EAC Classification Of Congenital Malformations Of The Female Genital Tract

Author Information

Parulekar SV

(Professor and Head Department of Obstetrics and Gynecology, Seth GS Medical College & KEM Hospital, Mumbai, India)

Abstract

Congenital malformations of the female genital tract are deviations from the normal anatomy that occur due to aberrations during development. They can occur singly, in combinations, and even as a part of syndromes. There are a large number of classifications by different workers, aiming at providing comprehensive, simple, and easy to use system. All existing systems have pros and cons, and none appears to be perfect. A new classification is presented here. It is called EAC classification, because it is based on a combination of embryological aberration, anatomical abnormalities and clinical features.

Introduction

Congenital malformations of the female genital tract are diverse. Some women have combinations of different malformations. Some of them are diagnosed at the time of birth, while most of them are diagnosed much later, during adolescence or in the reproductive age. These anomalies have varied effects on the patient's life, including amenorrhea, cryptomenorrhea, dysmenorrhea, dyspareunia, repeated pregnancy wastage, infertility, intraperitoneal hemorrhage due to rupture of a gravid horn of the uterus, and pelvic masses. These conditions can be explained very well by the underlying embryological deviations. Treatment of some of them is satisfactory, while others have no treatment. Contrary to popular belief, a number of patients with some of these anomalies go through their lives without any health problems, and these conditions are discovered coincidentally when a laparotomy or laparoscopy is done for some unrelated indication. Endoscopic surgery has made treatment of some of these conditions less invasive, but not necessarily more satisfactory. Some of these conditions are associated with congenital anomalies of the urinary system and the skeletal system. Sometimes the anomalies of the genital tract come to light when a patient is being evaluated for the urinary or skeletal system abnormalities.

Congenital malformations of the female genital tract have been known from as early as 300 BC. The first case of agenesis of uterus and vagina was documented by Columbo in the 16th century. The prevalence of these malformations is reported to be 0.1-4.3%.^[1,2,3,4,5] The female genital tract develops from the mullerian ducts and urogenital sinus, which are developmentally interconnected though they originate from different germ layers. Each mullerian duct has upper two-third developing into the fallopian tube of the respective side, while the lower one-third fuses with that of the opposite side to form the uterus, cervix and upper vagina. The lower and mid vagina develop from the urogenital sinus. Adjacent walls of the mullerian ducts have to break down after their fusion to form a single cavity of the uterus, cervix and vagina. Any dysregulation  or interruption in this process can result in anomalies like agenesis, hypoplasia, duplication, absence of functioning mucosa, and obstruction to outflow tract. It was believed that fusion of the mullerian ducts occurs in a craniocaudal direction. However it is now believed to occur in a segmental and bidirectional manner. That would explain occurrence of certain anomalies of duplication and septation which could not be explained before. The mesonephric ducts are closely related, and hence anomalies of the urinary system tend to be associated with anomalies of the mullerian ducts. Any disruption of adjacent mesoderm results in associated skeletal anomalies. The caudal portion of the celomic cavity becomes the cloaca. It divides into the rectum dorsally and the urogenital sinus ventrally. The caudal portion of the fused mullerian ducts fuses with the urogenital sinus to form the mullerian tubercle. A solid epithelial cord grows between the tubular portion of the mullerian duct and the mullerian tubercle, to form the vagina. However there is another school of thought that it forms from the mesonephric ducts and mullerian tubercle, so that a mesonephric abnormality will cause a uterine anomaly, a vaginal anomaly, and agenesis of the ipsilateral kidney.^[6] The hymen forms at the junction of the urogenital sinus and the vagina from the endodermal membrane which differentiates into the vaginal vestibule. It usually ruptures perinatally.

There are a number of classification systems for congenital malformations of the female genital tract. Jones’ classification was the most basic and widely used one.^[7] It divided the anomalies into three groups: agenesis, lateral fusion defects (obstructive and non-obstructive or symmetrical and asymmetrical), and vertical canalization defects (obstructive and non-obstructive). It was quite satisfactory. Still a number of other classification systems were described, perhaps in search of perfection. Buttram et al described another classification, in order to introduce greater clarity and uniformity, dividing the anomalies into groups with similar clinical manifestations, treatment, and prognosis of pregnancy outcome.^[8,9] It was similar to the classifications by Jarcho and by Fenton and Singh.^[10,11] It was modified a little by the American Fertility Society - AFS (now called American Society for Reproductive Medicine – ASRM).^[12] AFS complicated matters further by describing two classifications – one called ‘American Fertility Society Classification of Mullerian Anomalies’ and the other called ‘American Fertility Society Classification of Uterovaginal Anomalies’. Misleading terminology was used, such as ‘vertical fusion of mullerian ducts’, when the mullerian ducts were not segmented entities which could fuse vertically. These classifications were quite complicated, had a significant degree of overlap in different groups, missed out some anomalies (those of the fallopian tubes, cervix, vagina, ovaries and urinary system), did not cover cases which had more than one anomaly (complex anomalies), and the claim of grouping the anomalies based on similar clinical manifestations, treatment, and prognosis of pregnancy outcome could not be substantiated. For example, AFS  classification grouped hypoplasia and/or dysgenesis of the vagina, cervix, uterus and/or adnexae together, which does not have any functional and prognostic significance. This signified the need for a newer and better classification system.^[13] Semmens proposed a classification based on the functional aspects, like the potential capacity of the uterus.^[14] It did not gain wide acceptance. Oppelt et al proposed a classification based on the morphological and anatomical features of the Vagina, Cervix, Uterus, Adnexa, and Associated Malformation (VCUAM).^[15] This classification system was comprehensive, but was criticized to be complex and requiring referral to the chart for interpretation of the class given to a patient. It was also said to be not suggestive of the origin or the pathogenic mechanism of the malformations. These criticisms were not very valid, as complexity of a classification of a wide range of anomalies was likely to be complex, and referring to a chart was actually better as it avoided errors. The pathogenesis of any malformation did not have to be suggested by the classification, as the aim of the classification was to categorize the anomalies, so that appropriate treatment could be planned and prognosis determined, which had nothing to do with the pathogenesis. However the classification did not cover some complex anomalies. Acién's embryological and clinical classification was developed based on the hypothesis that there were four locations for the origin of these malformations.^[16,17] Based on that five groups of malformations were made - agenesis of an entire urogenital ridge, mesonephric anomalies, mullerian anomalies, cloacal anomalies and combinations of these malformations. It was stated that it was necessary to have a correct understanding of the embryologic aspects of the anomalies in the classification so as to be able to plan the treatment correctly. This was not felt to be so by many clinicians. It was also quite complex to be used routinely by a clinician. Hence this classification did not gain much popularity. The  European  Society  of  Human  Reproduction  and  Embryology (ESHRE)  and  the  European  Society  for  Gynaecological  Endoscopy (ESGE), established a common working group under the name CONUTA. This group developed the ESHRE/ESGE classification system based on the anatomy  of the anomalies.^[18] This classification had main classes based on the deviations of uterine anatomy derived from the same embryological origin, arranged in ascending order of severity. The subclasses were based on the anatomical  variations  of  the  main  classes  expressing  different degrees of uterine deformity and being clinically significant. Cervical and vaginal anomalies were classified in independent supplementary subclasses. Though it was claimed that an extremely detailed subclassification was avoided for the sake of simplicity, it was still a quite complex classification. Including the uterine anomalies in the main class and cervical and vaginal anomalies in coexistent subclass seemed arbitrary and without any rational basis for the same. It required referring to a chart for interpretation of the class assigned to a patient. It did not cover complex anomalies, anomalies of the cloaca and urogenital sinus, and associated anomalies. It also included a class in which to put all anomalies that did not fit in the classification system, which was admitting that it was an incomplete classification system.

Classification

EAC Classification of Congenital Malformations of Female Genital Tract

Organ	Single	Right (Specify length in cm)	Left (Specify length in cm)	Degree of Resorption of Adjoining walls (%)	Remarks
Fallopian tube	NA	FaR1	FaL1	NA
		FaR2	FaL2
		FaR3	FaL3
		FaR4	FaL4
		FaR5	FaL5
Uterus (corpus)	Ut1 __cm Fn/No Fn Obst/NoObst	UtR1 __cm Fn/No Fn Obst/NoObst	UtL1__cm Fn/No Fn Obst/NoObst
	Ut2 __cm Fn/No Fn Obst/NoObst	UtR2 __cm Fn/No Fn Obst/NoObst	UtL2__cm Fn/No Fn Obst/NoObst
Uterus (Cervix)	Cx1__cm Fn/No Fn Obst/NoObst	CxR1__cm Fn/No Fn Obst/NoObst	CxL1__cm Fn/No Fn Obst/NoObst
	Cx2__cm Fn/No Fn Obst/NoObst	CxR2__cm Fn/No Fn Obst/NoObst	CxL2__cm Fn/No Fn Obst/NoObst
Vagina	Vg1__cm Fn/No Fn Obst/NoObst	VgR1__cm Fn/No Fn Obst/NoObst	VgL1__cm Fn/No Fn Obst/NoObst
	Vg2__cm Fn/No Fn Obst/NoObst	VgR2__cm Fn/No Fn Obst/NoObst	VgL2__cm Fn/No Fn Obst/NoObst
Hymen	Hy	HyR	HyL	NA
Clitoris	Cl	ClR	ClL	NA
Labium majus	NA	LMjR	LMjL	NA
Labium minus	NA	LMiR	LMiL	NA
Introitus	In	InR	InL
Cloaca	Clo-S
	Clo-L
	RVF
	RVeF
Urogenital sinus	UGS
	VVF
Renal anomalies
Skeletal anomalies
Other anomalies
Mesonephric duct remnant	MDR-Ep
	MDR-Pa
	MDR-Ga
Syndrome
Source of information	Clinical examination / Ultrasonography / Computerized tomography / Magnetic resonance imaging / Hysterosalpingography / Hysteroscopy / Laparoscopy / Laparotomy / Dilatation and Curettage

Key

(NA: Not applicable; Fa: Fallopian tube, FaR: Right fallopian tube, FaL: Left fallopian tube, 1: Fimbriae, 2: Infundibulum, 3: Ampulla, 4: Isthmus, 5: Interstitial part; Ut: Uterus, Ut1: Uterus above isthmus, Ut2: Isthmus of uterus, UtR: Right horn of uterus, UtL: Left horn of uterus, UtR1: Right horn of uterus above isthmus, UtR2: Isthmus of right horn of uterus, UtL: Left horn of uterus, UtL1: Left horn of uterus above isthmus, UtL2: Isthmus of left horn of uterus; Cx: Cervix, Cx1: Supravaginal cervix, Cx2: Vaginal part of cervix, CxR1: Supravaginal right cervix, CxR2: Vaginal part of right cervix, CxL1: Supravaginal left cervix, CxL2: Vaginal part of left cervix; Fn/No Fn: Functional [with functional mucosa] or Nonfunctional [without functional mucosa] – applicable part to be encircled; Obst: Obstruction, NoObst: No obstruction or patent; Hy: Hymen, HyR: Right hymen (in case of duplication of vulva), HyL: Left hymen (in case of duplication of vulva); Cl: Clitoris, ClR: Right clitoris (in case of duplication of vulva or ectopia vesicae), ClL: Left clitoris (in case of duplication of vulva or ectopia vesicae); LMjR: Right labium majus, LMjL: Left labium majus; LMiR: Right labium minus, LMiL: Left labium minus; Clo: Cloaca, Clo-S: Cloaca with short common channel (< 3 cm), Clo-L: Cloaca with long common channel (> 3 cm), RVF: Rectovaginal fistula, RVeF: Rectovestibular fistula; UGS: Urogenital sinus - Two external openings (of UGS and anus), VVF: Vesicovaginal fistula; MDR: Mesonephric duct remnant, MDR-Ep: Epoophoron cyst, MDR-Pa: Paroophoron cyst, MDR-Ga: Gartner’s duct cyst).

Notes

1. The length of concerned part should be specified in centimetres.
2. Distinction is not made between atresia of cervix and presence of cervix in the form of a fibrous band, fragments, and some lumen in a small part.
3. Degree of resorption of adjacent walls (degree of lateral fusion) is indicated as a percentage of the total length, as in case of a longitudinal septum in the uterus or vagina, and degree of separation of the two horns.
4. If a particular organ is not mentioned, then it is normal, e.g. if only two horns of the uterus are mentioned and the cervix is not mentioned, then the cervix is single and normal.
5. The column on ‘remarks’ is for making entries not covered in the previous part, such as shape of the uterine cavity (T-shaped, arcuate), thickness of a septum, location of rudimentary horns etc. These entries are made in the chart and also in parentheses at the end of the final class.
6. Malformations present in a given patient are charted, and then written in sequence with dashes in between.
7. Any complications are written in the column on remarks, and in parentheses at the end of the final class, e.g. pelvic endometriosis.
8. A number of syndromes are associated with malformations of the female genital tract. If a syndrome is diagnosed, it is stated in a separate row.
9. The sources of diagnostic information are listed in one row. Dilatation and curettage is included, as a septum or two uterine horns can be felt by a uterine sound and a curette. The sources applicable in a given patient are encircled.

Examples

1. UtR 6 cm Fn NoObst: Right unicornuate uterus measuring 6 cm in length with functioning endometrium and communicating with cervix (no outflow tract obstruction).
2. UtR 3 cm Fn NoObst – UtL 7 cm Fn Obst - 70%: Bicornuate uterus, with 3 cm long functional, communicating right horn and 7 cm long functional noncommunicating left horn with hematometra, and upper 70% uterus is in the form of two horns, while lower 30% is single. (Note: a functioning horn produces menstrual blood, which collects in the horn due to outflow tract obstruction, producing hematometra. Presence of hematometra is not mentioned separately, as it is implied from the classification.)
3. UtR 6 cm Fn NoObst – UtL 5 cm Fn NoObst – VgR 9 cm Fn NoObst – VgL Fn Obst – (hematometra, hematosalpinx): Bicornuate uterus with right functional horn opening in right patent vagina, and left functional horn opening in left obstructed vagina (left hematocolpos is not entered, as it is always present in such a situation. Hematometra and hematosalpinx need to be mentioned in the column on remarks, as they develop later, and may not be present in all cases).

Discussion

A classification has to be comprehensive, accurate in definition of abnormal anatomy and pathology, unambiguous, simple to use and interpret. Contrary to popular belief, it need not group patients based on the underlying embryological aberration,  treatment and prognosis. This is so because a clinician has to know the treatment and prognosis of a given condition irrespective of its class in any classification system, and none of these three factors affects the treatment and prognosis. The purpose of the classification is to permit uniform categorization of any anomaly anywhere in the world, so that different people understand what other workers are talking about and meta analysis of data from multiple studies becomes easier.

The proposed EAC classification is a combination of aberration of embryological process, anatomy, and clinical features. The malformations are arranged in sequential order in a craniocaudal direction, starting with the fallopian tube. This step avoids giving one organ greater importance over others, when the aim is to cover all organs and all malformations. Creation of classes with names I, II, … or A, B, … is avoided, because it is neither easy to remember which class relates to which malformation, nor necessary. Short forms are used for organs, the way a clinician does when writing clinical notes. This makes the task of applying this classification to the cases encountered not much different from what was being done before. It also avoids confusion between classes and minimizes errors. The side of the anomaly is indicated by R and L for right and left side. When there are parts of an organ, one or more of which can be anomalous, numbers are used to indicate the part(s) involved, e.g. Ut1 and Ut2 for uterine corpus above isthmus and isthmus respectively. These classes can be remembered easily by a clinician, and there will be minimal need to refer to the chart, except during the learning phase. When there is a complex anomaly comprising of a combination of two or more anomalies involving different parts of the genital tract, the final class is written as a combination of the anomalies in sequence, with dashes in between. A chart is also filled, so as to maintain a record, along with a diagram (or digital image). The chart is in a tabular form, to make it compact and easy to follow. Precision is used in description of the degree of the abnormality, such as length of uterus in case of hypoplasia, length of uterine septum as a percentage of the total uterine length, bifurcation of the uterus (in case of a uterine fusion defect) as a percentage of the total uterine length, and length of a vaginal septum as a percentage of the total vaginal length. This degree of precision is possible with modern methods of evaluation, such as ultrasonography, computerized tomography and magnetic resonance imaging. Associated anomalies of other organs and systems are listed in the same table, and if the anomalies are a part of any syndrome, it is mentioned too. The last column of the table is for remarks, for adding information that cannot be put in the classification, but needs to be included, e.g. thickness of a uterine septum, shape of a uterine cavity, location of a perforation in a transverse vaginal septum, and presence of a complication like endometriosis. Statement of the source of the information (mode of imaging, endoscopy and laparotomy) at the bottom of the table underlines the degree of accuracy of the classification.

The classification can be stored in digital form as a document or a web form too. That would be useful for transmission of the information to another consultant elsewhere. It would also make analysis of a large amount of data convenient.

Conclusion

EAC classification is a comprehensive classification of congenital malformations of the female genital tract that is based on embryological aberration, anatomical defects and clinical features. It has mathematical precision which is not found in any classifications before. It includes associated anomalies of other systems and organs, syndromes, and complications. It uses terminology that clinicians are familiar with, so that the learning curve is small, interpretation can be without having to refer to charts, and user satisfaction would be high.

References

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Citation

Parulekar SV. Classification Of Congenital Malformations Of The Female Genital Tract. JPGO 2015. Volume 2 No. 4, Available from: http://www.jpgo.org/2015/04/eac-classification-of-congenital.html