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-class 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 the rectosigmoid colon.
The hypertrophic muscularis propria appears as heterogeneous low signal intensity surrounded by the high signal...
Myometrial cysts are cysts seen in the myometrium and these can be differentiated appropriately based on location and sonological or Doppler features.
They can arise from variable aetiology and include:
adenomyosis: these cysts are most often seen in the endomyometrial ju...
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 leiomyomas are a relatively rare pathological subtype of uterine leiomyomas.
They are 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 ...
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.
Nabothian is generally written without capitalisation, i.e. 'nabothian', and not 'Nabothian', as it is an adjectival form derived from ...
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)
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
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 caudally and spinal cord rostrally. The closure should occur at around the 28th day of conception failing which...
Non-gestational choriocarcinoma is choriocarcinoma occurring in the absence of a preceding gestation. As opposed to gestational choriocarcinoma, this is a much rarer situation.
In women, they often tend to occur in the ovary. Most ovarian non-gestational choriocarcinomas occur in mix...
Noonan syndrome (NS) is a genetically and phenotypically heterogeneous 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 10. As individuals have normal numbe...
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 dependant 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...
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...
Oral-facial-digital syndromes (OFDS) are a group of rare genetic developmental disorder that affects the mouth, face, digits and also may cause some problems on the central nervous, kidney and the other organs.
Some publications have classified at least 13 forms of OFDS based on...
An ovarian adenofibroma is a type of ovarian epithelial tumour. Many authors however overlap this entity with an ovarian cystadenofibroma and consider these tumours often as part of an adenofibroma - cystadenofibroma spectrum.
Adenofibromas are benign compound tumours composed of int...
The ovarian-adnexal reporting and data system (O-RADS) is an ultrasound risk stratification and management system for the evaluation of ovarian and other adnexal masses.
These recommendations function have been published to guide the management of "average-risk patients without acute symptoms" ...
The ovarian artery is a paired structure and is the main gonadal artery in females.
The ovarian artery arises anterolaterally from the aorta just inferior to the renal arteries and superior to the inferior mesenteric artery (between L2 and L3).
Descends caudally ...
Ovarian borderline mucinous cystadenomas are a subtype of ovarian mucinous tumours and, as the name stands, are intermediate between mucinous cystadenomas and mucinous cystadenocarcinomas.
They account for ~ 10-15% of all ovarian mucinous tumours.
They are microscopica...
The most commonly adopted ovarian cancer staging system is the FIGO staging system. The most recent staging system is from 2014 1:
CT is considered the best imaging modality for staging ovarian cancer. 4.
stage I: tumour limited to the ovaries
tumour limited to one ovary
Ovarian carcinoid tumours are very rare sub type of ovarian tumour. They are usually classified under ovarian germ cell tumours (monodermal teratoma 5). The term carcinoid tumour of the ovary can be used to described primary ovarian carcinoid tumours or metastatic carcinoid tumours to the ovary....
An ovarian choriocarcinoma is a rare sub type of ovarian germ cell tumour.
They account for less than 1% of ovarian tumours.
In pre-menarchal patients, the tumours manifest with iso-sexual precocity (approximately 50% of cases) and other symptoms associate...
Ovarian cysts are commonly encountered in gynaecological imaging, and vary widely in aetiology, from physiologic, to complex benign, to neoplastic.
Small cystic ovarian structures should be considered normal ovarian follicles unless the patient is pre-pubertal, post-menopausal, pregn...
An ovarian cystadenocarcinofibroma (CACF) is an extremely rare ovarian tumour. The tumour has a fibrous component is considered as the malignant counterpart of an ovarian cystadenofibroma (CAF) 1. There is very little literature on the imaging findings of these.
Ovarian cystadenofibromas are a relatively uncommon benign epithelial ovarian tumour where the fibrous stroma remains a dominant component of the neoplasm. As a group, they are thought to represent ~1.7 % of all benign ovarian tumours 3.
Lesions can be bilateral in ~15% of cases. Alt...
Ovarian cystadenoma is a broad term given to a certain types of ovarian epithelial tumours. This can include
ovarian serous cystadenoma
ovarian borderline serous cystadenoma
ovarian mucinous cystadenoma
ovarian borderline mucinous cystadenoma
Ovarian cystic neoplasms can be either benign or malignant and can arise from epithelial, stromal, or germ cell components. In general, the risk of malignancy in unilocular cystic tumours <10 cm in women over the age of 50 years is thought to be low 3-4.
ovarian mature cystic teratoma
Ovarian dysgerminomas are a type of germ cell tumour of the ovary. They are the most common malignant germ cell tumours of the ovary and are thought to account for ~1% of all ovarian neoplasms 5.
They are rare ovarian tumours that occur predominantly in young women (majority occur...
Ovarian ectopic pregnancies are rare (1-3%) when compared to other types of ectopic pregnancy such as tubal ectopic.
Risk factors include pelvic inflammatory disease, IUCD use, endometriosis, in vitro fertilisation-embryo transfer 3, and previous adnexal surgery 4. Pa...
Ovarian embryonal carcinomas are rare and malignant germ cell tumours of the ovary.
It is found predominantly in children and adolescents (average age 14 years).
Precocious puberty or menstrual irregularity occurs in 60% 2. The tumour can secrete beta-hCG a...
Ovarian fibromas are a benign ovarian tumour of sex cord / stromal origin. Although fibromas account for ~4% of all ovarian neoplasms, they are the most common sex cord ovarian tumour.
Fibromas occur at all ages but are most frequently seen in middle-aged women.
Ovarian fibromatosis (OF) refers to a rare benign phenomenon where there is tumour-like ovarian enlargement due to diffuse ovarian fibrosis.
It may have a predilection towards younger pre-menopausal females (age range around 13-39 years) with a mean age of presentation of 25 years...
Ovarian fibrosarcoma is a malignant mesenchymal fibroblastic tumour of the ovary that has multiple mitotic figures which is the most important factor in histopathological diagnosis (4 or more mitotic figure per 10 high power fields).
Ovarian fibrosarcoma is a very rare malignant ...
Ovarian fibrothecomas comprise tumours in the spectrum of ovarian sex cord / stromal tumours where there are components of both an ovarian fibroma and an ovarian thecoma.
Most occur in adult women, with ~66% in postmenopausal women. Although they account for ~1% of all ovarian tu...
An ovarian follicle (also known as a Graafian follicle in its mature state) is the basic unit of female reproductive biology and is composed of roughly spherical aggregations of cells. It contains a single oocyte.
An ovarian follicle can be initiated to grow and develop, culminating in ovulati...
An ovarian follicular cyst is type of simple physiological ovarian cyst.
The terms "ovarian cyst" and "ovarian follilcular cyst" are often used interchangeably. These two terms describe lesions >3 cm, and it is important to differentiate them from an "ovarian follicle" which is <3 ...
Ovarian hyperstimulation syndrome (OHSS) is a complication of ovarian stimulation treatment (ovarian induction therapy) for in vitro fertilisation. Rarely, it may also occur as a spontaneous event in pregnancy (see spontaneous ovarian hyperstimulation later in the article).
The clinical syndrom...
Ovarian hyperthecosis (OHT) is a condition where there is a presence of luteinized thecal cells within a hyperplastic ovarian stroma.
Clinical manifestations include hyperandrogenism, obesity, hypertension, and impaired glucose tolerance. Virilization has been reported to...
A hypointense ovarian lesion on T2 weighted MRI is usually a sign of benignity. The low signal is considered to be due to fibrosis and blood products 1.
Lesions that can give this appearance include 1:
Ovarian lymphoma can refer to
primary involvement of the ovaries with lymphoma (i.e. primary ovarian lymphoma): very rare
secondary ovarian involvement of the ovaries with generalised lymphoma (i.e. secondary ovarian lymphoma): more common scenario
Mucinous cystadenocarcinoma of the ovary is a rare malignant ovarian mucinous tumour. This type can account for 5-10% of all ovarian mucinous tumours. It is a type of ovarian epithelial tumour.
Retrospective studies have suggested that many mucinous carcinomas initially diagnosed as...
Mucinous cystadenoma of the ovary is at the benign end of the spectrum of mucin-containing epithelial ovarian tumours.
The estimated peak incidence is at around 30-50 years of age.
They comprise approximately 80% of mucinous ovarian tumours and 20-25% of all benign ovarian tumou...
Ovarian mucinous tumours are a subgroup of ovarian epithelial tumours. They represent 10-15% of all ovarian tumours and ~10% of all malignant ovarian tumours. They are subdivided according to their malignant potential and clinical behaviour into:
ovarian mucinous cystadenoma
Ovarian serous cystadenocarcinoma is the malignant form of ovarian serous tumour, the most common type of ovarian epithelial tumour. It is the most common type of ovarian malignancy.
Increasingly, high-grade serous carcinoma and low-grade serous carcinoma are recognised as distinct tumour types...
Ovarian serous cystadenomas are a type of benign ovarian epithelial tumour at the benign end of the spectrum of ovarian serous tumours.
Serous ovarian tumours are traditionally described with a "cyst-" prefix because of their primarily cystic composition, e.g. cystadenoma, cystaden...
Ovarian serous neoplasms are the commonest of four general types of the epithelial ovarian tumours, and are more prevalent than the mucinous ovarian tumours.
Serous ovarian neoplasms are subdivided into benign, borderline, and malignant lesions according to their malignant potential and clinica...
Ovarian Sertoli-Leydig cell tumours (SLCT), also known as an ovarian androblastomas, are a subtype of ovarian sex cord-stromal tumour.
They are rare and only account for ~0.5% of all ovarian tumours. While they can present at any age, they typically present <30 years old, with a m...
Ovarian teratomas is the most common group of ovarian germ cell tumours.
They can be divided into 3 main sub types
mature ovarian teratoma
immature ovarian teratoma
struma ovarii tumour
Ovarian thecomas are benign ovarian tumours of sex cord / stromal (mesenchymal) origin. They are thought to account for approximately 0.5-1% of all ovarian tumours. As ovarian thecomas secrete oestrogen, they are described as functional ovarian tumours.
They typically present in o...
Ovarian torsion, also sometimes termed adnexal torsion or tubo-ovarian torsion, refers to rotation of the ovary and portion of the fallopian tube on the supplying vascular pedicle.
It can be intermittent or sustained and results in venous, arterial and lymphatic stasis. It is a gynaecological ...
Ovarian transposition is a surgical procedure in which the ovaries are displaced from the pelvis before pelvic radiation therapy in order to protect them from radiation injury.
It is performed in premenopausal women with a variety of pelvic malignancies (e.g cervical cancer, rectal cancer, and ...
Ovarian tumours are relatively common and account for ~6% of female malignancies. This article focuses on the general classification of ovarian tumours. For specific features, refer to the subarticles.
Primary ovarian tumours
Surface epithelial-stromal ovarian tumours (60-...
There are several ovarian tumours associated with endometrial thickening and is often due to oestrogenic effects of the ovarian tumour.
Such tumours include:
ovarian epithelial tumours
endometroid carcinoma of the ovary
may have synchronous endometrial carcinoma or endometrial hyperplasia, p...
Ovarian vein syndrome is a relatively rare condition where a dilated ovarian vein (ovarian venous varix) causes notching, dilatation, or obstruction of the ureter. This is usually secondary to varicoses of the ovarian vein or ovarian vein thrombosis and occurs at the point where the ovarian vein...
Ovarian vein thrombosis (actually most often thrombophlebitis) occurs most commonly in postpartum patients and can result in pulmonary emboli. A presentation is usually with acute pelvic pain in the postpartum period, then termed puerperal ovarian vein thrombosis or postpartum ovarian vein throm...
Ovarian yolk sac tumours, also known as endodermal sinus tumours, are a type of ovarian germ cell tumours.
Ovarian yolk sac tumour is a rare malignant ovarian germ cell tumour that usually occurs around the second decade of life. It is considered the most common malignant germ cel...
The ovaries are paired female gonads of the reproductive and endocrine systems. They lie within the ovarian fossa on the posterior wall of the true pelvis.
The ovaries are firm and ovoid in shape and measure approximately 1.5-3.0 cm × 1.5-3.0 cm × 1.0-2.0 cm (length x width x th...
Overlapping fetal fingers is an antenatal ultrasound observation where the fetal fingers are seen to overlap each other. It may be seen seen with a concurrent clenched fetal hand. If the hand is clenched typically the 2nd finger is seen to overlap the 3rd 4.
a well re...
p16 is a widely used immunohistochemical marker indicating expression of the cell cycle protein cyclin-dependant kinase inhibitor 2A, which is upregulated by human papillomavirus (HPV) infection. In the uterine cervix, p16 positivity supports the diagnosis of a high-grade squamous intraepithelia...
A papillary serous carcinoma of the cervix (PSCC) is an uncommon histological type of cervical cancer. It is considered a sub type of adenocarcinoma of the cervix.
Accodring to some studies, there was a bimodal age distribution, with one peak occurring before the age of 40 years ...
Papillary serous carcinoma of the endometrium is an uncommon histological subtype of endometrial carcinoma accounting for only 5-10% of all such tumours 2. It is considered type II endometrial adenocarcinoma and has a clinically aggressive form with an early extension of the tumour via Fallopian...
Papillary squamous cell carcinoma (PSCC) of the cervix is a distinct subtype of squamous cell carcinoma of the cervix.
These tumours are characterised by a papillary architecture containing fibrovascular cores and moderate to severe dysplasia without any of frank keratinisation and k...
The parametrium is a band of fibrous tissue that separates the supravaginal portion of the cervix from the bladder. It extends on to its sides and laterally between the layers of the broad ligaments.
The uterine artery and ovarian ligament are located in the parametrium.
The parametrium is imp...
Paraovarian cysts (POCs) are remnants of Wolffian duct in the mesosalpinx that do not arise from the ovary. They account for ~10-20% of adnexal masses 3,4.
Paraovarian cysts are also sometimes referred to as paratubal cysts or hydatid cysts of Morgagni 14.
Paraovarian cystadenoma is a usually benign adnexal tumour that does not arise from the ovary. There is an association with Von Hippel Lindau syndrome.
typically seen as a unilateral cystic adnexal lesion
may be a simple cyst, or contain solid nodular ...
Parasitic leiomyomas are considered a type of extra-uterine leiomyoma and present as peritoneal pelvic benign smooth-muscle masses separate from the uterus.
It likely originates as a pedunculated subserosal leiomyoma that twists and torses from its uterine pedicle. The contact with ...
The paraurethral ducts (or Skene ducts) drain the paraurethral glands of the female urethra. There is one duct, draining each gland, on each side, just proximal to the external urethral meatus.
History and etymology
Skene ducts are named after the Scottish-American gynaecologist Alexander Joh...
Paraurethral duct cysts are retention cysts that form secondary to inflammatory obstruction of the paraurethral (Skene) ducts in females.
The cysts are lined by stratified squamous epithelium due to their origin from the urogenital sinus.
Partial hydatidiform mole is a type of hydatidiform mole, which in turn falls under the spectrum of gestational trophoblastic disease.
Clinical signs and symptoms such as abdominal pain, cramps of the lower abdomen and vaginal bleeding during pregnancy are common but non...
Parturition-induced pelvic instability is a rare condition seen in women following vaginal delivery.
The incidence of symphyseal rupture after vaginal delivery ranges from one in 600 to one in 30,000 deliveries 1.
Predisposing factors include multiparity, complicated delivery, ...
A pelvic abscess refers to a walled-off collection of pus in the pelvis.
Some of the causes include:
pelvic inflammatory disease (tubo-ovarian abscess)
iatrogenic e.g. post surgical
inflammatory bowel disease
pelvic actinomycosis infection
Pelvic actinomycosis infection is rare but serious infection caused by Actinomyces sp., an opportunistic gram-positive bacteria usually introduced by foreign bodies specially IUCDs, surgery, or trauma. It generally falls under the broader spectrum of pelvic inflammatory disease.
A dedicated pelvic MRI protocol is very useful for imaging assessment of cervical carcinoma.
Although the FIGO is a clinical staging, the 2009 revised FIGO staging encourages the use of MRI to complement clinical staging.
Imaging is optimally performed after three hours of fasting...
Pelvic congestion syndrome (some prefer pelvic venous insufficiency 9) is a condition that results from retrograde flow through incompetent valves in ovarian veins. It is a commonly missed and potentially-treatable cause of chronic abdominopelvic pain.
It tends to be more common ...
Pelvic inflammatory disease (PID) is a broad term that encompasses a spectrum of infection and inflammation of the upper female genital tract, resulting in a range of abnormalities.
The highest incidence is seen among sexually-active women in their teens, with 75% cases being und...
Pelvic lipomatosis or pelvic fibrolipomatosis represents excessive deposition of fat in pelvis due to overgrowth of adipose cells leading to compression of pelvic organs.
The condition usually presents in patients 20-50 years of age. The condition is predominantly (~66% of cases) ...
Pelvic masses in females carry a broad differential diagnosis:
benign adnexal cyst: 34%
pelvic malignancy: 14%
pelvic inflammatory disease: 8%
Extra-gynaecological masses, e.g. colorectal carcino...
A dedicated MRI protocol is crucial for accurate MRI evaluation of endometrial carcinomas.
Imaging is optimally performed after 3 hours of fasting to reduce bowel peristalsis and following administration of an antiperistaltic agent unless contraindicated.
Supine position using a pelvic phased ...
It is important to have a systematic way of approaching a case with pelvic pain in the exam.
Most examinations are performed using ultrasound. Always say that you would further assess the uterus with 3D ultrasound. You may also say that in my department we would perform a sonohysterogram. Only...
Evaluation of known endometriosis with MRI requires a slightly different protocol to a routine pelvic MRI (see Pelvic MRI protocol: routine), and should probably be reserved for known cases of endometriosis rather than for the assessment of pelvic pain.
IV (or IM) Buscopan® is administered to r...
Pelvic ultrasound is usually the initial modality for imaging gynaecologic pathology, including acute pelvic pain and chronic pelvic pain. The exam normally involves two components: a transabdominal (TA) evaluation and a transvaginal (TV) / endovaginal (EV) evaluation.
Normal ultrasound anatomy...
The term pelvis (plural: pelvises or pelves) can refer to either the bony pelvis or the pelvic cavity.
The bony pelvis is formed by the sacrum and coccyx and a pair of hip bones ("ossa coxae"), which are part of the appendicular skeleton. Its primary function is the transmission of...
Perigestational haemorrhage refers to haemorrhage that occurs around the fetus during the gestational period. The spectrum of haemorrhage includes:
chorionic haemorrhage: caused by the separation of the chorion from the endometrium
subchorionic haemorrhage: most common type, occurs between th...
Getting a film with perigestational haemorrhage in the exam is one of the many exam set-pieces that can be prepared for.
Transabdominal and transvaginal (TV) pelvic ultrasound shows an anteverted uterus with an intrauterine gestational sac. MSD is 20 mm in TV study with a single, ...
Perinatal lethal hypophosphatasia (PLH) is the most severe form of hypophosphatasia. If untreated, it is lethal in all cases.
The estimated incidence is at ~1:100,000 live births.
As with all hypophosphatasia cases, this is due to a mutation in chromosome 1q3...
The perineum is a diamond-shaped region below the pelvic diaphragm and is divided by an imaginary line drawn between the ischial tuberosities into anteriorly the urogenital triangle and posteriorly the anal triangle.
The perineum is bounded by the pubis anteriorly, the ischial tu...
Peritoneal inclusion cysts, also known as peritoneal pseudocysts, are a type of cyst-like structure that appears in relation to the peritoneal surfaces and results from a non-neoplastic reactive mesothelial proliferation.
The nomenclature for this condition can be confusing due to ...