing cystic areas in the uterine cavity.
well-demarcated round unenhanced areas on post-contrast T1-weighted images (Figs. 1, 2, 3). None of five lesions (0%) with DWI exhibited high signal intensity compared with the normal myometrium (Figs. 1, 2, 3). The ADC value of the solid components of four lesions was 1.46 ± 0.34 9 10-3 mm2/s [range (1.15–1.95) 9 10-3 mm2/s]. The solid components of all six lesions with contrast enhancement (100%) showed intense contrast enhancement similar to that of the myometrium on postcontrast T1-weighted images (Figs. 1, 2, 3). The enhancing patterns of DCE-MR study showed a plateau after rapid increase in 3 of 4 lesions (75%) (Fig. 2) and a gradual increase in the other one lesion (25%) (Fig. 1). On SWI, punctate low intensity areas reflecting blood contents were revealed in 2 of 2 (100%) subserosal lesions. These low intensity areas on SWI tended to be
Table 1. Seven cases of uterine polypoid adenomyoma No.
Age
Site
SI on T1WIa
SI on T2WIa
SI on DWI
CEa
DCE pattern
1 2 3 4 5 6 7
50 42 39 71 64 52 39
Submucosal Submucosal Submucosal Submucosal Submucosal Subserosal Subserosal
Iso Iso Iso Iso Iso Iso Iso
Low to slight high Slight high Iso Low Low Low Low to high
NVH NVH NVH ND ND NVH NVH
Iso Iso ND Iso Iso Iso Iso
Gradual increase Rapid and plateau ND ND ND Rapid and plateau Rapid and plateau
a
with high with high
with high with high
Compared with the myometrium SI signal intensity, CE contrast enhancement, NVH not very high, ND not done
M. Takeuchi et al.: Uterine polypoid adenomyoma
M. Takeuchi et al.: Uterine polypoid adenomyoma
Fig. 2. A 42-year-old woman with abnormal genital bleeding c (case 2) was studied on 1.5 T superconducting MR unit (Magnetom Avanto 1.5T, Siemens). A Sagittal fast spin-echo T2-weighted image (5250/127.0) shows a well-demarcated pedunculated solid mass protruding into the uterine cavity (arrow). Solid portion of the mass exhibits slight high signal intensity relative to the myometrium and contains small high signal intensity cyst. B DCE-MR images (i. pre-contrast image; ii. arterial phase image; iii. venous phase image; iv. equilibrium phase image, three-dimensional fast spoiled gradient-recalled echo sequence with fat suppression; TR/TE, 6/ 2.4; flip angle, 15°) show plateau after rapid increase pattern. The mass shows a rapid signal increase on the arterial phase and intense contrast enhancement continues till the end of the DCE-MR study. A small cystic area of the mass shows high signal intensity (arrowhead) reflecting its hemorrhagic contents on pre-contrast image. C Axial echo-planar diffusionweighted image (8800/69, b = 1000 s/mm2) shows no prominent signal increase in the mass (arrow), whereas surrounding normal endometrium exhibits high signal intensity.
higher in number and larger in size than high intensity areas on T1-weighted images (Fig. 3).
Discussion
Fig. 1.
continued
Adenomyoma is a benign mixed epithelial-mesenchymal tumor of the uterus, and not as localized adenomyosis [1–4]. Endometrial polyp with abundant smooth muscle (adenomyomatous polyp), which accounts for 1.3% of endometrial polyps, is histologically identical to adenomyoma, and may be referred to as submucosal polypoid adenomyoma [4]. Submucosal polypoid adenomyoma typically occurs in premenopausal women and may manifest as abnormal genital bleeding [1–4]. Polypoid adenomyoma is a benign tumor, and submucosal polypoid adenomyoma should be distinguished from atypical polypoid adenomyoma (APA), or other malignant endometrial tumors such as endometrial carcinoma, carcinosarcoma, or adenosarcoma [1–6]. APA is an uncommon variant of adenomyoma, which is characterized by irregularly crowded endometrioid glands with cytologic atypia, and of low malignant potential [5, 6]. Rarely, polypoid adenomyoma may manifest as a polypoid subserosal mass as subserosal polypoid adenomyoma, and should be distinguished from malignant myometrial tumors such as uterine sarcomas [1]. In our study, high incidence of cyst formation and hemorrhage is observed, which is compatible with previous reports [8], and may be the characteristic features of polypoid adenomyoma reflecting functional endometrium and cystic dilatation of endometrial glands [1–4]. Intense contrast enhancement similar to that of the myometrium on post-contrast T1-weighted images may be another characteristic MR feature of polypoid adenomyoma; however, other common mesenchymal tumors such as leiomyoma may often show intense contrast
M. Takeuchi et al.: Uterine polypoid adenomyoma
M. Takeuchi et al.: Uterine polypoid adenomyoma
Fig. 3. A 52-year-old woman with mild lower abdominal pain (case 6) was studied on 3.0 T superconducting MR unit (Discovery MR 750 3.0 T, General Electric). A Axial fast spinecho T2-weighted image (5500/113.5) shows a low signal intensity large uterine subserosal polypoid mass (arrow) containing small cysts and high intensity areas (arrowheads). B Axial gradient-echo T1-weighted image with fat suppression (3.9/1.7; flip angle, 12°) shows the mass (arrow) as isointensity compared with the myometrium and small high intensity hemorrhagic foci (arrowhead) are observed. C Axial susceptibility weighted imaging (T2 star weighted MR angiography: SWAN; TR/TE, 42.4/27.3; flip angle, 12°) shows small hemorrhagic foci as punctate low intensity areas (arrowheads) in the mass (arrow), and demonstrates more sensitive detection
of hemorrhagic foci than corresponding T1-weighted image with fat suppression (B). D Axial echo-planar diffusionweighted image (4000/56, b = 800 s/mm2) shows no prominent signal increase in solid portion of the mass (arrow). Some small cysts and hemorrhagic foci appear as high intensity areas (arrowheads). E Corresponding ADC map shows inhomogeneous ADC (mean ADC: 1.15 9 10-3 mm2/ s) of the mass (arrow). F Post-contrast axial gradient-echo T1-weighted image with fat suppression (3.9/1.7) shows intense contrast enhancement of the mass (arrow) similar to that of the myometrium (arrowhead). G Photomicrograph of the mass with low power magnification (hematoxylin and eosin) shows endometrial glands and stroma overlying hypertrophied smooth muscle.
enhancement [11]. DCE-MR study showed two different patterns: a plateau after rapid increase and a gradual increase, possibly depending on the amount of thickwalled vessels which are commonly observed in the
stroma of adenomyomas, and on the variable cellularity of smooth muscle component [1, 2]. Abundant endometrial tissue, cyst formation, edema or congestion in polypoid adenomyoma may cause
M. Takeuchi et al.: Uterine polypoid adenomyoma
heterogeneous T2 prolongation resulting in malignancy mimicking imaging manifestation on T2-weighted images; however, no prominent signal increase compared with the normal myometrium on DWI with relatively high ADC may be a suggestive finding for its benignity. DWI may aid in differentiating benign uterine lesions from malignancies such as uterine sarcomas, or endometrial carcinoma [12–15]. Malignant uterine tumors usually exhibit high signal intensity on DWI, and the mean ADC values of malignancies have been shown to be significantly lower than those of benign uterine lesions [12–15]. APA may also show restricted diffusion reflecting its high cellularity [16, 17]. DWI may be helpful in distinguishing polypoid adenomyoma from uterine malignant tumors or APA. Cysts as well as hemorrhage into the cysts or stroma are commonly observed in which the sectioned surface of polypoid adenomyomas, whereas usual benign leiomyomas rarely contain hemorrhagic areas [1, 2]. T1-weighted image demonstrates subacute hemorrhage as high intensity due to T1-shortening by methemoglobin, whereas SWI can reveal hemorrhage in different phases, from acute to chronic phase, as low signal intensity area mainly due to T2* shortening by deoxyhemoglobin and hemosiderin [18, 19]. In this study, SWI was more sensitive in detecting hemorrhagic foci in two subserosal adenomyomas than T1-weighted images, and may be helpful for the diagnosis. Our study has several limitations: the retrospective nature of the study, small number of patients, and six different MR machines used. Prospective studies with larger populations are needed to support our results. We conclude that submucosal or subserosal polypoid masses containing hemorrhagic areas and cysts reflecting functional endometrium and dilatation of endometrial glands are suggestive for polypoid adenomyoma. Intense contrast enhancement similar to that of the myometrium may be another characteristic MR finding for polypoid adenomyoma. DWI may be helpful in distinguishing polypoid adenomyoma from malignant uterine tumors, or APA. References
Fig. 3.
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