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Fibrous tumours of the ovary: Aetiologies and MRI features
Clinical Radiology xxx (2013) e1ee8
Contents lists available at SciVerse ScienceDirect
Clinical Radiology journal homepage: www.clinicalradiologyonline.net
Pictorial Review
Fibrous tumours of the ovary: Aetiologies and MRI features P.-F. Montoriol a, *, A. Mons a, D. Da Ines a, N. Bourdel b, L. Tixier c, J.M. Garcier a a
Department of Radiology and Medical Imaging, CHU Estaing, Clermont-Ferrand, France Department of Gynaecology, CHU Estaing, Clermont-Ferrand, France c Department of Pathology, CHU Estaing, Clermont-Ferrand, France b
art icl e i nformat ion Article history: Received 28 May 2013 Received in revised form 22 June 2013 Accepted 8 July 2013
The ovaries can be affected by a vast variety of tumours, which may be benign or malignant, solid or cystic. Although ultrasonography is often the first examination performed in the evaluation of gynaecological conditions, magnetic resonance imaging is nowadays the most accurate imaging technique in the characterization of ovarian masses. Once the ovarian origin of a pelvic mass has been determined, the detection of any fibrous component within the lesion significantly reduces the spectrum of aetiologies that should be considered. Fibrotic tissue usually displays marked low-signal intensity on T2-weighted sequences at MRI, and enhancement is mostly moderate after intravenous administration of gadolinium chelates. This review aims to provide the main diagnoses to consider at MRI whenever an ovarian tumour, both purely solid or solid and cystic, contains a fibrous component, even if minimally abundant. The corresponding key imaging features are provided. Ó 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.
Introduction Magnetic resonance imaging (MRI) is an accurate technique for the evaluation of ovarian masses. The standard imaging protocol usually includes T1-weighted sequences with and without fat saturation and T2-weighted sequences, the latter being mandatory in the exploration of the female pelvis due to its excellent soft-tissue contrast. A wide range of benign or malignant lesions that may contain different types of tissue may affect the ovaries. Among those, fibrous tissue represents low-cellularity material in combination with spindle, oval, or round cells that result in collagen formation. Fibrosis typically demonstrates
* Guarantor and correspondent: P.-F. Montoriol, CHU Estaing, Department of Radiology and Medical Imaging, 1 place Lucie et Raymond Aubrac, 63003 Clermont-Ferrand, France. Tel.: þ33 (0) 4 73 755 235. E-mail address: [email protected] (P.-F. Montoriol).
intermediate signal intensity on T1-weighted sequences and very low signal intensity on T2-weighted sequences.1 The enhancement after intravenous administration of gadolinium is variable, usually moderate. The differential diagnoses of marked T2-hypointense lesions at MRI mainly include blood products and calcifications, but the distinction is easily made using side-by-side analysis with T1 sequences: haemorrhagic cysts, especially endometrioma, may display moderate low signal intensity on T2-weighted sequences but high signal intensity on T1 images, whereas calcifications would show marked low signal intensity on both sequences. Once the ovarian origin of a pelvic mass is determined, it is important to identify any fibrous component, as the spectrum of diagnoses to consider is reduced. The aim of this review is to provide the aetiologies of fibrous ovarian lesions and the corresponding MRI features. All lesions presented in this article were surgically removed and histologically proven. The key findings of fibrous ovarian lesions are summarized in Table 1.
0009-9260/$ e see front matter Ó 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.crad.2013.07.005
Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
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Table 1 Summary of key findings of fibrous ovarian lesions. Ovarian lesion
Population
Nature
Potential associated clinical features
Relevant MRI findings
Fibroma/fibrothecoma
All ages
Solid
Brenner tumour
Pre-menopausal women Post-menopausal women All ages
Solid
Pleural effusion e ascites (DemonseMeigs’ syndrome) Usually asymptomatic
Solid
Virilization
Solid and cystic
Usually asymptomatic
Solid and cystic
Excessive oestrogen production (vaginal bleeding)
Homogeneous low signal on T2 images, weak enhancement Homogeneous low signal on T2 images, at least moderate enhancement Presence of lipid components, intense enhancement of non-fibrotic portions “Black sponge” aspect, dark-signal thickening of cysts’ wall Complex mass with haemorrhagic cysts, endometrial thickening, or polyps
Solid and cystic
Tumour of the gastrointestinal tract, carcinomatous ascites
At least moderate enhancement of solid components, peritoneal implants, ascites
Leydig cell tumour Cystadenofibroma Granulosa cell tumour
Krukenberg tumour
Middle-aged and post-menopausal women All ages
Figure 1 Ovarian fibroma. (a) Typical left ovarian fibroma (white arrow; U, uterine body) in a 78-year-old asymptomatic woman, presenting as a well-delineated mass with marked homogeneous low-signal intensity on the axial fast spin-echo (FSE) T2-weighted image. (b) The lesion displays isosignal on the axial fat-saturated T1-weighted image. (c) Enhancement after gadolinium administration is weak as seen on the axial fat-saturated image following gadolinium administration. Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
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Mainly solid fibrous ovarian masses Fibroma and fibrothecoma Fibroma and fibrothecoma are benign ovarian stromal neoplasms that belong to the sex cord stromal tumours category. They account for only 4% of all ovarian neoplasms, but represent the most common primary solid tumours in asymptomatic women of all ages.2 Small lesions are often an incidental finding; larger lesions may be a cause of pelvic discomfort. Pleural effusion or ascites may be present in the classic DemonseMeigs’ syndrome. There is a histopathological overlap between those entities, but the imaging features remain similar. Fibrothecoma may have either oestrogenic or androgenic activity, which explains why endometrial hyperplasia and polyps may be associated in some cases. Typically, at MRI examination, fibroma and fibrothecoma (Fig 1) present as well delineated ovarian masses and exhibit homogeneous low signal intensity on T2-weighted images3; large lesions may appear more heterogeneous on the same sequences due to oedematous or degenerative changes,4 with areas of high signal intensity. Haemorrhagic
e3
infarction or necrosis may occur in cases of torsion; however, even in those cases, areas of low-signal intensity on T2 images remain, usually allowing the differential diagnosis with malignant ovarian neoplasms,3 and therefore, avoiding unnecessary invasive surgery. On T1-weighted sequences, the lesions are usually iso or hypointense to uterine myometrium. Enhancement is weak after gadolinium administration, significantly inferior to that of myometrium or fibroids.4
Brenner tumour Brenner tumour, formerly known as “transitional cell tumour” because of its similarity to urothelial epithelium, is a usually benign and rather uncommon epithelial ovarian lesion that accounts for 1.5e2% of all ovarian neoplasms.5 They are more commonly discovered in premenopausal women6 and are often asymptomatic, as over 50% of tumours are <2 cm in size. Borderline and malignant forms are also described but are excessively rare.7 Histopathologically, benign Brenner tumours have solid or microcystic epithelial cell nests surrounded by dense fibrous stroma.5 As a result, they typically present as
Figure 2 Brenner tumour. Left ovarian Brenner tumour in a 52 year-old asymptomatic woman with a previous history of hysterectomy for postpartum haemorrhage. (a) Axial T2 image displays a large but homogeneous low-signal pelvic mass ( ), without any cystic or haemorrhagic changes. Axial fat-saturated T1-weighted images before (b) and after (c) gadolinium administration show significant enhancement of the lesion. This imaging feature is unlikely to be found in large ovarian fibromas. Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
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homogeneous low-signal ovarian masses on T2-weighted sequences. Calcifications may be seen within the mass but are often easier to depict on computed tomography images. Although the T2-weighted imaging findings of Brenner tumours overlap with those of fibrothecomas, Brenner tumours typically demonstrate at least moderate enhancement after contrast material administration (Fig 2), whereas fibrothecomas are typically hypovascular.8 Furthermore, unlike fibromas or fibrothecomas, large Brenner tumours tend not to display cystic or oedematous changes.6 Another imaging characteristic is the association with mucinous cystadenomas in up to 20% of cases, leading to a more complex, cystic and solid appearance,8 the latter component representing the Brenner tumour.
Leydig cell tumour Leydig cell tumours belong to the group of steroid cell tumours, which are very rare ovarian neoplasms accounting for less than 0.5% of all ovarian tumours.9 They are usually benign and predominantly seen in postmenopausal women. These lesions contain Leydig cells, lutein cells, and adrenocortical cells in various amounts together with a fibrous stroma and are often associated with a virilization syndrome.10 Most Leydig cell tumours present as small (<3 cm) and unilateral solid masses (Fig 3). Lipid components, which appear as areas of elevated signal on T1- and T2-weighted images, may be seen. However, the signal on T2 sequences
Figure 3 Leydig cell tumour. Right ovarian Leydig cell tumour (white arrow) in a 67-year-old woman presenting with hirsutism. (a) Coronal T2 image displays a small right ovarian mass (U, uterine body) with a peripheral low-signal fibrous component. The centre of the lesion shows a more cellular nature with elevated signal intensity and enhances strongly after gadolinium administration [(b) axial T1-weighted image and (c) axial T1-weighted contrast enhanced image]. Evocative clinical features are very useful to raise the diagnosis. Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
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is variable, depending on the extent of fibrous stroma. Intense enhancement of the non-fibrotic portions after intravenous administration of gadolinium is usually displayed.10
Fibrous and cystic ovarian masses Cystadenofibroma Cystadenofibromas are rare and usually benign epithelial ovarian lesions, accounting for about 1.7% of all ovarian neoplasms.11 They are often asymptomatic although large lesions may be a cause of pelvic pain or discomfort. No age
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prevalence is noted. Several histological subtypes (serous, mucinous, endometrioid, clear cell, or mixed) are described according to the epithelial component.8 All subtypes contain various amounts of fibrous stroma.12 Borderline variants are very rare and indistinguishable from benign lesions at MRI,13 but, because of this malignant potential, cystadenofibromas tend to be removed surgically. At MRI, the appearance of cystadenofibromas varies depending on whether the cystic or fibrous component predominates. They typically appear as a multiloculated cystic mass with a solid fibrous component (Fig 4) displaying the characteristic low-signal intensity on T2weighted sequences8 and a “black sponge” aspect.12 In predominantly cystic lesions, diffuse or partial thickening of
Figure 4 Cystadenofibromas. Large right ovarian benign mucinous cystadenofibroma in a 58-year-old woman complaining of chronic pelvic discomfort. (a) Axial T2-weighted image shows a voluminous complex right adnexal mass (U, uterine body) with numerous cysts of variable size and a solid fibrous stroma (long black arrows). Typical dark-signal thickening of a large cystic cavity is also visible (short black arrow). (b) A few cysts contain proteinaceous material that demonstrates a slightly elevated signal intensity on the axial fat-saturated T1-weighted image ( ). (c) Enhancement of the fibrous portions is almost non-existent on the axial fat-saturated T1-weighted image following gadolinium administration. Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
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the cystic wall with a T2-dark signal intensity is another suggestive MRI finding.12 Solid fibrous portions usually display moderate enhancement after gadolinium administration, inferior to that of the myometrium.13
Granulosa cell tumour Granulosa cell tumours (GCT) belong to the group of sex cordestromal tumours and represent 70% of all sex cordestromal tumours, but account for only 2e3% of all ovarian neoplasms.10 GCT is considered a low-grade malignancy but recurrence may be seen after surgical resection.14 Two distinct types are described: the juvenile type and the adult type, the latter being the far most common (95%), usually occurring in middle-aged and postmenopausal women.10 Excessive oestrogen production may cause related symptoms such as vaginal bleeding and endometrial hyperplasia.10
These are almost always (95% of cases) unilateral tumours that may present at imaging (Fig 5) as complex cystic masses or a combination of solid, fibrous portions, haemorrhage, and cystic components 10,15. A study16 showed that two common imaging findings were large multiseptate cystic masses and medium solid lesions with internal cysts; haemorrhage within the cysts was also a frequent MRI finding.14
Krukenberg tumour Krukenberg tumours are metastatic adenocarcinomas of the ovary and account for about 5e10% of all ovarian tumours.17 They mostly originate from the stomach (70% of cases), followed by the breast, colon, and appendix, and are bilateral in 60e80% of cases.8 The ovaries usually retain their shape, in contrast with the situation of primary ovarian neoplasms.17 They usually appear as solid masses with various amounts of cystic components (Fig 6) that may
Figure 5 Granulosa cell tumour. Large granulosa cell tumour in a 56-year-old patient presenting with metrorrhagia and suspicious pelvic mass seen at ultrasound. (a) Axial T2-weighted image shows a large solid and cystic mass that was found to originate from the right ovary. Thin fibrous portions can be seen within the lesion (white arrows). (b) Numerous cysts display typical haemorrhagic changes ( ) on the axial T1-weighted image. (c) Non-fibrotic portions enhance strongly after intravenous gadolinium administration on the axial contrast-enhanced T1-weighted image. Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
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Figure 6 Krukenberg tumour. Unilateral Krukenberg tumour in a 70-year-old woman with a history of gastric adenocarcinoma recently discovered. A suspicious left adnexal mass was found at computed tomography. (a) Axial T2-weighted image displays a left ovarian mass with dark-signal fibrotic (white arrow) and neoplastic portions with a more elevated signal intensity ( ). Numerous peripheral cysts of variable size are seen. Moderate enhancement of the solid neoplastic component is seen after gadolinium injection on the (b) axial fat-saturated image and (c) axial fat-saturated contrast enhanced image. The absence of ascites or peritoneal implants makes the diagnosis difficult to establish without appropriate clinical data.
demonstrate elevated signal intensity on T1-weighted images due to mucinous filling or haemorrhagic changes. Then again, unlike primary ovarian cystadenocarcinoma, the solid component of Krukenberg tumours typically demonstrates a marked low signal on T2-weighted images, due to a dense stromal reaction.17 Moderate to marked enhancement of the solid portions is noted after intravenous administration of gadolinium chelates.8 Ascites and peritoneal carcinomatosis are common associated findings that suggest malignancy. The diagnosis of Krukenberg tumour is all the more suggestive if a history of tumour of the digestive tract is already known.
Conclusion MRI is the imaging technique of choice in depicting any fibrous component within an ovarian mass. The spectrum of diagnoses to be considered in the presence of such a feature is rather reduced and depends mostly on the nature of the lesion and on associated clinical and key imaging data.
References 1. Siegelman ES, Outwater EK. Tissue characterization in the female pelvis by means of MR imaging. Radiology 1999;212:5e18. 2. Troiano RN, Lazzarini KM, Scoutt LM, et al. Fibroma and fibrothecoma of the ovary: MR imaging findings. Radiology 1997 Sep;204(3): 795e8. 3. Kitajima K, Kaji Y, Sugimura K. Usual and unusual MRI findings of ovarian fibroma: correlation with pathologic findings. Magn Reson Med Sci 2008;7:43e8. 4. Shinagare AB, Meylaerts LJ, Laury AR, et al. MRI features of ovarian fibroma and fibrothecoma with histopathologic correlation. AJR Am J Roentgenol 2012 Mar;198:W296e303. 5. Takahama J, Ascher SM, Hirohashi S, et al. Borderline Brenner tumor of the ovary: MRI findings. Abdom Imaging 2004;29:528e30. 6. Outwater EK, Siegelman ES, Kim B, et al. Ovarian Brenner tumors: MR imaging characteristics. Magn Reson Imaging 1998;16:1147e53. 7. Kato H, Kanematsu M, Furui T, et al. Ovarian mucinous cystadenoma coexisting with benign Brenner tumor: MR imaging findings. Abdom Imaging 2013;38:412e6. 8. Khashper A, Addley HC, Abourokbah N, et al. T2-hypointense adnexal lesions: an imaging algorithm. RadioGraphics 2012;32:1047e64. 9. Gui T, Cao D, Shen K, et al. A clinicopathological analysis of 40 cases of ovarian SertolieLeydig cell tumors. Gynecol Oncol 2012;127:384e9.
Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
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10. Shanbhogue AK, Shanbhogue DK, Prasad SR, et al. Clinical syndromes associated with ovarian neoplasms: a comprehensive review. RadioGraphics 2010;30:903e19. 11. Cho SM, Byun JY, Rha SE, et al. CT and MRI findings of cystadenofibromas of the ovary. Eur Radiol 2004;14:798e804. 12. Jung DC, Kim SH, Kim SH. MR imaging findings of ovarian cystadenofibroma and cystadenocarcinofibroma: clues for the differential diagnosis. Korean J Radiol 2006;7:199e204. 13. Tang YZ, Liyanage S, Narayanan P, et al. The MRI features of histologically proven ovarian cystadenofibromasdan assessment of the morphological and enhancement patterns. Eur Radiol 2013;23:48e56.
14. Rha SE, Oh SN, Jung SE, et al. Recurrent ovarian granulosa cell tumors: clinical and imaging features. Abdom Imaging 2008;33: 119e25. 15. Tanaka YO, Saida TS, Minami R, et al. MR findings of ovarian tumors with hormonal activity, with emphasis on tumors other than sex cordstromal tumors. Eur J Radiol 2007;62:317e27. 16. Kim SH, Kim SH. Granulosa cell tumor of the ovary: common findings and unusual appearances on CT and MR. J Comput Assist Tomogr 2002;26:756e61. 17. Ha HK, Baek SY, Kim SH, et al. Krukenberg’s tumor of the ovary: MR imaging features. AJR Am J Roentgenol 1995;164:1435e9.
Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
Contents lists available at SciVerse ScienceDirect
Clinical Radiology journal homepage: www.clinicalradiologyonline.net
Pictorial Review
Fibrous tumours of the ovary: Aetiologies and MRI features P.-F. Montoriol a, *, A. Mons a, D. Da Ines a, N. Bourdel b, L. Tixier c, J.M. Garcier a a
Department of Radiology and Medical Imaging, CHU Estaing, Clermont-Ferrand, France Department of Gynaecology, CHU Estaing, Clermont-Ferrand, France c Department of Pathology, CHU Estaing, Clermont-Ferrand, France b
art icl e i nformat ion Article history: Received 28 May 2013 Received in revised form 22 June 2013 Accepted 8 July 2013
The ovaries can be affected by a vast variety of tumours, which may be benign or malignant, solid or cystic. Although ultrasonography is often the first examination performed in the evaluation of gynaecological conditions, magnetic resonance imaging is nowadays the most accurate imaging technique in the characterization of ovarian masses. Once the ovarian origin of a pelvic mass has been determined, the detection of any fibrous component within the lesion significantly reduces the spectrum of aetiologies that should be considered. Fibrotic tissue usually displays marked low-signal intensity on T2-weighted sequences at MRI, and enhancement is mostly moderate after intravenous administration of gadolinium chelates. This review aims to provide the main diagnoses to consider at MRI whenever an ovarian tumour, both purely solid or solid and cystic, contains a fibrous component, even if minimally abundant. The corresponding key imaging features are provided. Ó 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.
Introduction Magnetic resonance imaging (MRI) is an accurate technique for the evaluation of ovarian masses. The standard imaging protocol usually includes T1-weighted sequences with and without fat saturation and T2-weighted sequences, the latter being mandatory in the exploration of the female pelvis due to its excellent soft-tissue contrast. A wide range of benign or malignant lesions that may contain different types of tissue may affect the ovaries. Among those, fibrous tissue represents low-cellularity material in combination with spindle, oval, or round cells that result in collagen formation. Fibrosis typically demonstrates
* Guarantor and correspondent: P.-F. Montoriol, CHU Estaing, Department of Radiology and Medical Imaging, 1 place Lucie et Raymond Aubrac, 63003 Clermont-Ferrand, France. Tel.: þ33 (0) 4 73 755 235. E-mail address: [email protected] (P.-F. Montoriol).
intermediate signal intensity on T1-weighted sequences and very low signal intensity on T2-weighted sequences.1 The enhancement after intravenous administration of gadolinium is variable, usually moderate. The differential diagnoses of marked T2-hypointense lesions at MRI mainly include blood products and calcifications, but the distinction is easily made using side-by-side analysis with T1 sequences: haemorrhagic cysts, especially endometrioma, may display moderate low signal intensity on T2-weighted sequences but high signal intensity on T1 images, whereas calcifications would show marked low signal intensity on both sequences. Once the ovarian origin of a pelvic mass is determined, it is important to identify any fibrous component, as the spectrum of diagnoses to consider is reduced. The aim of this review is to provide the aetiologies of fibrous ovarian lesions and the corresponding MRI features. All lesions presented in this article were surgically removed and histologically proven. The key findings of fibrous ovarian lesions are summarized in Table 1.
0009-9260/$ e see front matter Ó 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.crad.2013.07.005
Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
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Table 1 Summary of key findings of fibrous ovarian lesions. Ovarian lesion
Population
Nature
Potential associated clinical features
Relevant MRI findings
Fibroma/fibrothecoma
All ages
Solid
Brenner tumour
Pre-menopausal women Post-menopausal women All ages
Solid
Pleural effusion e ascites (DemonseMeigs’ syndrome) Usually asymptomatic
Solid
Virilization
Solid and cystic
Usually asymptomatic
Solid and cystic
Excessive oestrogen production (vaginal bleeding)
Homogeneous low signal on T2 images, weak enhancement Homogeneous low signal on T2 images, at least moderate enhancement Presence of lipid components, intense enhancement of non-fibrotic portions “Black sponge” aspect, dark-signal thickening of cysts’ wall Complex mass with haemorrhagic cysts, endometrial thickening, or polyps
Solid and cystic
Tumour of the gastrointestinal tract, carcinomatous ascites
At least moderate enhancement of solid components, peritoneal implants, ascites
Leydig cell tumour Cystadenofibroma Granulosa cell tumour
Krukenberg tumour
Middle-aged and post-menopausal women All ages
Figure 1 Ovarian fibroma. (a) Typical left ovarian fibroma (white arrow; U, uterine body) in a 78-year-old asymptomatic woman, presenting as a well-delineated mass with marked homogeneous low-signal intensity on the axial fast spin-echo (FSE) T2-weighted image. (b) The lesion displays isosignal on the axial fat-saturated T1-weighted image. (c) Enhancement after gadolinium administration is weak as seen on the axial fat-saturated image following gadolinium administration. Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
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Mainly solid fibrous ovarian masses Fibroma and fibrothecoma Fibroma and fibrothecoma are benign ovarian stromal neoplasms that belong to the sex cord stromal tumours category. They account for only 4% of all ovarian neoplasms, but represent the most common primary solid tumours in asymptomatic women of all ages.2 Small lesions are often an incidental finding; larger lesions may be a cause of pelvic discomfort. Pleural effusion or ascites may be present in the classic DemonseMeigs’ syndrome. There is a histopathological overlap between those entities, but the imaging features remain similar. Fibrothecoma may have either oestrogenic or androgenic activity, which explains why endometrial hyperplasia and polyps may be associated in some cases. Typically, at MRI examination, fibroma and fibrothecoma (Fig 1) present as well delineated ovarian masses and exhibit homogeneous low signal intensity on T2-weighted images3; large lesions may appear more heterogeneous on the same sequences due to oedematous or degenerative changes,4 with areas of high signal intensity. Haemorrhagic
e3
infarction or necrosis may occur in cases of torsion; however, even in those cases, areas of low-signal intensity on T2 images remain, usually allowing the differential diagnosis with malignant ovarian neoplasms,3 and therefore, avoiding unnecessary invasive surgery. On T1-weighted sequences, the lesions are usually iso or hypointense to uterine myometrium. Enhancement is weak after gadolinium administration, significantly inferior to that of myometrium or fibroids.4
Brenner tumour Brenner tumour, formerly known as “transitional cell tumour” because of its similarity to urothelial epithelium, is a usually benign and rather uncommon epithelial ovarian lesion that accounts for 1.5e2% of all ovarian neoplasms.5 They are more commonly discovered in premenopausal women6 and are often asymptomatic, as over 50% of tumours are <2 cm in size. Borderline and malignant forms are also described but are excessively rare.7 Histopathologically, benign Brenner tumours have solid or microcystic epithelial cell nests surrounded by dense fibrous stroma.5 As a result, they typically present as
Figure 2 Brenner tumour. Left ovarian Brenner tumour in a 52 year-old asymptomatic woman with a previous history of hysterectomy for postpartum haemorrhage. (a) Axial T2 image displays a large but homogeneous low-signal pelvic mass ( ), without any cystic or haemorrhagic changes. Axial fat-saturated T1-weighted images before (b) and after (c) gadolinium administration show significant enhancement of the lesion. This imaging feature is unlikely to be found in large ovarian fibromas. Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
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homogeneous low-signal ovarian masses on T2-weighted sequences. Calcifications may be seen within the mass but are often easier to depict on computed tomography images. Although the T2-weighted imaging findings of Brenner tumours overlap with those of fibrothecomas, Brenner tumours typically demonstrate at least moderate enhancement after contrast material administration (Fig 2), whereas fibrothecomas are typically hypovascular.8 Furthermore, unlike fibromas or fibrothecomas, large Brenner tumours tend not to display cystic or oedematous changes.6 Another imaging characteristic is the association with mucinous cystadenomas in up to 20% of cases, leading to a more complex, cystic and solid appearance,8 the latter component representing the Brenner tumour.
Leydig cell tumour Leydig cell tumours belong to the group of steroid cell tumours, which are very rare ovarian neoplasms accounting for less than 0.5% of all ovarian tumours.9 They are usually benign and predominantly seen in postmenopausal women. These lesions contain Leydig cells, lutein cells, and adrenocortical cells in various amounts together with a fibrous stroma and are often associated with a virilization syndrome.10 Most Leydig cell tumours present as small (<3 cm) and unilateral solid masses (Fig 3). Lipid components, which appear as areas of elevated signal on T1- and T2-weighted images, may be seen. However, the signal on T2 sequences
Figure 3 Leydig cell tumour. Right ovarian Leydig cell tumour (white arrow) in a 67-year-old woman presenting with hirsutism. (a) Coronal T2 image displays a small right ovarian mass (U, uterine body) with a peripheral low-signal fibrous component. The centre of the lesion shows a more cellular nature with elevated signal intensity and enhances strongly after gadolinium administration [(b) axial T1-weighted image and (c) axial T1-weighted contrast enhanced image]. Evocative clinical features are very useful to raise the diagnosis. Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
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is variable, depending on the extent of fibrous stroma. Intense enhancement of the non-fibrotic portions after intravenous administration of gadolinium is usually displayed.10
Fibrous and cystic ovarian masses Cystadenofibroma Cystadenofibromas are rare and usually benign epithelial ovarian lesions, accounting for about 1.7% of all ovarian neoplasms.11 They are often asymptomatic although large lesions may be a cause of pelvic pain or discomfort. No age
e5
prevalence is noted. Several histological subtypes (serous, mucinous, endometrioid, clear cell, or mixed) are described according to the epithelial component.8 All subtypes contain various amounts of fibrous stroma.12 Borderline variants are very rare and indistinguishable from benign lesions at MRI,13 but, because of this malignant potential, cystadenofibromas tend to be removed surgically. At MRI, the appearance of cystadenofibromas varies depending on whether the cystic or fibrous component predominates. They typically appear as a multiloculated cystic mass with a solid fibrous component (Fig 4) displaying the characteristic low-signal intensity on T2weighted sequences8 and a “black sponge” aspect.12 In predominantly cystic lesions, diffuse or partial thickening of
Figure 4 Cystadenofibromas. Large right ovarian benign mucinous cystadenofibroma in a 58-year-old woman complaining of chronic pelvic discomfort. (a) Axial T2-weighted image shows a voluminous complex right adnexal mass (U, uterine body) with numerous cysts of variable size and a solid fibrous stroma (long black arrows). Typical dark-signal thickening of a large cystic cavity is also visible (short black arrow). (b) A few cysts contain proteinaceous material that demonstrates a slightly elevated signal intensity on the axial fat-saturated T1-weighted image ( ). (c) Enhancement of the fibrous portions is almost non-existent on the axial fat-saturated T1-weighted image following gadolinium administration. Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
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the cystic wall with a T2-dark signal intensity is another suggestive MRI finding.12 Solid fibrous portions usually display moderate enhancement after gadolinium administration, inferior to that of the myometrium.13
Granulosa cell tumour Granulosa cell tumours (GCT) belong to the group of sex cordestromal tumours and represent 70% of all sex cordestromal tumours, but account for only 2e3% of all ovarian neoplasms.10 GCT is considered a low-grade malignancy but recurrence may be seen after surgical resection.14 Two distinct types are described: the juvenile type and the adult type, the latter being the far most common (95%), usually occurring in middle-aged and postmenopausal women.10 Excessive oestrogen production may cause related symptoms such as vaginal bleeding and endometrial hyperplasia.10
These are almost always (95% of cases) unilateral tumours that may present at imaging (Fig 5) as complex cystic masses or a combination of solid, fibrous portions, haemorrhage, and cystic components 10,15. A study16 showed that two common imaging findings were large multiseptate cystic masses and medium solid lesions with internal cysts; haemorrhage within the cysts was also a frequent MRI finding.14
Krukenberg tumour Krukenberg tumours are metastatic adenocarcinomas of the ovary and account for about 5e10% of all ovarian tumours.17 They mostly originate from the stomach (70% of cases), followed by the breast, colon, and appendix, and are bilateral in 60e80% of cases.8 The ovaries usually retain their shape, in contrast with the situation of primary ovarian neoplasms.17 They usually appear as solid masses with various amounts of cystic components (Fig 6) that may
Figure 5 Granulosa cell tumour. Large granulosa cell tumour in a 56-year-old patient presenting with metrorrhagia and suspicious pelvic mass seen at ultrasound. (a) Axial T2-weighted image shows a large solid and cystic mass that was found to originate from the right ovary. Thin fibrous portions can be seen within the lesion (white arrows). (b) Numerous cysts display typical haemorrhagic changes ( ) on the axial T1-weighted image. (c) Non-fibrotic portions enhance strongly after intravenous gadolinium administration on the axial contrast-enhanced T1-weighted image. Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005
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Figure 6 Krukenberg tumour. Unilateral Krukenberg tumour in a 70-year-old woman with a history of gastric adenocarcinoma recently discovered. A suspicious left adnexal mass was found at computed tomography. (a) Axial T2-weighted image displays a left ovarian mass with dark-signal fibrotic (white arrow) and neoplastic portions with a more elevated signal intensity ( ). Numerous peripheral cysts of variable size are seen. Moderate enhancement of the solid neoplastic component is seen after gadolinium injection on the (b) axial fat-saturated image and (c) axial fat-saturated contrast enhanced image. The absence of ascites or peritoneal implants makes the diagnosis difficult to establish without appropriate clinical data.
demonstrate elevated signal intensity on T1-weighted images due to mucinous filling or haemorrhagic changes. Then again, unlike primary ovarian cystadenocarcinoma, the solid component of Krukenberg tumours typically demonstrates a marked low signal on T2-weighted images, due to a dense stromal reaction.17 Moderate to marked enhancement of the solid portions is noted after intravenous administration of gadolinium chelates.8 Ascites and peritoneal carcinomatosis are common associated findings that suggest malignancy. The diagnosis of Krukenberg tumour is all the more suggestive if a history of tumour of the digestive tract is already known.
Conclusion MRI is the imaging technique of choice in depicting any fibrous component within an ovarian mass. The spectrum of diagnoses to be considered in the presence of such a feature is rather reduced and depends mostly on the nature of the lesion and on associated clinical and key imaging data.
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Please cite this article in press as: Montoriol P-F, et al., Fibrous tumours of the ovary: Aetiologies and MRI features, Clinical Radiology (2013), http://dx.doi.org/10.1016/j.crad.2013.07.005