Question

Classify Mullerian duct anomalies. Discuss the imaging approach in Mullerian duct anomalies, describing their imaging features briefly. [2+8]

Hint:

The ASRM classification of Müllerian anomalies is based on the degree of uterine duplication and presence of septum. MRI is the most accurate imaging modality for assessing these anomalies.

Answer 1

Step 1: Classification of Mullerian Duct Anomalies.
Müllerian duct anomalies (MDAs) result from abnormal development of the Müllerian ducts during embryogenesis. These anomalies lead to congenital uterine malformations, which can affect the uterus, cervix, and upper vagina. MDAs are classified into several categories based on the type of anomaly and the extent of the malformation. The American Society for Reproductive Medicine (ASRM) classification system for Müllerian anomalies includes the following categories: (1) Class I: Müllerian Agenesis/Hypoplasia (Mayer-Rokitansky-Küster-Hauser Syndrome) - Definition: Complete or partial agenesis or hypoplasia of the uterus and upper two-thirds of the vagina. The Müllerian ducts do not develop, leading to primary amenorrhea and an absent or underdeveloped uterus.
- Clinical Features: Amenorrhea with normal secondary sexual characteristics.
- Imaging: MRI shows absent uterus or small rudimentary uterine structures. (2) Class II: Unicornuate Uterus - Definition: A single uterine horn develops, often with a rudimentary horn on the opposite side, which may be non-communicating. It can be associated with renal anomalies.
- Clinical Features: Unilateral pelvic pain, recurrent miscarriage, or ectopic pregnancy.
- Imaging: MRI or hysterosalpingography (HSG) reveals a single uterine horn, and the contralateral horn may show a non-communicating rudimentary structure. (3) Class III: Uterus Didelphys - Definition: Complete duplication of the uterus, cervix, and sometimes the vagina, resulting in two separate uterine cavities.
- Clinical Features: Reproductive difficulties such as miscarriages or preterm labor.
- Imaging: MRI and ultrasound show two separate uterine horns and cervical duplication. The vagina may also be duplicated. (4) Class IV: Bicornuate Uterus - Definition: Partial or complete duplication of the uterus, resulting in two uterine horns that may be separated by a dividing septum. The cervix may be single or double.
- Clinical Features: Reproductive challenges, such as miscarriages and preterm labor.
- Imaging: MRI and HSG show two uterine horns with a single cervix. MRI is particularly useful for assessing the degree of separation of the uterine horns. (5) Class V: Septate Uterus - Definition: A single uterine cavity divided by a fibrous or muscular septum, which may vary in length and thickness. The external uterine contour is normal.
- Clinical Features: Recurrent miscarriage or preterm labor due to the abnormal uterine cavity.
- Imaging: HSG shows a normal external uterine contour with a septum dividing the uterine cavity. MRI provides better delineation of the septum and the uterine wall. (6) Class VI: Arcuate Uterus - Definition: A mild form of septate uterus, with a slight indentation at the top of the uterine fundus.
- Clinical Features: Typically asymptomatic or associated with mild reproductive issues.
- Imaging: HSG and MRI show a normal uterine cavity with a slight indentation at the fundus. (7) Class VII: Hypertrophic Uterus - Definition: This category involves uterine enlargement without a structural anomaly. It is usually due to fibroids or endometrial hyperplasia.
- Clinical Features: Symptoms of menorrhagia and pelvic discomfort.
- Imaging: Ultrasound and MRI show myometrial enlargement or fibroid masses.