Placental thickness tends to gradually increase with gestational age in a linear fashion. Sonographically, this can be seen to be approximately 1 mm per week and the thickness of the placenta can be used to approximate gestational age:
approximate gestational age (in weeks) = placental thicknes...
Placental trophotropism refers to a phenomenon where there is dynamic migration of the placenta at its insertion through gestation. The placenta tends to grow in areas of good blood supply and nutrition and atrophies in areas with poor blood supply and poor nutrition. It may play a role in the d...
There are many tumours that can involve the placenta.
These can be of very different pathology and can include
placental chorioangioma (considered the most common primary tumour of the placenta 1)
placental site trophob...
Placental venous lakes refer to a phenomenon of formation of hypoechoic cystic spaces centrally within the placenta. Finding placental lakes during a second trimester ultrasound scan is not associated with any uteroplacental complication or with an adverse pregnancy outcome. They can, however, b...
Placentomegaly is a term applied to an abnormally enlarged placenta.
It can be associated with number of maternal and fetal disorders which include:
chronic intrauterine infections
Polycystic ovarian syndrome (PCOS), recently referred also as hyperandrogenic anovulation, is a chronic anovulation syndrome associated with androgen excess.
The diagnosis is made on the combined clinical, biochemical and sonographic grounds. The revised 2003 ASRM/ESHRE Rotterdam consensus cri...
Getting a film with polycystic ovarian syndrome in a subfertile patient is one of the many exam set-pieces that can be prepared for.
Transabdominal and transvaginal pelvic ultrasound show an anteverted uterus with a normal size. There is diffuse thickening of the endometrium to 17...
Polycystic ovaries (PCO) is an imaging descriptor of a particular type of change in ovarian morphology. A proportion of women with polycystic ovaries will have the polycystic ovarian syndrome (PCOS), which in turn requires additional clinical, as well as biochemical, criteria. Otherwise PCO can ...
Polydactyly refers to the situation where there are more than the usual number of digits (five) in a hand or foot. It can be broadly classified as:
pre-axial polydactyly: extra digit(s) towards the 1st digit (radially)
post-axial polydactyly: extra digit(s) towards 5th digit (ulnar)
Polyhydramnios refers to a situation where the amniotic fluid volume is more than expected for gestational age.
It is generally defined as:
amniotic fluid index (AFI) >25 cm
largest fluid pocket depth (maximal vertical pocket (MVP)) greater than 8 cm 6: although some centres particularly in A...
Polysyndactyly refers to the combined presence of polydactyly as well as syndactyly involving either the hands or feet.
Polysyndactyly can be associated with a number of syndromes which includes:
type I: Noack syndrome
type II: Carpenter syndrome (typically...
Popcorn calcification refers to amorphous calcifications often with rings and arcs that resemble popped corn kernels. This type of calcification may be seen in many radiological settings including 1:
chondroid lesions (e.g enchondroma, chondrosarcoma)
Post-ablation tubal sterilisation syndrome (PATSS) is a recognised delayed complication seen in patients who have undergone both endometrial ablation and tubal sterilisation. It has been reported in 6-8% of these patients and occurs when bleeding from residual endometrium is obstructed due to su...
Post-axial polydactyly refers to polydactyly where the additional digit is on the ulnar margin of the hand, or lateral to the 5th toe.
Post-axial polydactyly is more common than pre-axial polydactyly, with an estimated incidence of 1 in 3000.
Post dates fetus is when there is prolonged gestation when the fetus remains in-utero beyond 2 weeks beyond expected date of delivery (>42 weeks gestation).
The reported frequency is at approximately 3-12% of pregnancies.
Posterior urethral valves (PUVs), also referred as congenital obstructing posterior urethral membranes (COPUM), are the most common congenital obstructive lesion of the urethra and a common cause of obstructive uropathy in infancy.
Posterior urethral valves are congenital and only...
Post partum haemorrhage (PPH) refers to uterine bleeding after delivery and remains one of the major worldwide causes of maternal mortality.
A post partum haemorrhage can be board classified as primary or secondary.
Primary post partum haemorrhage
This is the most ...
The Potter sequence is a constellation of findings demonstrated postnatally as a consequence of severe, prolonged oligohydramnios in utero.
It consists of:
pulmonary hypoplasia: often severe and incompatible with life
growth restriction (IUGR)
abnormal facies (Potter f...
Predominantly solid ovarian neoplasms account for a minority of ovarian neoplasms. They include a wide pathological spectrum:
epithelial tumours: ~28% of all solid ovarian tumours 1
germ cell tumours: ~22% 1
ovarian teratoma: noncystic type
sex cord / s...
Premature rupture of membranes (PROM) refers to a rupture of the amniotic sac and chorion (membranes) occurring prior to the onset of uterine contractions. When this occurs prior to 37 weeks it is then termed a pre term premature rupture of membranes (PPROM). By this definition, PROM is classifi...
Primary fallopian tube carcinoma (PFTC) is an extremely rare malignancy that arises from the fallopian tube. They account for ~1 (0.2-1.1)% all gynaecological malignancies (least common of all gynaecological malignancies 3).
The estimated incidence is at ~3-4 per million women 3. ...
The staging used for primary fallopian tubal carcinoma is the FIGO system and is as follows:
stage I: limited to fallopian tubes
stage Ia: limited to lining of one fallopian tube (intraluminal)
stage Ib: limited to inner linings of both tubes (intraluminal)
stage Ic: invasion beyond the inne...
A primary fetal hydrothorax (PFHT) is a rare situation and refers to a primary accumulation of fetal pleural fluid without any underlying abnormality. It can present with a wide spectrum of severity and can be uni or bilateral.
The estimated prevalence is at ~ 1:10,000-15,000 preg...
Primary ovarian lymphoma (POL) refers to involvement of the ovary with lymphoma but without involvement of any other site. It is an extremely rare yet well recognised condition.
POL accounts for ~1.5% of ovarian tumours 5.
The rarity of this condition is probably contr...
Primary peritoneal neoplasms comprise of an uncommon group of heterogenous entities.
The list includes:
primary (malignant) peritoneal mesothelioma
primary perioneal multicystic mesothelioma
primary peritoneal well differentiated papillary mesothelioma
A primary serous papillary carcinoma of the peritoneum (PSPCP) is an extremely rare primary peritoneal tumour.
They usually present in postmenopausal women.
Patients tend to present with non-specific complaints such as abdominal pain, anorexia, and abdomina...
Primary vaginal carcinoma, although being a rare overall, is still the 5th commonest gynaecological malignancy. A primary vaginal carcinoma is defined as a neoplasm that arises solely from the vagina with no involvement of the external os superiorly or the vulva inferiorly, the importance of thi...
Primary vulval cancer is a rare gynaecological malignancy that originates from the vulva.
It accounts for ~3-5% of female genital tract malignancies and typically presents in postmenopausal patients peaking around the age of 65-70 years of age 1.
The commonest histolo...
Proboscis is a rare congenital anomaly where an anterior appendage-like structure is seen projecting from the midline fetal face/forehead. Depending on the exact location, this has further been classified into various subtypes (e.g. interorbital proboscis).
Prolonged rupture of membranes refers to a rupture of membranes lasting longer than 18-24 hours (i.e. between time of rupture and time of delivery) 1-2. This situation can occur in either the term or pre-term newborns where in the latter case it is also termed prolonged preterm rupture of membra...
Psammoma bodies are round microscopic calcific collections. It is a form of dystrophic calcification. Necrotic cells form the focus for surrounding calcific deposition. They have a lamellated concentric calcified structure, sometimes large enough to be seen on CT.
Psammoma bodies are found in ...
A pseudodysraphism refers to the splayed appearance of a normal spine created due to excessive craniocaudal angulation during sonographic evaluation. This can erroneously lead to the diagnosis of a spinal neural tube defect.
Pseudo Meigs syndrome refers to a clinical syndrome of pleural effusion, ascites associated with an ovarian tumour that is not a fibroma or a fibroma-like tumour.
Entities that have been reported to result in pseudo Meigs syndrome include
colon carcinoma metastas...
Pulmonary hypoplasia (PH) refers to deficient or incomplete development of parts of the lung. It can develop as a result of a number of other in utero anomalies.
The true prevalence is not well known (1.4% of all births according to Knox et al. 13), but in cases of premature ruptu...
A pure primary ovarian choriocarcinoma is an extremely rare form of ovarian malignancy. It falls under the sub category of ovarian germ cell tumours.
They are thought to to account for less than 1% of ovarian tumours.
They are a type of non gestational choriocarcinoma....
Pyometrium refers to infection of the endometrial cavity with resulting expansion due to accumulated pus (pyometra).
The post-menopausal demographic are most commonly affected due to the association with uterine malignancy.
endometritis / pelvic inflammatory disease
Pyosalpinx refers to a Fallopian tube that is filled, and often distended, with pus.
A pyosalpinx often tends to be a complication of background pelvic inflammatory disease (PID). Inflammation results in tubal and peritubal adhesions with superimposed obstruction of the fimbrial end....
Retained products of conception (RPOC) refer to the persistence of placental and/or fetal tissue in the uterus following delivery, termination of pregnancy or a miscarriage.
Retained products of conception complicate ~1-5% of all pregnancies (routine vaginal deliveries 12).
A retroverted uterus is a normal variation of female pelvic anatomy in which the body of the uterus is tilted backwards (usually leans forward, i.e. anteverted) on itself to match the isthmus of the neck and lower uterine segment. There are variable grades of uterine retroversion.
Rhizomelic dwarfism is a type of dwarfism where the dominant feature is proximal (i.e. femoral, humeral) limb shortening.
The following conditions fall under the heading of rhizomelic dwarfism 3
rhizomelic chondrodysplasia punctata
Right iliac fossa mass is a common clinical presentation and has a range of differentials that need to be excluded. Radiology plays an important role in this differentiation.
The ring of fire sign, also known as ring of vascularity, signifies a hypervascular lesion with peripheral vascularity on colour or pulsed Doppler examination of the adnexa due to low impedance high diastolic flow 1.
This sign can be seen in:
corpus luteum cyst (more commonly)
The risk of malignancy index (RMI) in ovarian tumours is a validated clinical tool used for risk stratification of ovarian lesions, to guide further management 1-3.
The score incorporates the patient's menopausal status (M), ultrasound features of the lesion (U), and the serum C...
Robinow syndrome is a rare heterogenous genetic disorder with at least two distinct forms.
The syndrome can affects several systems which include:
mesomelic limb shortening: mesomelia
characteristic facies anomalies
A Rokitansky nodule or dermoid plug refers to a solid protuberance projecting from an ovarian cyst in the context of a mature cystic teratoma. It often contains calcific, dental, adipose, hair and/or sebaceous components 1.
History and etymology
It is named after Carl von Rokitansky (1804-187...
Rothmund-Thomson syndrome (RTS) is an extremely rare autosomal recessive disorder with heterogeneous clinical features.
It is characterized by many features which include:
poikiloderma: characteristic rash, typically develops in infancy
sparse hair, eyelashes, and/or eyebro...
Rubinstein-Taybi syndrome (RTS) is a very rare genetic multi-system disorder primarily characterised by mental retardation, broad and often angulated thumbs and halluces, and distinctive facial features.
The estimated incidence is 1 in 100,000-125,000 live births 5.
Ruptured ovarian cysts are one of the most common causes of acute pelvic pain in premenopausal women. The sonographic appearance depends on whether a simple or haemorrhagic ovarian cyst ruptures, and whether the cyst has completely collapsed. The most important differential consideration is a ru...
A rupture of membranes (ROM) or amniorrhexis is a term used during pregnancy to describe a rupture of the amniotic sac. This can occur as part of normal birth (or "spontaneously") if it occurs at full term at the onset of, or during, labor. It is also colloquially known as "breaking water."
Russell-Silver dwarfism is a very rare syndrome characterised by:
intrauterine growth restriction: tends to give an asymmetrical IUGR
postnatal growth restriction
relatively large calvarium: pseudohydrocephalus
clinodactyly/clinobrachydactyly of the small finger
a typical triangular type fa...
Sacrococcygeal teratoma (SCT) refers to a teratoma arising in the sacrococcygeal region. The coccyx is almost always involved 6.
It is the commonest congenital tumour in the fetus 11 and neonate 3. The incidence is estimated at ~1:35000-40000. There is recognised female predilecti...
SADDAN syndrome is an acronym for (severe achondroplasia with developmental delay and acanthosis nigricans). It is an extremly rare condition and as the name stands comprises of skeletal brain and cutaneous anomalies.
It (like achondroplasia) also results from a mutation i...
Salpingitis refers to inflammation of the fallopian tube, it can be a part of pelvic inflammatory disease.
salpingitis isthmica nodosa
Salpingitis isthmica nodosa (SIN), sometimes also referred to as perisalpingitis isthmica nodosa - PIN, refers to nodular scarring of the fallopian tubes. In very early stages, the tubes may appear almost normal. As scarring and nodularity progress, the changes become more radiographically appar...
Sampson syndrome refers to a type of superficial endometriosis, where multiple superficial plaques may be seen scattered in the peritoneum and pelvic ligaments.
The patient may present with non-specific abdominal pain.
At laparoscopy, they are typi...
A sandal gap deformity, also known as hallux varus, is an imaging observation in antenatal ultrasound (typically second trimester) where there is an expanded first interspace, i.e. the gap between the great toe of the foot from the rest of the toes (likened to the gap caused by a sandal).
Scar endometriosis is a term given to endometriosis occurring in a Caesarian section scar. It can be located at the skin, subcutaneous tissue, rectus muscle/sheath, intraperitoneally, or in the uterine myometrium (within uterine scar).
The reported incidence of abdominal scar endo...
Sclerosing stromal tumour (SST) of the ovary is a rare ovarian neoplasm. It is considered a subtype of ovarian sex cord / stromal tumour and is included in the fibroma-thecoma group of ovarian tumors 9.
It occurs predominantly in young women, peaks around 2nd to 3rd decades of lif...
Secondary involvement of the ovary with lymphoma is more common than primary ovarian lymphoma. It usually occurs a late manifestation of an advanced systemic disease, and are almost always of the non-Hodgkin type.
Semilobar holoprosencephaly is a subtype of holoprosencephaly (HPE) characterised by an incomplete forebrain division. It is intermediate in severity, being worse than lobar holoprosencephaly and better than alobar holoprosencephaly.
Please refer on the general article of holopros...
Serous inclusion cysts of the ovary are benign cysts typically seen in postmenopausal women. They are typically small (i.e. less than 5 cm), smooth walled and have no septations or solid components. They can alter through time and often disappear.
Sex cord / stromal ovarian tumours are a subtype of ovarian tumours and account for 8-10% of all ovarian tumours. They arise from two groups of cells in the ovary:
primitive sex cords: coelomic epithelium
The group of tumours includes
ovarian fibroma-thecoma spectrum
Shading sign is an MRI finding typically seen in an endometrioma. It may also be seen with some endometrioid tumours (e.g endometrioid carcinoma of the ovary)
It helps to distinguish endometriomas from other blood-containing lesions (e.g. haemorrhagic corpus luteum cysts), with a sensitivity of...
Shorted fetal femur is a morphological descriptor and is usually defined when the femoral length falls below the 5th centile for gestational age (some define it when its under the 2.5th centile 5) or less than 0.91 predicted by the bi-pareital diameter. It can occur in isolated or in association...
Shortening of the uterine cervical canal as the name implies refers to an abnormal shortening of the uterine cervical length. It is considered a sign of cervical incompetence in pregnancy and can lead to premature delivery.
primary (i.e. congenital/idiopathic)
A short maxillary length can result from many congenital and acquired causes. If seen in an antenatal ultrasound scan, it is often considered to have a high association with trisomy 21 1.
Many conditions that can cause midfacial hypoplasia will result in a short maxillar...
Short rib polydactyly syndrome(s) (SRPS) comprise a rare group of severe osteochondrodysplasias. There are four major recognised types present:
type I: Saldino-Noonan type
type II:: Majewski type
type III: Verma-Naumoff type
type IV: Beemer-Langer type
There may also be other very rare type...
SHORT syndrome refers to an acronym which primarily comprises of the following features:
S: short stature
H: hyperextensibility of joints and/or inguinal hernia
O: ocular depression
R: Rieger anomaly
T: teething delay
In a addition to these there can be numerous associated minor features w...
Short umbilical cord has been variably defined. Considering the mean length of the umbilical cord is 50-70 cm 1-2, a short cord in absolute terms is usually taken as one that is under 35-40 cm in length at term 1-2.
Recognised associations include
Sirenomelia (also known as the mermaid syndrome) is a rare congenital malformation characterised by the fusion of lower limb structures.
The estimated incidence is at ~1 in 60,000-70,000 of pregnancies 9. There may be greater male predilection (somewhat paradoxical given the usage...
A Sister Mary Joseph nodule is a metastatic lesion involving the umbilicus. The most common primary source is an intra-abdominal adenocarcinoma.
Umbilical metastases are uncommon, reportedly present in 1-3% of all intra-abdominal and/or pelvic malignancy 7.
Small cell carcinoma of the cervix is a rare histological subtype of carcinoma of the cervix.
Small cell carcinoma is thought to account for ~0.5-6% of all uterine cervical cancers 3.
It is a type of neuroendocrine tumour and is similar to pulmonary small cell carcin...
Snowstorm sign may refer to:
snowstorm sign: complete hydatiform mole (ultrasound)
snowstorm sign: extracapsular breast implant rupture (ultrasound)
snowstorm sign: thyroid pulmonary metastases (chest radiograph)
Soft-tissue sarcomas are a heterogeneous group of malignant tumours of mesenchymal origin (sarcoma) that originate from the soft tissues rather than bone. They are classified on the basis of tissue seen on histology. The commoner sarcomas in the adult and paediatric population are listed below.
Obstetric and gynaecological ultrasound is rampant with numerous cut off values. Some of these get revised over the years. The following list is a useful aid to refer to and revise.
rate of increase of a mean sac diameter per day in early pregnancy
generally accepted value for a th...
Sonohysterography, also referred as saline induced sonohysterography (SIS), is an ultrasound technique that better characterises the uterine cavity and endometrium. It is particularly useful for evaluation of endometrial polyps.
fertility evaluation / recurrent pregnancy loss
Specialised teratomas of the ovaries are a rare subtype of ovarian teratomas where there is a monodermal differentiation of tissue element. Therefore they usually contain only endodermal, ectodermal or mesodermal elements.
Entities that are classified under this sub group include:
The squamo-columnar junction (SCJ) of the cervix refers to a transitional area between squamous epithelium of the vagina and the columnar epithelium of the endocervix. This shifts in location through age from being more external to internal. Carcinoma of the cervix develops almost exclusively wi...
Squamous cell carcinoma (SCC) of the cervix is the most common histological subtype of cervical cancer and accounts for 80-90% of cases.
Most cervical squamous cell carcinomas grow at the squamocolumnar junction (SCJ). In younger women, the SCJ is located outside the external uterine...
Squamous cell carcinoma (SCC) of the ovary is extremely rare and usually arises in a mature cystic ovarian teratoma 2. As only parts of the lesion are composed of malignant tissue, it is difficult to diagnose malignant transformation of a teratoma preoperatively, unless invasion into adjacent st...
Stenosis of the uterine cervix is the pathologic narrowing of the uterine cervix. The term cervical stenosis is clinically defined as cervical narrowing that prevents the insertion of a 2.5 mm wide dilator.
One-fifth of patients have a history of exposure to diethylstilbestrol whi...
String of pearls sign can refer to:
string of pearls sign on an abdominal radiograph of fluid-filled dilated small bowel loops
string of pearls sign on ultrasound in polycystic ovarian syndrome
string of pearls sign for angiographic appearances in fibromuscular dysplasia
Struma ovarii tumour is a subtype of an ovarian teratoma and is composed entirely or predominantly of thyroid tissue and containing variable-sized follicles with colloid material.
It accounts for 0.3-1% of all ovarian tumours and ~3% of all mature cystic teratomas 1.
Subendometrial cysts can arise from several pathologies which include
tamoxifen-associated endometrial changes 1,3
The subendometrial halo is a hypoechoic stripe formed at the innermost part of the myometrium directly bordering the endometrium. It is important to assess its continuity in order to rule out myometrial invasion in endometrial carcinoma.
Getting a film with submucosal fibroid in the exam is one of the many exam set-pieces that can be prepared for.
Transabdominal and transvaginal pelvic ultrasound scans show an anteverted uterus with endometrium that is 7 mm wide and has a trilaminar appearance indicative of the pe...
Submucosal leiomyomas of the uterus refer to a subtype of uterine leiomyoma that primarily projects into the endometrial cavity. They are least common albeit the most symptomatic type of leiomyoma.
Submucosal leiomyomas can be a common source of abnormal uterine bleeding ...
Subserosal uterine leiomyoma is a subtype of uterine leiomyoma that often exophytically projects outwards from a subserosal location. While its exact definition may vary, a leiomyoma is often called subserosal if >50% of the fibroid protrudes out of the serosal surface of the uterus 2. They can ...
The superficial perineal pouch is an anatomic space below the perineal membrane in the urogenital triangle of the perineum.
The superficial perineal pouch is inferior (superficial) to the perineal membrane in the urogenital triangle, anterior to the transverse line between the is...
Surgical haemostatic material is used to control bleeding intraoperatively and is hence frequently voluntarily left in the operative bed, not to be confused with a gossypiboma which is foreign material left by mistake. It can mimic an abscess on imaging studies. Various types are available, the ...
Syndactyly refers to a congenital fusion of two or more digits. It may be confined to soft tissue (soft tissue syndactyly / simple syndactyly) or may involve bone (bony syndactyly / complex syndactyly).
The overall estimated incidence is at ~1 per 2500 to 5000 live births 6,8. The...
T2 dark spot sign is an MRI appearance of endometriomas seen as a result of chronic haemorrhage. The sign is useful in differentiating a solitary endometrioma from a functional haemorrhagic ovarian cyst, as both might show high T1 signal with T2 shading.
The T2 dark spot, described in the sign...
Tamoxifen has pro-oestrogenic effects on the endometrium and thus is associated with an increased prevalence of:
endometrial polyps: occurs in ~8-36% of women in treated 8
endometrial hyperplasia: occurs in ~1-20% of women treated ref
cystic endometrial atrophy