Intramural uterine leiomyoma is the most common type of uterine leiomyoma in terms of location. They are centred primarily within the myometrium. A large intramural uterine leiomyoma can, however, have a submucosal or subserosal component.
They are usually asymptomatic; h...
The presence of intrauterine air can sometimes be inferred by tiny internal echoes on ultrasound or foci of very low attenuation at computed tomography (CT). The term encompasses air within the uterine cavity as well as intramyometrial air.
It can arise from a number of situations
Intrauterine blood clot can result from a number of situations in gravid, non-gravid and postpartum states. It can mimic many other pathologies.
Any condition that predisposes to an intrauterine haemorrhage can potentially result in an intrauterine blood clot.
Intra-uterine contraceptive devices (IUCD) are one of the most frequently used methods of contraception throughout the world. It prevents pregnancy by:
thinning the endometrial lining
preventing sperm motility
There are two main types of IUCDs:
non-hormonal metallic ...
Intravenous leiomyomatosis (IVLM) is characterised by the extension into venous channels of histologically benign smooth muscle tumour arising from either the wall of a vessel or from a uterine leiomyoma.
Intravenous leiomyomatosis should not be confused with benign metastasising leiomyoma, in ...
In utero bowel perforation results in a chemical peritonitis (meconium peritonitis) from peritoneal leakage of sterile meconium.
It can result from many causes which include:
in utero intestinal ischaemia
Invasive mole is a tumorous growth associated with gestation and falls under the spectrum of gestational trophoblastic disease. Due to their aggressive growth characteristics, invasive moles are considered locally invasive non-metastasising neoplasms.
An invasive mole develops in ...
The International Ovarian Tumour Analysis (IOTA) group ultrasound rules for ovarian masses are a simple set of ultrasound findings that classify ovarian masses into benign, malignant or inconclusive masses. These rules apply to masses that are not a classical ovarian mass (e.g. corpus luteum, en...
An irregular yolk sac or an abnormally shaped yolk sac is an imaging feature that can be observed in early pregnancy scanning. It may be seen in up to 17% of early pregnancy scans 1. In contrast to an irregular gestational sac, the observation of an irregular yolk sac in not thought to correlate...
An isolated cleft palate is a type of facial cleft. This is a much rarer occurrence than a cleft lip +/- palate and is thought to represent a different pathological entity.
The estimated incidence is at ~1 per 2000-2500 pregnancies 4-5. There may be a slight female predilection 4....
An isthmic ectopic pregnancy is a sub type of tubal ectopic pregnancy an accounts for ~ 12% of such cases. According to one study the rate of tubal wall disruption was higher than with an ampullary ectopic pregnancy, suggesting that in an isthmic ectopic pregnancy, the trophoblast penetrates the...
IUCD related uterine perforations are one of the causes of uterine perforation. It is rare, but a serious complication of an IUCD insertion, and is often clinically silent.
The incidence rate is reported at ~2 in 1000 2.
Perforation at the time of insertio...
Juberg-Hayward syndrome (JHS), also known as the oro-cranio-digital syndrome, is a rare autosomal recessive syndrome characterised by the association of the following:
cleft lip and palate
minor vertebral and rib anomalies 4
horseshoe kidneys 4
Junctional zone is a region representing the inner myometrium and is a very important imaging feature in pelvic MR imaging for interpretation of various pathologies. In its intact state, it is usually visualised as a low T2 signal layer beneath the endometrium.
This low signal intensity is thou...
Juvenile granulosa cell tumours of the ovary (JGCT) are a less common subtype of granulosa cell tumour of the ovary (~5% of cases). They are classified as ovarian sex cord / stromal tumours.
It typically occurs in premenarchal girls and young women. The mean age of presentation is...
Klinefelter syndrome (KS) is a chromosomal anomaly, which in most cases is characterised by 47 chromosomes instead of the usual 46.
The estimated incidence is 0.15-0.2% of live births.
the testes are normal prior to puberty and small in post pubertal testes...
Krukenberg tumour, also known as carcinoma mucocellulare, refers to the "signet ring" subtype of metastatic tumour to the ovary. The colon and stomach are the most common primary tumours to result in ovarian metastases, followed by the breast, lung, and contralateral ovary.
The labia majora (singular: labium majus) form the anteroinferior most part of the vulva, they are continuous with the mons pubis anteriorly and the perineum posteriorly. The labia are apposed in the midline forming the, externally-visible, pudendal cleft.
The labia majora have a...
A large for date uterus is a clinical observation based on uterine fundal height, which may result in referral for ultrasound assessment, usually in mid to late pregnancy.
constitutionally large fetus
Large loop excision of the transformation zone (LLETZ) is a gynaecological procedure. It is currently one of the most commonly used approaches to treat high grade cervical dysplasia - cervical intraepithelial neoplasia.
Leiomyomas of the uterine cervix are an unusual variation in terms of location for a uterine leiomyoma.
They are rare and account for ~5% (range 0.6-10%) of uterine leiomyomas 1,4.
Clinical symptoms of cervical leiomyomas, including hypermenorrhea, dysmenor...
Lethal multiple pterygium syndrome (LMPS) is a lethal sub type of the multiple pterygium syndrome.
It is primarily characterised by the presence of pterygia (or wings) present in two or more body areas overlying predominantly the large joints. Accompanying joint contractures are almo...
The levator ani, also known as the muscular pelvic diaphragm, is the musculotendinous sheet that forms the majority of the pelvic floor, supports the pelvic viscera, and aids in urinary and faecal evacuation as well as maintaining continence.
The levator ani has three main compon...
A longitudinal vaginal septum is a congenital abnormality of the vagina where a septum divides it into two parallel cavities.
Usually asymptomatic unless obstructed and if obstructed it may cause cyclic pelvic pain. Amenorrhoea may occur if both cavities are obstructed 1....
A long philtrum is a clinical or imaging observation where the philtrum (middle part of the upper lip) is longer than normal.
It can be associated with a number of anomalies which include
Cornelia de Lange syndrome
A long umbilical cord has been variably defined. Considering the mean length of the umbilical cord at ~50-70 cm 1, a long cord in absolute terms is usually taken as one that is over 70 cm in length at term 1-3.
increased incidence of umbilical cord knots
increased incidence of ...
Lower vaginal atresia is a type of vagina atresia where the the lower 3rd of the vagina fails to develop.
Patients may present with primary amenorrhoea with progressive cyclical abdominal pain.
It is usually not considered a type of Mullerian duct anomaly. It ...
Lowe syndrome (also known as the the oculocerebrorenal syndrome of Lowe) is a multi-system disorder characterised by anomalies primarily affecting the eyes, nervous system, and kidneys.
It is an extremely rare, pan-ethnic, x-linked disease, with estimated prevalence in the general po...
Low-lying placenta occurs when the placenta extends into the lower uterine segment and its edge lies too close to the internal os of the cervix, without covering it. The term is usually applied when the placental edge is within 0.5-5.0 cm of the internal cervical os 1. Some alternatively give th...
Low set ears is a descriptive term used to given a depressed or abnormally low positioning of the pinna by two or more standard deviations below the population average.
Low set ears can be associated with a number of anomalies which include
aneuploidic / chromosomal sy...
Lymphoma of the uterine cervix is generally uncommon and when it does occur tends to present as cervical involvement with added background multi-organ disease rather than isolated primary cervical lymphoma 1. It is often considered part of the spectrum of uterine lymphoma.
In the ...
Macroglossia means an enlarged tongue. It may be absolute (greater than the 95th centile) or relative (enlarged compared with oral cavity).
Recognised associations include:
tends to be a relative macroglossia
may also have intermi...
Male pseudohermaphroditism (MPH) is a variation of gender development.
Patients with male pseudohermaphroditism have 46 XY karyotype and may manifest as a female phenotype with various degrees of undervirilization secondary to partial androgen insensitivity.
A malignant mixed germ cell tumour of the ovary is a subtype of ovarian germ cell tumour. These are not to be confused with malignant mixed Müllerian tumours of the ovary.
These tumours are rare. They most commonly affect adolescent women of reproductive age 1.
Malignant mixed Mullerian tumours (MMMTs), sometimes referred to as a carcinosarcoma, are uncommon malignancies that can occur anywhere along the female genital tract.
It is comprised of both epithelial (carcinomatous) and stromal (sarcomatous) components.
Implicated risk factors in...
Malignant mixed Mullerian tumours (MMMT) of the ovary, also known as carcinosarcoma of the ovary, are a rare type of mixed ovarian tumour with both epithelial and stromal components.
They are very rare and account for less than 1% of all ovarian cancers. Most women are post-menopa...
Malignant mixed Mullerian tumour (MMMT) of the uterus, also known a uterine carcinosarcoma, is the commonest (up to 50%) uterine sarcoma. They are thought to account for 2-8% of all malignant uterine cancers 1-2. The uterus is the commonest site for malignant mixed Mullerian tumours 1.
Malignant neoplasms involving the uterus account for a significant proportion of all female cancers.
They can be classified as:
endometrial carcinoma : commonest: >90% of all uterine malignancies
endometrioid carcinoma of the uterus: commonest histological type, ~80%
papillary serous carcino...
Malignant ovarian lesions can have typical sonographic features, and thus ultrasound is the imaging of choice for initial evaluation of suspected ovarian neoplasm.
The features of malignant ovarian neoplasm on ultrasonography include:
mass >10 cm with locul...
Marshall-Smith syndrome (MSS) is a rare genetic syndrome primarily comprising of the triad of facial dysmorphism, failure to thrive and accelerated osseous maturation 5. Many cases however have wider clinical spectrum.
overgrowth - fetal macrosomia
failure to thriv...
Massive ovarian oedema (MOO) is a very rare disease characterised by a tumour-like, usually unilateral, enlargement of the ovary.
It characteristically presents in young women ~ 6 to 33 years (mean age ~21 years 4).
Most patients present with intermittent ...
Maternal hydronephrosis in pregnancy often results as a physiological phenomenon due to the presence of the fetus.
It is estimated that up to 90 percent of women have some degree of asymptomatic dilatation of the renal calyces, the renal pelves and the upper two-thirds of the ure...
Ovarian dermoid cyst and mature cystic ovarian teratoma are terms often used interchangeably to refer to the most common ovarian neoplasm. These slow-growing tumours contain elements from multiple germ cell layers and are best assessed with ultrasound.
Although they have very simi...
Mayer-Rokitansky-Küster-Hauser syndrome (MRKH) is a congenital anomaly characterised by vaginal agenesis associated with, in the majority of cases, a spectrum of other genitourinary tract abnormalities. MRKH syndrome belongs to class I Mullerian duct anomalies.
Two different forms are described...
McKusick Kaufman syndrome (MKS) is an autosomal recessive multiple malformation syndrome primarily characterised by
hydrometrocolpos - vaginal atresia
congenital heart disease
Meconium pseudocyst formation is a complication that can occur with meconium peritonitis.
It occurs when the extruded meconium becomes walled off within the peritoneal space.
May be seen as a rim calcified mass within the abdomen.
Megalencephaly (MEG) is a disorder characterised by an abnormally large brain. It is primarily a proliferative disorder of embryonic origin. It may involve all or part of the cerebral hemispheres and can be bilateral or unilateral. It is often associated with polymicrogyria or agyria.
Meigs syndrome is defined as the presence of ascites and pleural effusion in association with a benign, usually solid ovarian tumour. In the vast majority (80-90%) of cases, the primary tumour is an ovarian fibroma. Other primary tumours include:
Mendelson syndrome or peptic pneumonia refers to acute chemical pneumonitis caused by the aspiration of stomach contents in patients under general anesthesia.
The etiologic agents is believed to be aspiration of acidic stomach contents, other compounds, e.g. bile, may also play a rol...
Menouria (Youssef syndrome) is an uncommon condition in which a vesicouterine fistula results in cyclic haematuria. Vesicouterine fistulas are the rarest of all urinary fistulas, accounting for just 4% of all such fistulas 3. It occurs most commonly after cesarean section.
Mesomelia refers to a shortening of the middle (intermediate) portion of a limb.
mesomelia-synostoses syndrome (MSS) or mesomelic dysplasia with acral synostoses1
Ellis van-Creveld syndrome 2
Mesonephric carcinoma of the cervix is an extremely rare histological sub type of cervical cancer. It falls under the sub group of adenocarcinoma of the cervix. This is a slightly confusing entitiy since some authors have used this term as synonymous with clear cell carcinoma of the cervix 6.
Metastases to the ovary are relatively common with a documented incidence of 5-30% of all malignant ovarian masses.
These may be incorrectly grouped under Krukenberg tumors, which are signet cell containing tumours that form only 30-40% of all ovarian metastases.
Metastases to the uterine cervix is an extremely uncommon with near to nothing publications in radiological literature at the time of writing. Generally, invasion of the uterine cervix (i.e. from vaginal and primary uterine malignancies) are excluded in its definition. There have been occasional...
Metastases to the vagina are more common than primary vaginal malignancies and account for >80% of vaginal tumours.
Metastases usually spread from contiguous sites most commonly, with lymphatic and hematogenous metastases also recognised.
Tumors that metastasise to the vagina includ...
Metatrophic dysplasia is a rare group of skeletal dysplasia. It is part of the wider category of rhizomelic dwarfism. Disorders in this group include:
lethal metatropic dysplasia (type 2) or hyperchondrogenesis
lethal hyperplastic metatropic dysplasia (type 1)
Microgenia is a term meaning a small chin. It is somewhat related to but let distinct from the term micrognathia which means a small mandible.
Microgenia can be isolated or be associated with a numer of anomalies which include
camptomelic dysplasia 1
The term micrognathia essentially means a small mandible.
A small mandible occurs secondary to abnormalities of the first branchial arch which in turn are caused by deficient or insufficient migration of neural crest cells and usually occur around the 4th week of gestation.
Microphthalmia essentially means small eyes. It is characterised by a small eye within a small orbit. It can be unilateral or bilateral. It is sometimes defined as a globe with a total axial length (TAL) that is at least two standard deviations below the mean for age.
Midfacial hypoplasia is a type of congenital facial anomaly and can be feature of a number of congenital syndromic anomalies. These include:
chromosome 1p36 deletion syndrome 2
chromosome 18q deletion syndrome
fetal alcohol syndrome
fetal valproate s...
A missing IUCD is considered when the retrieval strings of certain types of intra-uterine contraception devices cannot be seen on physical examination.
The possibilities are
expulsion of IUCD
migration of IUCD
detachment of IUCD thread
uterine perforation in IUCD
Mixed gonadal dysgenesis (MGD) is a type of gonadal dysgenesis characterised by gonadal asymmetry, and/or sex chromosomal mosaicism, as well as retained Müllerian ducts.
Depending on the chromosomal composition, patients may have testes and/or streak gonads.
A monochorionic monoamniotic (MCMA) twin pregnancy is a subtype of monozygotic twin pregnancy. These fetuses share a single chorionic sac, a single amniotic sac and, in general, a single yolk sac.
It accounts for the minority (~5%) of monozygotic twin pregnancies and ~1-2% of al...
A monochorionic twin pregnancy is a type of monozygotic twin pregnancy where the twins share a single chorion. Depending on the sharing of the amnion this can be divided into two types.
monochorionic monoamniotic (MCMA) pregnancy: single amnion
monochorionic diamniotic (MCDA) pregnancy: two am...
A mono nostril falls under the midline facial defects which arise from cleavage anomalies. It can occur as part of many underlying conditions such as
holoprosencephaly: particularly alobar holoprosencephaly
Several other facial anomalies can be associated ...
A monozygotic (MZ) twin pregnancy results from division of single zygote following fertilisation and share similar genetic materials. These twins are therefore always of the same gender.
MZ twins account for approximately 30% of all twin pregnancies 1. The estimated incidence is a...
The mons pubis (plural: montes pubis) refers to the rounded protuberant skin-covered soft tissue overlying the symphysis pubis (in both sexes). It is most prominent in adult females.
In females it forms the most superior part of the vulva and it is also called the mons Veneris (plural: montes V...
MR defecography is a dynamic study for evaluation of the pelvic floor and pelvic organ prolapse.
There are four phases of evaluation:
Method of evaluation
Many variations in the techniques described below exist.
MRI reporting guidelines for cervical cancer help maintain uniformity of reports and assessment of important imaging staging criteria.
The tumour should be measured in three orthogonal planes. Tumours with a maximum diameter >4 cm are usually not amenable to primary radical surgery...
Mucinous carcinoma of the cervix is an uncommon histological sub type of cervical cancer. It falls under the group of adenocarcinoma of the cervix.
As a general rule any mucin-producing tumour will produce very high T2 signal 1.
An enhancing lesion, irregular...
The Müllerian ducts (or paramesonephric ducts) are paired ducts of mesodermal origin in the embryo. They run laterally down the side of the urogenital ridge and terminate at the Müllerian eminence in the primitive urogenital sinus.
In the female, they will develop to form the Fallopian tubes, u...
Müllerian duct anomalies (MDAs) are congenital abnormalities that occur when the Müllerian ducts (paramesonephric ducts) do not develop correctly. This may be as a result of complete agenesis, defective vertical or lateral fusion, or resorption failure.
MDAs are estimated to occur...
The Müllerian duct anomaly classification is a seven point system that can be used to describe a number of embryonic Müllerian duct anomalies:
class I: uterine agenesis / uterine hypoplasia
a: vaginal (uterus: normal / variety of abnormal forms)
Mullerianosis is a rare type of choristoma, in which normal Mullerian-derived structures (endometrium, endosalpinx, and endocervix) are ectopically located in another organ (e.g. the bladder) through a developmental anomaly. Mullerianosis differs from endometriosis in that at least two types of ...
The multiple pterygium syndrome(s) (MPS) refers to a group of disorders which are collectively characterised by multiple soft tissue webs (or pterygia) across the neck and various joints.
They can be broadly classified into two main groups
lethal multiple pterygium syndrome
non lethal multipl...
MURCS association refers to the combination of:
MU: Müllerian duct aplasia
R: renal aplasia /renal agenesis
CS: cervicothoracic somite dysplasia
Mushroom cap sign is one of the important signs of deep rectosigmoid endometriosis seen on T2 weighted MRI sequence. It indicates the submucosal involvement in rectosigmoid region.
Hypertrophic muscularis propria appears as heterogeneous low signal intensity surrou...
Myometrium cysts are cysts seen in the myometrium and these can be differentiated appropriately based on location and sonological or Doppler features.
adenomyosis: the cysts are most often seen in the endomyometrial junction region. They ideally are small <5 mm, however ma...
Myxoid degeneration of a leiomyoma is one of the rarer types of degeneration that can occur in a standard uterine leiomyoma. This term is related but not identical to the term myxoid uterine leiomyoma.
While this type of degeneration is generally considered rare. The higher end o...
Myxoid uterine leiomyoma is a relatively rare pathological subtype of uterine leiomyomas. It is not to be confused with myxoid degeneration of a uterine leiomyoma which is a different entity.
Myxoid leiomyomas contain abundant myxoid material between smooth muscle cells. The lesions ...
Nabothian cysts, also known as a retention cysts of the cervix 11, are non-neoplastic cystic lesions that occur in relation to the uterine cervix.
They are common and some reports suggest that they may be seen in up to 12% of routine pelvic MRI scans 2.
The Naegele's formula is simple arithmetic method for calculating the EDD (estimated date of delivery) based on the LMP (last menstrual period).
To the date of the first day of the LMP (e.g. 22nd June 2008):
add seven days (i.e 29th)
subtract 3 months (i.e March)
add one year (i.e 2009)
A narrow fetal thorax on antenatal ultrasound can be present with a number of anomalies which include:
Jeune syndrome - asphyxiating thoracic dysplasia
short rib polydactyly syndr...
Neu-Laxova syndrome is a lethal autosomal recessive multiple malformation syndrome with a heterogeneous phenotype.
The clinical spectrum can be quite wide and includes:
dermal / cutaneous
severe skin restriction
decreased fetal movement
marked intrauterine gro...
Neural tube defect (NTD) refers to the incomplete closure of the neural tube in very early pregnancy.
The neural tube comprises of a bundle of nerve sheath which closes to form brain at the anterior end and spinal cord at the posterior end. The closure should occur at around the 28th day of co...
Non-gestational choriocarcinoma is choriocarcinoma occurring in the absence of a preceding gestation. As opposed to a gestational choriocarcinoma, this is a much rarer situation.
In women they often tend to occur in ovary. Most ovarian non-gestational choriocarcinomas occur in mixed...
Noonan syndrome (NS) is a genetically and phenotypically heterogenous non aneuploidic congenital RASopathy. Affected individuals can bear some clinical features similar to that of Turner syndrome.
The estimated incidence is at ~1 in 1000-2500 11. As individuals have normal number...
Noonan syndrome with multiple lentigines, previously known as LEOPARD syndrome (LS), is a rare autosomal dominant RASopathy that has many similarities to Noonan syndrome.
Despite a change in formal name, the 'LEOPARD' acronym is still useful to summarise the clinical feat...
Nuchal cord is a term given to the situation where there are one or more loops of umbilical cord wrapped around the fetal neck for ≥360°.
The prevalence is dependent on the extent of coiling and range from ~25% for a single loop to 2.5% for a double loop to ~0.5% for more than two...
The obstetric curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core obstetric knowledge.
Topics pertaining to the normal and abnormal pregnancy, the gravid uterus and fetal environment, placenta, normal fetal development and fet...
This is a basic article for medical students and other non-radiologists
Obstetrics and Gynaecology imaging for students curriculum represents a core set of common pathologies seen on the wards, in theatre and in the emergency O&G patient.
Fundamental to most imaging of the O&G patient is an un...
The OEIS complex refers to the combined occurence of:
bladder exstrophy / cloacal exstrophy
an imperforate anus
and spinal anomalies: e.g
The estimated occurrence is at around 1-200,000 to 400,000 live births 1,8.
An omphalomesenteric duct cyst is a type of true umbilical cord cyst.
The omphalomesenteric duct serves as a communication between the midgut and yolk sac In early embryonic life and usually obliterates between the 9-18th week of gestation. The omphalomesenteric duct cyst is an embry...