{"paper_id":"d0e94028-0a86-45f6-b81e-c24580b9c949","body_text":"Müllerian anomalies have a wide spectrum of presentations, and the complete\ncategorization of these anomalies is therefore challenging. In recent decades,\nvarious professional societies have proposed classifications in order to identify\nthe best diagnostic approaches.\nThe prevalence of müllerian anomalies varies considerably depending on the\npopulation studied, being up to 25% among women with a history of infertility and\nspontaneous abortions ( 1 ) . Such anomalies are associated with a higher\nincidence of premature births, as well as with premature rupture of the fetal\nmembranes, fetal malpresentation, and perinatal mortality. The incidence of\npremature birth varies according to the type of anomaly, being higher in cases of\nuterus didelphys, whereas the risk of abortion is higher in women with a septate\nuterus ( 2 ) .\nIn this review of the literature, we compare the müllerian anomaly\nclassifications proposed by the American Fertility Society (AFS) in 1979 and\n1988 ( 3 , 4 )  with that proposed in 2021 by the American\nSociety for Reproductive Medicine (ASRM) and with that proposed by the European\nSociety of Human Reproduction and Embryology and the European Society for\nGynaecological Endoscopy (ESHRE/ESGE) in 2013 ( 5 ) . We highlight the advantages,\nlimitations, and clinical implications of each classification, in order to\ncontextualize their use in daily radiology practice.\n\nThe development of the female reproductive tract involves the differentiation of the\nmüllerian ducts, driven by the absence of anti-müllerian hormone and\nby the activity of estrogen, resulting in the formation of the uterus, fallopian\ntubes, cervix, and upper vagina ( 6 , 7 ) . This process occurs in three\nstages ( 8 ) : the formation/development of the ducts,\nfollowed by their separation; fusion of the lower portions to form the uterus,\ncervix, and upper vagina; and reabsorption of the uterine septum, creating a single\nuterine cavity. Müllerian anomalies occur due to failure in any of those\nstages and can therefore be anomalies of development, fusion or reabsorption, with\nvarious manifestations, including a unicornuate, bicornuate, or septate\nuterus ( 9 ) . Fusion and reabsorption anomalies can also\ngive rise to a longitudinal or transverse vaginal septum ( 2 , 10 ) .\n\nHysterosalpingography, which has been used for almost a century, is the oldest method\nof evaluating uterine malformations. Although it allows examination of the uterine\ncavity, cervical canal, and tubal patency, it does not reveal the external contour\nof the uterus or obstructing anomalies such as a non-communicating uterine horn; nor\ncan it identify extrauterine alterations, including those affecting the ovaries or\nurinary tract ( 8 ) . Two-dimensional ultrasonography, which is widely\navailable and affordable, has good (90-92%) sensitivity for detecting uterine\nanomalies and is an effective screening tool ( 11 ) ; it can be used in order to\nidentify cases of uterine agenesis and cavity duplication, provided that\nwell-defined imaging criteria are followed to reduce interobserver\nvariability ( 12 ) .\nThree-dimensional ultrasound and magnetic resonance imaging (MRI) both allow\nvolumetric acquisitions and generate images in any plane, enabling detailed analysis\nof the uterine cavity and its external contour, regardless of the position of the\nuterus in the pelvis. For diagnosing müllerian anomalies, MRI is considered\nthe gold standard, offering greater operator independence and ease in identifying\nother, concomitant anomalies. On MRI, it is possible to characterize the uterine\ncontour, tubal ostia, and cervical os, which allows an accurate diagnosis to be\nmade ( 13 ) . For complex cases, as well as for cases of\npatients with accompanying malformations, deep endometriosis, or a history of\nsurgery or trauma, MRI is indicated ( 2 ) .\n\nThe first classification of müllerian anomalies was proposed by a pathologist\nnamed Eduard Kaufmann and published by the obstetrician Julius Jarcho in\n1946 ( 14 ) , establishing an initial milestone for the\ndiagnosis of these conditions. Fast forward to 1988, and the AFS published its\ncomprehensive system, which structured the anomalies into seven distinct classes,\ndepending on the degree of development and fusion of the müllerian ducts\n( Figure 1 ). These classes included\neverything from müllerian agenesis to uteri exposed to\ndiethylstilbestrol.\nFigure 1 Schematic representation of the 1988 AFS classification of\nmüllerian anomalies.\nSchematic representation of the 1988 AFS classification of\nmüllerian anomalies.\nClass I:  Agenesis or hypoplasia, with specific subdivisions for\nvaginal, cervical, basal, tubal, or combined alterations.\nClass II:  Unicornuate uterus, with variants ranging from a\nrudimentary communicating horn to the complete absence of a contralateral\nhorn.\nClasses III to VII:  Ranging from didelphic to bicornuate, septate,\nand arcuate uteri, to exposure to teratogenic substances such as\ndiethylstilbestrol.\nThe 1988 AFS classification was valued for its simplicity and effectiveness in\ncorrelating anatomical forms with clinical prognoses for pregnancy\noutcomes ( 15 ) . However, because it was one of\nthe first initiatives to systematize the classification of müllerian\nanomalies, the use of the AFS classification had some limitations, mainly the\nsubjectivity inherent in the lack of well-defined diagnostic criteria; the\ndifficulty in categorizing anomalies involving the vagina and cervix; and the\nfact that complex anomalies were allowed to be classified in an individualized\nmanner, those classifications therefore being more dependent on the\nheterogeneous knowledge regarding the entity and the different lexicons of the\nprofessionals involved ( 6 ) .\nIn response to the limitations of the AFS classification, the ESHRE/ESGE\nintroduced a more detailed system in 2013 that not only addressed uterine\nanomalies but also included specific categories for cervical and vaginal\nanomalies, with the aim of eliminating the subjective diagnosis of the original\nAFS classification, as well as allowing differentiation between a septate uterus\nand other, similar conditions, regardless of the absolute morphometric\ncriteria.\nThe ESHRE/ESGE classification is based on the pelvic anatomy and divides the main\nclasses according to anatomical alterations derived from the same embryological\norigin, whereas the subclasses are divided on the basis of anatomical variations\nof the main classes. Cervical and vaginal anomalies are divided into\nsupplementary and independent subclasses ( 5 ) , as illustrated in  Figures 2  and  3 .\nFigure 2 Scheme available in the 2013 ESHRE/ESGE classification.\nScheme available in the 2013 ESHRE/ESGE classification.\nFigure 3 Schematic representation of the 2013 ESHRE/ESGE classification of\nuterine anomalies.\nSchematic representation of the 2013 ESHRE/ESGE classification of\nuterine anomalies.\nIn the ESHRE/ESGE classification, class U0 includes cases with a normal uterus,\ndefined by a straight or curved interostial line, with small fundal myometrial\ninvagination that does not exceed 50% of the uterine wall thickness. This\nclassification avoids the use of absolute numbers, because the authors believed\nthat uterine dimensions and uterine wall thickness can vary between patients.\nTherefore, they defined uterine deformity based on uterine anatomical\nproportions, such as uterine wall thickness.\nClass U1, or dysmorphic uterus, includes cases with a normal external uterine\ncontour but with an abnormal shape of the uterine cavity. Its subclasses are as\nfollows: U1a (T-shaped uterus), characterized by a narrow uterine cavity due to\nthickening of the lateral walls, with the majority corresponding to the uterine\nbody and a smaller portion corresponding to the cervix; U1b (infantile uterus),\ncharacterized by a narrow uterine cavity without thickening of the lateral\nwalls, with the majority corresponding to the cervix and a smaller portion\ncorresponding to the uterine body; and U1c, or “other”, which includes minor\ndeformities of the uterine cavity, including those with small invagination of\nthe basal myometrium, which represents less than 50% of the thickness of the\nuterine wall.\nClass U2, also known as a septate uterus, is an anomaly in which the uterine\ncavity presents myometrial or fibrous invagination from the uterine fundus,\ncurrently described as a septum, which exceeds 50% of the thickness of the\nuterine wall. It is divided into two subclasses, depending on the degree of\ndeformity of the uterine body: U2a, or a partial septate uterus, characterized\nby the presence of a septum that partially divides the uterine cavity, above the\nlevel of the internal cervical os; and U2b, or a complete septate uterus,\ncharacterized by the presence of a septum that completely divides the uterine\ncavity up to the level of the internal cervical os. Patients with a complete\nseptate uterus (a class U2b anomaly) might present cervical anomalies (such as a\nuterus with a septate cervix), with or without vaginal defects.\nClass U3, also known as a bicornuate uterus, presents as an abnormal contour of\nthe uterine fundus, with an indentation of the serosa in the midline that\nexceeds 50% of the thickness of the uterine wall. The indentation can partially\nor completely divide the uterine body, in some cases including the cervix,\nvagina, or both. Class U3 is divided into three subclasses: U3a (a partial\nbicornuate uterus), characterized by an indentation of the serosa that partially\ndivides the uterine body above the level of the cervix; U3b (a complete\nbicornuate uterus), characterized by an indentation of the serosa that\ncompletely divides the uterine body up to the level of the cervix; U3c (a\nseptate-bicornuate uterus), characterized by an additional absorption defect in\nwhich the thickness (depth) of the indentation of the uterine fundus exceeds\n150% of the thickness of the uterine wall.\nClass U4 (a unicornuate uterus) is an anomaly in which there is unilateral\ndevelopment of the uterus, with the contralateral portion being incompletely\nformed or absent. It is divided into two subclasses: U4a, characterized by a\nunicornuate uterus with a functional rudimentary cavity, which has a functional\ncontralateral horn that can be communicating or non-communicating; and U4b,\ncharacterized by a unicornuate uterus without a functional rudimentary cavity,\nwith a non-functioning contralateral uterine horn or with agenesis of this\ncontralateral portion.\nClass U5 (an aplastic uterus) is defined by the absence of any fully developed or\nunilateral uterine cavity. Aplastic uteri are divided into two subclasses: U5a,\nthose with a rudimentary (functional) cavity, characterized by the presence of a\nfunctional horn (bilateral or unilateral); and U5b, those without a rudimentary\n(functional) cavity, with uterine remnants or complete agenesis of the\nuterus.\nFinally, class U6 is reserved for cases not yet classified.\nThe ESHRE/ESGE classification also categorizes coexisting cervical and vaginal\nanomalies on a scale from 0 to 4 ( Figure\n2 ). The authors removed the term “arcuate uterus” from the\nclassification, because it was considered confusing and because it was pointed\nout that there was a need for clearer definitions. Therefore, it was decided\nthat the septate uterus classification should include only patients with midline\ninvagination of the basal myometrium that occupied 50% of the uterine wall\nthickness. A new subcategory under the general term “other” was added to class\nU1 (dysmorphic uterus), giving the opportunity to include all minor deformities\nof the endometrial cavity, including midline invaginations of the basal\nmyometrium occupying 50% of the uterine wall thickness, making it clear that\nfurther clinical research would be required in order to determine the clinical\nvalue of this variant ( 5 ) .\nChief among the limitations of using the ESHRE/ESGE classification is the\ncomplexity of its clinical applicability, because it depends on individual\nanalysis and the interpretation of anomalies can therefore vary among\nprofessionals. Ludwin et al. ( 15 )  compared the ESHRE/ESGE\n(European) classification with the AFS (American) classification and observed\nthat the application of the ESHRE/ESGE criteria can result in the overdiagnosis\nof septate uterus, with a significant, nearly threefold, increase in the\nfrequency of its recognition, probably related to the cutoff point used, leading\nto excessive and unnecessary treatments ( 15 ) .\nThe 1988 AFS and 2013 ESHRE/ESGE classifications differ mainly in objectivity and\ndetail.\nThe 1988 AFS classification is based on general anatomical descriptions and has\nbeen criticized for allowing subjectivity in the interpretation of\nmüllerian anomalies. The AFS classification is more conservative and\nfocused on specific uterine anomalies, whereas the ESHRE/ESGE classification\nintroduced clearer, more standardized criteria and broadened the scope to\ninclude other malformations of the genital tract, but at the potential cost of\noverdiagnosis and unnecessary interventions.\nThe wide range of müllerian anomalies, combined with the rarity of these\nconditions and the absence of universal objective criteria, continues to\ncomplicate their identification and treatment ( 6 ) . An ideal\nclassification would facilitate the identification of these anomalies, improve\ncommunication between health professionals, and consequently optimize the\nclinical care provided to affected women. In this context, the need to update\nand refine existing classifications led to the creation of a new classification\nby the ASRM in 2021.\nThe ASRM convened a multidisciplinary group, including members of the ASRM\nitself, the Society of Reproductive Surgeons, and the American Society of\nPediatric and Adolescent Gynecology, as well as radiologists specializing in the\nimaging of müllerian anomalies. The group conducted a comprehensive\nanalysis of the existing classifications, highlighting their merits and\ndeficiencies.\nThe multidisciplinary ASRM group identified the 1988 AFS classification as the\nmost practical and widely accepted because of its simplicity and visual\nclarity ( 4 ) . Despite its limited scope-it did not\ninclude all forms of anomalies, nor did it include cervical and vaginal\nabnormalities, which were described in addition to the predominant malformation\nof the uterus-the AFS classification was adopted as the basis for the new system\nThat was considered preferable to the development of a completely novel\nsystem.\nIn the 2021 ASRM classification, the AFS categories have been expanded to include\nthree new classes: longitudinal vaginal septum, transverse vaginal septum, and\ncomplex anomalies. The illustrations have been modernized to maintain ease of\nrecognition, while more precise diagnostic criteria have been established to\ndistinguish, in particular, between bicornuate and septate uteri ( Figures 4  and  5 , respectively). A consistent, understandable lexicon has also been\nestablished to facilitate communication. Different than in the AFS\nclassification, the anomaly categories are no longer numbered but are identified\nby descriptive terminology.\nFigure 4 Schematic representation of the 2021 ASRM classification.\nSchematic representation of the 2021 ASRM classification.\nFigure 5 Schematic representation of the 2021 ASRM classification.\nSchematic representation of the 2021 ASRM classification.\nThe 2021 ASRM classification is divided into nine main categories:\n• Müllerian agenesis (with or without unilateral or\nbilateral atrophic uterine remnants and with or without a functioning\nendometrium)\n• Cervical agenesis\n• Unicornuate uterus (with or without a contralateral rudimentary\nhemiuterus and with or without a functioning endometrium)\n• Didelphic uterus (two hemiuteri and a non-fused or duplicated\ncervix)\n• Bicornuate uterus (partially fused bodies due to indentation of\nthe serosa)\n• Septate uterus\n• Longitudinal vaginal septum\n• Transverse vaginal septum\n• Complex anomalies\nIn the 2021 ASRM classification, specific criteria have been defined to\ncategorize septate, arcuate, and bicornuate uteri. In comparison with the 2016\nASRM guidelines ( 7 ) , modifications were made for the septate\nuterus, now defined as a uterus with an endometrial septum (myometrial or\nfibrous invagination from the uterine fundus) that is more than 1 cm long,\nangled at less than 90°, and has a normal external contour of the uterine fundus\n( Figure 6 ). A septate uterus may also\npresent septation of the cervix, in which case it is referred to as a complete\nseptate uterus, characterized by a continuous or discontinuous division with the\nmyometrial or fibrous uterine septum, without circumferential\nstroma ( 6 ) .\nFigure 6 T2-weighted, volumetric, turbo spin-echo MRI scans showing how to\nmake a correct measurements of the myometrial or fibrous\ninvagination of the uterine fundus, by angle (A,C) and by distance\n(B,D-length in centimeters). The diagnoses were arcuate uterus (A,B)\nand partial septate uterus (C,D).\nT2-weighted, volumetric, turbo spin-echo MRI scans showing how to\nmake a correct measurements of the myometrial or fibrous\ninvagination of the uterine fundus, by angle (A,C) and by distance\n(B,D-length in centimeters). The diagnoses were arcuate uterus (A,B)\nand partial septate uterus (C,D).\nKauffman considered the arcuate uterus to be a variation of the bicornuate\nuterus ( 14 ) , rather than a differential diagnosis\nwithin the septate uterus spectrum ( 16 ) . However, it was\nmentioned at the time as a possible variation of normal, with undetermined\nclinical repercussions. After the term “arcuate uterus” was omitted from the\n2013 ESHRE/ESGE classification, it reappeared in the 2021 ASRM classification,\ndefined as a uterus with a myometrial septum of less than 1 cm, maintaining the\nnormal external contour of the uterine fundus. The authors stated that an\narcuate uterus is a clinically insignificant finding and is therefore considered\na variant of normality.\nIn the 2021 ASRM classification, the bicornuate uterus is defined as an\nindentation in the serosa (of the external contour) greater than 1 cm that can\nbe accompanied by duplication of the cervix, which may be partially fused (with\nstroma separating the cervical canals) or with two completely separate cervices\n(with independent stroma and myometrium). Some uteri may present adenomyosis or\nmore vascular or connective structures between the horns than myometrium, which\nin some rare cases creates uncertainty due to the adoption of a single criterion\nof the serosa to differentiate septate from bicornuate. Connective structures\nrefer to connective tissues that can be present between the uterine horns,\ncontributing to the morphology of the uterine cavity. Connective tissue is\ncomposed of an extracellular matrix rich in collagen and other structural\nproteins, in addition to cells such as fibroblasts and myofibroblasts. In the\ncontext of differentiating between a septate and bicornuate uterus, the\npredominance of connective tissue in the uterine fundus can make classification\ndifficult; if the area between the horns presents a predominance of connective\ntissue and reduced vascularization, it can resemble a fibrous septum.\nThe 2021 ASRM classification also allows cross-comparison between categories.\nThat can aid in the diagnosis and choice among therapeutic options for complex\nor controversial cases ( Figure 7 ). With\nthese changes, the 2021 ASRM classification serves the purpose of building on\nthe simplicity, strengths, and easy identification of the 1988 AFS\nclassification, while expanding and updating the system to include cervical and\nvaginal anomalies. It incorporates valuable ideological pillars, notably the\nchoice of description rather than numbering, which allows for more accurate and\nintuitive identification of anomalies. In addition, it is designed to encompass\ncomplex anomalies and different anatomical structures, which helps avoid\nunderdiagnosis, especially at centers that are less\nspecialized ( 6 ) .\nFigure 7 Hysterosalpingography (A) showing two uterine cavities (arrows).\nUltrasound (B) and three-dimensional ultrasound (C) showing a normal\nexternal uterine contour (arrowhead) and a septum with a depth\ngreater than 1.0 cm and an angle of less than 90°, with a septum\nthat does not extend beyond the internal cervical os (arrow).\nAccording to the 1988 AFS (original American) classification, this\nwould be classified as a partially septate uterus (subclass Vb).\nAccording to the 2013 ESHRE/ESGE (European) classification, this\nwould be a partially septate uterus (subclass U2a), characterized by\nthe presence of a septum partially dividing the uterine cavity above\nthe level of the internal cervical os, with a normal (class C0)\ncervix and a normal (class V0) vagina.\nHysterosalpingography (A) showing two uterine cavities (arrows).\nUltrasound (B) and three-dimensional ultrasound (C) showing a normal\nexternal uterine contour (arrowhead) and a septum with a depth\ngreater than 1.0 cm and an angle of less than 90°, with a septum\nthat does not extend beyond the internal cervical os (arrow).\nAccording to the 1988 AFS (original American) classification, this\nwould be classified as a partially septate uterus (subclass Vb).\nAccording to the 2013 ESHRE/ESGE (European) classification, this\nwould be a partially septate uterus (subclass U2a), characterized by\nthe presence of a septum partially dividing the uterine cavity above\nthe level of the internal cervical os, with a normal (class C0)\ncervix and a normal (class V0) vagina.\nIn order to facilitate the dissemination and understanding of the 2021\nclassification, the ASRM provides a highly complete and practical online tool\nfor the differential diagnosis of anomalies, which can be easily consulted on\nthe ASRM website. This interactive tool presents, on the main page for each\nclass, the descriptors that facilitate the identification of the malformation.\nIn addition, it includes many possible variations of each class, making the\nclassification and diagnosis process more accessible and detailed. The\npracticality of this online tool allows health care professionals to navigate\nintuitively, with standardized information that simplifies the analysis and\npromotes diagnostic accuracy. Thus, the 2021 ASRM classification also aims to\nraise awareness about the diversity of müllerian anomalies, standardizing\nterminology to facilitate communication between professionals and support\nresearch in scientific databases, improving the quality of records. Furthermore,\nit acts as an educational tool, providing online information on the\npresentation, diagnosis, and treatment of anomalies, being applicable for\nprofessionals of all levels, including students and residents, and promoting\nknowledge and the defense of patient rights.\n\nDespite the creation of well-defined diagnostic criteria, some authors argue that the\ncutoff values established in the 2021 ASRM classification appear to be arbitrary and\nnot supported by robust scientific evidence, mainly in relation to the definitions\nof the most common anomalies, including arcuate, septate, and bicornuate\nuteri ( 16 ) . Under certain circumstances, there can\neven be discrepancies between these criteria, resulting in a greater number of\ninconclusive diagnoses. For example, the classification does not cover cases in\nwhich the uterus presents an internal indentation angle of less than 90°, but with a\ndepth of less than 10 mm; similarly, an indentation depth greater than 10 mm\naccompanied by a wide angle places the situation once again in a gray area between\nthe definitions of arcuate uterus and septate uterus ( Figure 8 ). Another limitation consists of the reaffirmation of the broad\nspectrum of müllerian anomalies, suggesting that the current categories may\nnot encompass all existing variants, which indicates the need for future revisions\nand updates to accommodate new discoveries, to better understand them, and,\nconsequently, to better treat them.\nFigure 8 T2-weighted turbo spin-echo MRI scans, in the axial and coronal planes (A\nand B, respectively). Note the normal external uterine contour\n(arrowhead) and the septum with a depth greater than 1.0 cm and a septal\nangle of less than 90° (arrow), together with a septum that extends\nbeyond the internal cervical os and a longitudinal vaginal septum (arrow\nin B). According to the 1988 AFS (original American) classification, it\nwould be classified as a complete septate uterus (subclass Va).\nAccording to the 2013 ESHRE/ESGE (European) classification, it would be\nclassified as a complete septate uterus (subclass U2b), with a\nduplicated (class C2) cervix and a non-obstructing longitudinal (class\nV1) vaginal septum. According to the 2021 ASRM (latest American)\nclassification, it would be classified as a complete septate uterus with\na duplicated cervix and longitudinal vaginal septum.\nT2-weighted turbo spin-echo MRI scans, in the axial and coronal planes (A\nand B, respectively). Note the normal external uterine contour\n(arrowhead) and the septum with a depth greater than 1.0 cm and a septal\nangle of less than 90° (arrow), together with a septum that extends\nbeyond the internal cervical os and a longitudinal vaginal septum (arrow\nin B). According to the 1988 AFS (original American) classification, it\nwould be classified as a complete septate uterus (subclass Va).\nAccording to the 2013 ESHRE/ESGE (European) classification, it would be\nclassified as a complete septate uterus (subclass U2b), with a\nduplicated (class C2) cervix and a non-obstructing longitudinal (class\nV1) vaginal septum. According to the 2021 ASRM (latest American)\nclassification, it would be classified as a complete septate uterus with\na duplicated cervix and longitudinal vaginal septum.\nOne important contribution to the evolution of classifications over the years,\nmaintained in the most recent classification, is the concept of continuity in\ndevelopment. It also reflects something that is increasingly observed today, due to\nadvances in knowledge and imaging techniques, which is “noncompliance” with the rule\nof development in the caudocranial direction (fusion and reabsorption of structures\narising from the müllerian ducts), which might have resulted in\nunderdiagnoses, especially in relation to cervical and vaginal fusion anomalies.\nMost of the classes in the 2021 ASRM classification remain linked to the final\nanatomical structures of the genitourinary tract as the main criterion. Perhaps the\nembryological origin of the structures could be a better reference, so that\ndifferent structures could be in the same class. In cases reported in the current\nliterature, associated genitourinary anomalies are only partially evaluated, largely\nbecause of the diagnostic approach or flow.\nUse of the term “T-shaped uterus” led to underdiagnosis and was heavily criticized in\nthe European classification. A suggested alternative was the term “congenital”,\nwhich is more comprehensive and thus allows the inclusion of possible new diagnoses\nto be described in the literature. Likewise, the discussion on “accessory cavitated\nuterine malformations” gained more attention in the literature. This is a new\napproach to findings that can resemble focal adenomyosis but are somewhat outside\nthe scope of this review.\nThe 2021 ASRM classification maintains an easy-to-understand format and offers\nstandardized terminology ( Figure 9 ). With its\ncommon, accessible language, this classification is expected to facilitate the\nexecution of clinical studies, which are essential for the advancement of\nreproductive health research.\nFigure 9 Mayer-Rokitansky-Küster-Hauser syndrome. Sagittal T2-weighted\nturbo spin-echo MRI (A), transvaginal ultrasound (B), and\nthree-dimensional pelvic floor ultrasound (C), demonstrating agenesis of\nthe uterus, cervix, and vagina. Urethra (arrow in B) with a larger than\nusual caliber, where the gel was introduced. The arrowhead in B shows\nthe rectum. D: Axial T2-weighted MRI showing ovaries with a normal\nappearance (arrows). These findings were associated with right-sided\nrenal agenesis (image not available). According to the 1988 AFS\n(original American) classification, this case would be categorized as\ncombined agenesis (subclass Ie). According to the 2013 ESHRE/ESGE\n(European) classification, it would be categorized as uterine agenesis\nwithout a rudimentary horn (subclass U5b), with cervical and vaginal\nagenesis (classes C4 and V4, respectively). According to the 2021 ASRM\n(latest American) classification, it would be classified simply as\nmüllerian agenesis.\nMayer-Rokitansky-Küster-Hauser syndrome. Sagittal T2-weighted\nturbo spin-echo MRI (A), transvaginal ultrasound (B), and\nthree-dimensional pelvic floor ultrasound (C), demonstrating agenesis of\nthe uterus, cervix, and vagina. Urethra (arrow in B) with a larger than\nusual caliber, where the gel was introduced. The arrowhead in B shows\nthe rectum. D: Axial T2-weighted MRI showing ovaries with a normal\nappearance (arrows). These findings were associated with right-sided\nrenal agenesis (image not available). According to the 1988 AFS\n(original American) classification, this case would be categorized as\ncombined agenesis (subclass Ie). According to the 2013 ESHRE/ESGE\n(European) classification, it would be categorized as uterine agenesis\nwithout a rudimentary horn (subclass U5b), with cervical and vaginal\nagenesis (classes C4 and V4, respectively). According to the 2021 ASRM\n(latest American) classification, it would be classified simply as\nmüllerian agenesis.\n\nThe evolution of the classification of müllerian anomalies reflects an ongoing\neffort to improve the diagnostic accuracy and clinical management of these complex\nconditions. The transition from the AFS classification to the European\nclassification to the more recent ASRM classification, exemplifies the progress in\nour understanding of the anatomical variations of the female reproductive tract and\nthe need for more detailed and less subjective diagnostic approaches. Radiologists\nperforming investigational examinations for uterine malformations must be aware of\nthe benefits of each classification in order to appropriately classify the findings,\nunderstanding that there are variables in the classifications and that it is\nnecessary to facilitate the diagnosis in order to guide the referring physician in\nfinding the best course of action to follow.\nThe 2021 ASRM classification not only expanded diagnostic categories but also\nfacilitated a clearer common language for health care professionals. This\nadvancement is vital to improving reproductive outcomes and quality of life for\npatients affected by these anomalies. Finally, the flexibility of the new\nclassification to incorporate future discoveries highlights the importance of\nongoing review, ensuring that the classification of müllerian anomalies\nremains relevant and applicable to scientific and clinical advances.","source_license":"CC-BY-4.0","license_restricted":false}