The 1-2-3 rule is a simple aide memoire describing the nomenclature of any small simple anechoic structure in the ovary on ultrasound:
<1 cm = follicle
1-2 cm = dominant follicle
>3 cm = cyst
Endometrial stromal tumors (EST) constitute <2% of all uterine tumors and <10% of uterine mesenchymal neoplasms 1.
Over the past four decades, EST classification has gone through various modifications, starting from the earliest study by Norris and Taylor 2. This was primarily due to the rarit...
Three-dimensional (3D) ultrasound is a technique that converts standard 2D grayscale ultrasound images into a volumetric dataset. The 3D image can then be reviewed retrospectively. The technique was developed for problem-solving (particularly in obstetric/gynecologic exams) and to potentially re...
Abdominal and pelvic anatomy encompasses the anatomy of all structures of the abdominal and pelvic cavities.
This anatomy section promotes the use of the Terminologia Anatomica, the global standard for correct gross anatomical nomenclature.
A mnemonic for causes of abdominal distension (6 Fs) is:
F: fulminant mass
Abdominal surface anatomy can be described when viewed from in front of the abdomen in 2 ways:
divided into 9 regions by two vertical and two horizontal imaginary planes
divided into 4 quadrants by single vertical and horizontal imaginary planes
These regions and quadrants are of clinical imp...
Abnormally thickened endometrium on imaging may occur for a number of reasons which may be categorized based on whether or not they are related to pregnancy. Etiologies may also be classified based on whether the patient is premenopausal or postmenopausal.
Abscesses are focal confined collections of suppurative inflammatory material and can be thought of as having three components 1:
a central core consisting of necrotic inflammatory cells and local tissue
peripheral halo of viable neutrophils
surrounded by a 'capsule' with dilated blood vessel...
Acute abdominal pain is a common acute presentation in clinical practice. It encompasses a very broad range of possible etiologies and diagnoses, and imaging is routinely employed as the primary investigative tool in its modern management.
A subgroup of patients with acute abdomina...
Acute pelvic pain is a common presenting symptom to the emergency department and radiologist. Pelvic ultrasound with transabdominal and endovaginal approaches is usually the first line imaging modality.
pain of <3 months duration
Patients also often pres...
Adenocarcinoma of the endometrium is the commonest histological subtype of endometrial cancer and accounts for up to 90% of such cases 1.
Histological sub types
serous type adenocarcinoma of the endometrium
clear cell type adenocarcinoma of the endometrium
Adenocarcinoma of the cervix is a histological subtype of carcinoma of the cervix.
Cervical adenocarcinoma is less common than squamous cell carcinomas (SCC) of the cervix, accounting for ~12.5% of all cervical cancer. Their proportionate prevalence is thought to be increasing an...
Adenoma malignum of the cervix, also referred to as minimal deviation carcinoma / minimal deviation adenocarcinoma, is considered a rare variant of cervical carcinoma. It is thought to represent ~1-3% of all cervical adenocarcinomas.
It can present in a wide age group (~25-70 year...
Adenomatous endometrial hyperplasia is a type of endometrial hyperplasia.
The peak incidence is around 40-50 years of age.
Both endogenous and exogenous estrogen exposure are considered important factors in its etiology 1.
An adenomyoma is a focal region of adenomyosis resulting in a mass, which is difficult to distinguish from a uterine fibroid, although in general the degree to which the contour of the uterus is distorted is less marked in adenomyosis 2. Additionally, the 'mass' is poorly defined and blends with...
Adenomyosis is a common uterine condition of ectopic endometrial tissue in the myometrium, sometimes considered a spectrum of endometriosis. Although most commonly asymptomatic, it may present with menorrhagia and dysmenorrhea. Pelvic imaging (i.e. ultrasound, MRI) may show characteristic findin...
An adenomyotic cyst is an extremely rare variation of cystic adenomyosis. The lesion consists of a large hemorrhagic cyst, which is partly or entirely surrounded by a solid wall. It can be entirely within the myometrium, submucosal, or subserosal and frequently is associated with symptoms of men...
Adenosquamous cell carcinoma (ASC) of the cervix is a rare histological subtype of cervical carcinoma.
It has components of both cervical adenocarcinoma and cervical squamous cell carcinoma.
An adenosquamous histology appears to be an independent predictor of poor outcome...
Adenosquamous carcinoma of the endometrium is a rare histological sub type of endometrial cancer.
In general it occurs in a slightly younger group when compared with pure adenocarcinoma of the endometrium 4.
It contains both malignant glandular and malignant squamous components. Adenosquamous...
The term adnexal torsion refers to torsion of the pelvic adnexal structures. This can encompass ovarian torsion + / - tubal torsion.
Adult granulosa cell tumor of the ovary is a type of ovarian sex cord / stromal tumor. They are by far the most frequent subtype of granulosa cell tumors of the ovary (95%) and are commoner than the juvenile granulosa tumor of the ovary.
Approximately two-thirds of this subtype ar...
Aggressive angiomyxomas are rare tumors that arise in the pelvis and typically cross the levator ani muscles. Despite its name, it is essentially a benign tumor and the term "aggressive" is given due to a predilection for local recurrence. Only rarely does it metastasize.
It is se...
The anatomy curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core anatomy knowledge for radiologists and imaging specialists.
Head and neck anatomy
Abdominal and pelvic anatomy
Androgen insensitivity syndrome (AIS), also known as the testicular feminisation syndrome, results from end-organ resistance to androgens, particularly testosterone. AIS may be complete or incomplete with variable imaging findings.
The incidence may vary depending on whether it i...
Anorexia nervosa is a psychiatric disorder characterized by distorted self-perception of body weight leading to starvation, obsession with remaining underweight, and an excessive fear of gaining weight. One in five patients with anorexia dies, due to complications of the disease.
Antral follicle count (AFC) or basal antral follicle count is a test performed to check a female individual's ovarian reserve.
A female is born with a lifetime supply of eggs and as she enters puberty these eggs develop. During and after puberty these follicles develop and are relea...
An arcuate uterus is a mildly variant shape of the uterus. It is technically one of the Müllerian duct anomalies, but is often classified as a normal variant. It is the uterine anomaly that is least commonly associated with reproductive failure. Arcuate uterus can be characterized with ultrasoun...
Asherman syndrome, also known as uterine synechiae, is a condition characterized by the formation of intrauterine adhesions, which are usually sequela from injury to the endometrium, and is often associated with infertility.
There is a tendency for the condition to develop soon af...
Bartholin gland abscess is a complication that may result from an infected Bartholin gland cyst.
Abscesses are usually in a similar location to Bartholin gland cysts. Features of Bartholin gland abscess are otherwise similar to Bartholin gland cyst described in separate ...
Bartholin gland cysts are located in the posterolateral inferior third of the vagina and are associated with the labia majora.
Most patients are asymptomatic 4.
infection: may turn into Bartholin gland abscesses
rare instances of development of adenocarc...
The Bartholin glands, also known as greater vestibular glands, are paired pea-sized structures, lying on either side of the vaginal opening, and are homologous to the bulbourethral (Cowper) glands in the male. They form part of the vulva.
These glands are described as less than 1...
Bartholin gland tumors represent neoplasms of the Bartholin glands.
squamous cell carcinoma of the Bartholin gland: tends to be the most common histological subtype
adenocarcinoma of the Bartholin gland
adenoid cystic carcinoma of the Bartholin gland
The beads-on-a-string sign is used to refer to the classic morphologic changes in the Fallopian tubes as a result of chronic salpingitis.
The "string" alludes to the notably thin salpingeal wall, while the hyperechoic mural nodules constitute the "beads" 1.
Benign metastasizing leiomyomas are a rare metastatic phenomenon that is observed when a pelvic leiomyoma is present.
Women who have undergone hysterectomy for leiomyomas are most commonly affected.
Patients are usually asymptomatic at presentation. A histo...
There are a number of benign metastasizing tumors:
benign metastasizing meningioma 1,2
benign metastasizing leiomyoma 3
primary adenoma of thyroid 4
giant cell tumor of bone 5
A bicornuate uterus is a type of uterine duplication anomaly. It can be classified as a class IV Mullerian duct anomaly.
Overall, congenital uterine anomalies occur in ~1.5% of females (range 0.1-3%). Bicornuate uteri are thought to represent ~25% (range 10-39%) of Mullerian duct ...
Body packing refers to the internal concealment of drugs within the gastrointestinal tract or other orifices. People who do this may be called body packers, (drug) mules, stuffers, couriers or swallowers. Drugs may be concealed within condoms, foil, latex or cellophane.
There is ...
Borderline ovarian serous cystadenomas lie in the intermediate range in the spectrum of ovarian serous tumors and represent approximately 15% of all serous tumors.
They present at a younger age group 1-2 than the more malignant serous cystadenocarcinomas with a peak age of present...
Brenner tumors are an uncommon surface epithelial tumor of the ovary. It was originally known as a transitional cell tumor due to its histological similarity to the urothelium. Brenner tumors account for ~3% of ovarian epithelial neoplasms. They can very rarely occur in other locations, includin...
The bridging vessel sign refers to an appearance of vessels coursing from the uterus into an adjoining pelvic mass (a vascular bridge). This sign helps to differentiate a pedunculated subserosal uterine leiomyoma from other juxtauterine masses of ovarian, adnexal or bowel origin.
Color and powe...
The broad ligament is the lateral folds of the parietal peritoneum which reflect over the upper genital tract.
The broad ligament extends from the lateral aspect of the uterus to the lateral pelvic wall and can be divided into three main components - the mesosalpinx, mesovarium a...
A mnemonic for the contents of the broad ligament is:
B: bundle (ovarian neurovascular bundle)
R: round ligament
O: ovarian ligament
A: artifacts (vestigial structures)
D: duct (oviduct)
Broad ligament leiomyomas are extra-uterine leiomyomas that occur in relation to the broad ligament.
Broad ligament leiomyomas are also referred as a type of parasitic leiomyomas 5.
While in most cases broad ligament leiomyomas are asymptomatic, patients ma...
CA-125 is a high-molecular-weight glycoprotein found on the surface of Mullerian and coelomic epithelial-derived cell types, and is the best known tumor marker for epithelial ovarian cancer 6. Importantly, it may also be elevated in several other conditions (see differential diagnosis section be...
CA 27-29 is a tumor marker and is a soluble form of glycoprotein MUC1. It may be elevated in patients with breast cancer. Tumors of the colon, stomach, kidney, lung, ovary, pancreas, uterus, and liver may also raise CA 27-29 levels.
Certain non-malignant conditions are also associated with its ...
The canal of Nuck is an abnormal patent pouch of parietal peritoneum extending anteriorly from the round ligament of the uterus into the labia majora through the inguinal ring into the inguinal canal. Incomplete obliteration of this canal is known as a patent processus vaginalis and can result i...
Carcinoma of the cervix is a malignancy arising from the cervix. It is the third most common gynecologic malignancy (after endometrial and ovarian).
It typically presents in younger women with the average age of onset at around 45 years.
human papillomavirus (HPV) ...
Carcinosarcomas are highly malignant biphasic tumors with both carcinomatous (epithelial) and sarcomatous (bone, cartilage, or skeletal muscle) components.
It can arise in many organs:
lung 5: pulmonary carcinosarcoma
esophagus 1: esophageal carcinosarcoma
genitourinary tract 2
Red or carneous degeneration is one of four main types of degeneration that can involve a uterine leiomyoma. While it is an uncommon type of degeneration, it is thought to be the most common form of degeneration of a leiomyoma during pregnancy 3.
Patients with a leiomyoma...
Catamenial pneumothorax is a rare type of pneumothorax and is characterized by the recurrent accumulation of air in the thoracic space related to menstruation.
It may represent up to one-third of women with spontaneous pneumothoraces 1. Patient history may or may not be positive f...
Staging of cervical cancer can either be based on the TNM or FIGO system.
Revised FIGO staging of cervical carcinoma 2018 8
FIGO no longer includes Stage 0 (Tis)
I: confined to cervix uteri (extension to the corpus should be disregarded)
IA: invasive carcinoma only diagnosed by microscopy
Cervical incompetence refers to a painless spontaneous dilatation of the cervix and is a common cause of second trimester pregnancy failure.
The estimated incidence varies geographically and generally thought to be around 1-1.5% of all pregnancies 1,15.
In obstetric and gynecological imaging, the cervical length is defined as the distance between the internal cervical os and the external cervical os.
the cervical length is most accurately assessed on a transvaginal scan with an empty bladder
in a normal gr...
Cervical plicae palmatae are normal folds seen on the anterior and posterior walls of the cervical canal. They are often described as longitudinal ridges or oblique elevation.
Sometimes they are identified on MRI, and one must make sure not to misinterpret this finding as abnormal. Studies repo...
Cervical polyps are polypoid growths projecting into the cervical canal. They can be one of the most common causes of intermenstrual vaginal bleeding.
Most patients are perimenopausal at the time of presentation, especially in the 5th decade of life. They are the most common mass...
The term cervical stenosis can refer to:
stenosis of the uterine cervix
bony cervical canal stenosis (cervical spinal stenosis)
The cervix or uterine cervix is the lower constricted segment of the uterus providing the passage between the uterus proper and the vagina.
The cervix is somewhat conical in shape, with its truncated apex directed posteriorly and inferiorly. The inferior aspect of the cervix pro...
Cesarean section scar diverticulum is a form of outpouching located in the anterior lower uterine cavity at the site of cesarean section scar.
There is some similarity with the term Cesarean scar niche.
Choriocarcinoma is an aggressive, highly vascular tumor. When it is associated with gestation, it is often considered part of the spectrum of gestational trophoblastic disease; it is then termed gestational choriocarcinoma. When it occurs in the absence of preceding gestation, it is termed non-g...
The staging system for choriocarcinoma (usually refers to uterine choriocarcinoma) is the FIGO staging system and is as follows 1:
stage I: disease limited to the uterus
stage II: disease out of the uterus but limited to the female genital tract
stage III: metastasis in the lung with or with...
There are many signs in radiology that are related to Christmas:
snowcap sign in avascular necrosis
in total anomalous pulmonary venous return
in pituitary macroadenomas
snowstorm appearance in complete hydatidiform and testicular microlithiasis
holly leaf sign in calcified pl...
Chronic pelvic pain is a common presenting symptom to primary care physicians and to radiologists. Pelvic ultrasound with transabdominal and endovaginal approaches are usually the first line imaging modality. MRI may be performed afterwards.
pain of >6 mo...
Clear cell carcinoma of the cervix (CCCC) is a rare adenocarcinoma subtype of cervical cancer.
Due to association with diethylstilbestrol (DES) exposure in some patients, this subtype may have a younger age at presentation than other histological subtypes. This subtype can sometim...
Clear cell carcinoma (CCC) of the endometrium is an uncommon histological subtype of endometrial cancer. It only accounts for 1-5.5% of all endometrial carcinomas, and it is often associated with an aggressive clinical behavior and a poorer outcome 4-5. Only occasional case reports have describe...
Clear cell carcinoma of the ovary is a type of malignant ovarian epithelial tumor.
They represent ~2-5% of all ovarian carcinomas and ~3.7%-12% of epithelial ovarian neoplasms. The mean age at presentation is ~10 years younger than for other ovarian epithelial tumors (peaks ~55 ag...
Coexistent molar pregnancy refers to an extremely rare situation where there is a molar pregnancy occurring simultaneously with normal intra-uterine pregnancy.
The estimated incidence is at ~1:10,000-100,000 gestations (for a complete hydatidiform mole and a normal pregnancy) 2.
The cogwheel sign refers to an imaging appearance in pelvic imaging of thickening loops of the Fallopian tube seen on cross-section. There are infolding projections (sometimes looking like nodules) into the Fallopian tube lumen which is likened to that of a cogwheel. The sign is typically descri...
A collision tumor of the ovary is an uncommon ovarian neoplasm where there is co-existence of two adjacent but histologically distinct tumors with no histologic admixture at the interface.
The exact pathogenesis is not well known. They are most commonly composed of ovarian teratoma (...
Colovaginal fistula is one form of genitourinary fistula. It is also sometimes classed under a type of gastro-intestinal fistula.
It refers to a communication between the colon (typically the rectum or sigmoid colon) with the vagina.
At times, specific terms are used dependent on th...
A simple mnemonic to recall a list of commonly calcifying metastases is:
B: breast cancer
T: papillary thyroid cancer
O: ovarian cancer (especially mucinous)
M: mucinous adenocarcinoma (especially colorectal carcinoma)
There are many classification systems for congenital utero-vaginal anomalies. These include:
Buttram and Gibbons classification 2
American Fertility Society (AFS) classification
Modified Rock and Adam - AFS classification
Modified Rock and Adam - AFS classification
This classification divid...
The corpus albicans is a fibrous scar that results from the involution of the corpus luteum if fertilisation does not occur. When seen on ultrasound, it is a small, lobulated echogenic intra-ovarian lesion.
History and etymology
It is Latin for "whitening body", after the white appearance of ...
Corpus luteal (CL) cysts are a type of functional ovarian cyst that results when a corpus luteum fails to regress following the release of an ovum. When associated with pregnancy, it is the most common pelvic mass encountered within the 1st trimester. There is also some overlap with the term "he...
Ruptured corpus luteal cysts are one of the commonest causes of spontaneous hemoperitoneum in a woman of reproductive age.
Presentation is variable, ranging from completely asymptomatic to severe abdominal pain due to peritoneal irritation.
The corpus luteum i...
The corpus luteum (plural: corpora lutea) is a temporary endocrine structure involved in ovulation and early pregnancy.
During ovulation, the primary follicle forms the secondary follicle and subsequently the mature vesicular follicle.
At ovulation the follicle ruptures expelling the ovum into...
Cumulus oophorus refers to an appearance in the ovary in which multiple granulosa cells enlarge around a developing oocyte. These support cells ("cumulus cells") serve multiple functions in the maturation of the oocyte. They may occasionally be seen during a pelvic ultrasound, and should not be ...
Cystic adenomyosis is a rare variant of adenomyosis and is believed to the result of repeated focal hemorrhages resulting in cystic spaces filled with altered blood products.
MRI is the most sensitive and specific imaging modality for this diagnosis and will demonstr...
Cystic degeneration is an uncommon type of degeneration that a uterine leiomyoma can undergo.
This type of degeneration is thought to represent ~4% of all types of degeneration.
When the leiomyomas increase in size, the vascular supply to it becomes inadequate and lea...
Cystic endometrial atrophy is a benign process that can occur as part of tamoxifen-associated endometrial change.
It is diagnosed histologically when multiple cystic spaces (dilated glands) lined with atrophic epithelium are present within a dense fibrous stroma.
At hysteroscopy, ...
Cystic endometrial hyperplasia is the most common as well as the most benign form of endometrial hyperplasia.
Typically shows endometrial thickening with associated cysts.
For imaging appearences consider:
prolonged proliferative phas...
A cystic retroperitoneal lesion can carry a relatively broad differenital which includes:
retroperitoneal cystic lymphangioma
retroperitoneal mucinous cystadenoma
retroperitoneal cystic teratoma
retroperitoenal cystic mesothelioma
pseudomyxoma retroperitonei with cystic change
The deepest (maximal) vertical pocket (DVP) depth is considered a reliable method for assessing amniotic fluid volume on ultrasound 1,2. It is performed by assessing a pocket of a maximal depth of amniotic fluid which is free of an umbilical cord and fetal parts.
The usually accepted values are...
The deep inguinal nodes are located within the femoral sheath, medial to the femoral vein. They receive afferent lymphatic drainage from the deep lymphatics of the distal lower extremity and perineum (e.g. glans penis / clitoris), and drain proximally into external iliac lymph nodes via channels...
The deep perineal pouch is an anatomic space superior (deep) to the perineal membrane in the urogenital triangle of the perineum, anterior to the transverse line between the ischial tuberosities.
The deep perineal pouch is above (deep to) the perineal membrane in the urogenital t...
The cul-de-sac, also known as the pouch of Douglas or rectouterine pouch, is an extension of the postero-inferior reflection of the peritoneal fold between the uterus (anteriorly) and rectum (posteriorly). It is the most inferior aspect of the peritoneal cavity and therefore the first location w...
Diffuse or disseminated peritoneal leiomyomatosis, also known as leiomyomatosis peritonealis disseminata, is an exceedingly rare benign disorder characterized by multiple vascular leiomyomas growing along the submesothelial tissues of the abdominopelvic peritoneum.
It is usually d...
Diffuse uterine adenomyosis is the most common of uterine adenomyosis. For the discussion of adenomyosis, please refer to the parent article - adenomyosis of the uterus.
Diffuse adenomyosis may account for ~2/3rd of uterine adenomyosis.
Diffuse adenomyosis can be even ...
Diffuse uterine leiomyomatosis is a benign and extremely rare condition in which the uterus is symmetrically enlarged as a result of the almost complete replacement of the myometrium by innumerable poorly defined, confluent leiomyomatous nodules.
Initial symptoms of the ...
Disorder of gender development refers to the spectrum of rare congenital conditions in where there is an atypical development of chromosomal, gonadal, or anatomic sex.
They can be classified broadly into four categories on the basis of gonadal histologic features which include:
A dominant ovarian follicle refers to the follicle that enlarges to release an ovum during a menstural cycle. Usually approximately 10 Graafian follicles begin to mature where one becomes a dominant follicle and the rest become atretic ovarian follicles. After release of the ovum the remainder o...
The dot-dash pattern (dermoid mesh) is one of the characteristic sonographic appearances of an ovarian dermoid cyst. It refers to the short and long echogenic lines which are often seen within a dermoid cyst and are due to the presence of hair.
A dysgerminoma refers to a class of tumor with germ cell origin.
This can refer to:
germ cell tumors
Ectopic pregnancy refers to the implantation of a fertilised ovum outside of the uterine cavity.
The overall incidence has increased over the last few decades and is currently thought to affect 1-2% of pregnancies. The risk is as high as 18% for first trimester pregnancies with bl...