Gyn Obs Flashcards

Question

A 31-year-old woman presents with dysfunctional uterine bleeding. Transvaginal ultrasound shows a hypoechoic vascular mass in the cervix. The mass bulges into the endocervical canal and parametrium. On MRI, there is a cervical mass lesion which returns high signal on T2 and poorly defined margins beyond the cervical stroma. The most likely diagnosis is? [B5 Q6] (a) Endometrial carcinoma (b) Cervical carcinoma (c) Focal adenomyosis (d) Cervical lymphoma (e) Prolapsed submucosal fibroid

Answer 1

**Cervical carcinoma** Cervical carcinoma typically presents with bleeding and pelvic pain. MRI is the imaging of choice which shows high signal on T2 images.

Answer 2

**Cervical carcinoma** Cervical carcinoma is high signal as compared to fibrous cervical stroma on T2 and enhances with contrast.

Answer 3

**Stage T2b ** Stage 1 lesions are confined to cervix. Stage 2a lesions involve the vagina, while 2b tumours invade the parametrium as well. Stage 3 lesions involve the lower third of vagina and/or the lateral pelvic wall. Stage 4 tumours are seen to invade other surrounding organs such as the bladder and rectum.

Answer 4

**Endometriosis** Endometriosis can be found in surgical scars or needle tracts. Most cases of subcutaneous endometriosis occur in Pfannenstiel incisions. Abdominal wall endometriosis is thought to occur in up to 1% of cases. Clinically it presents as a cyclical painful lump and can arise many years after surgery.

Answer 5

**Recommend a repeat trans-abdominal ultrasound in 6 weeks’ time**. At ultrasound, a functional ovarian cyst is typically anechoic with a thin, smooth wall and posterior acoustic enhancement. Regardless of size, these cysts are unlikely to be malignant. A unilocular cyst greater than 3 cm in a premenopausal or greater than 5 cm in a postmenopausal female patient should be rescanned in approximately 6 weeks. Sonographic findings which increase the likelihood of malignancy include wall thickening, solid elements, septations, and abnormal blood flow. If a cyst displays any of these features or increases in size on interval scanning, further steps such as Ca-125 measurement or MRI may be warranted.

Answer 6

**Repeat transvaginal ultrasound scan in 4 months** The Risk of Malignancy Index (RMI) is used to stratify the likelihood of an incidentally identified ovarian cyst being malignant. The RMI is the product of the ultrasound score, the CA-125 level and the score assigned according to menopausal status. Low-risk cysts can be managed conservatively. A cyst below 5cm in diameter that is unilocular, unilateral and echo-free, and has no solid parts or papillary formations has a risk of malignancy of less than 1%, and a 50% chance of resolving spontaneously in 3 months.

Answer 7

**Multiple small peripheral rounded high T2WI signal areas with hypointense central stroma in both ovaries**. The clinical features suggest polycystic ovarian syndrome (PCOS). The diagnosis is based on hormonal imbalance and patients often show an abnormality in the ratio of luteinizing hormone to follicle stimulating hormone. The MRI findings are those described, with multiple small peripheral cysts with low signal central stroma. MRI is not specific or sensitive, and 25% of patients with PCOS can have normal appearing ovaries. Multiple small, T2WI hyperintense cysts have been seen in patients with anovulation, medication-stimulated ovulation, or vaginal agenesis. The other descriptions are associated with infertility, but not particularly hirsutism or obesity. Option A describes bilateral hydrosalpinx. Option D describes a unicornuate uterus, which is associated with the poorest foetal survival among all uterine anomalies. Option E describes adenomyosis and using a junctional zone thickness of 12 mm or above optimizes the accuracy of MRI for this diagnosis.

Answer 8

**Ovarian volume >10 ml when no follicles measuring over 10 mm in diameter are present** Diagnosis of polycystic ovary syndrome should not be made on imaging findings alone; clinical and biochemical studies must be obtained. The **diagnosis** can be supported when one or more of the following ultrasonographic features are demonstrated: Radiopaedia: **1. Follicle number per ovary (FNPO) >20** or **2. Follicle number per section (FNPS) >10** or **3. Ovarian volume >10 ml when no corpora lutea or dominant follicles measuring over 10 mm in diameter are present.** If a follicle >10 mm is present, then the volume should be recalculated on a repeat scan when the ovary is quiescent to prevent overestimation of the ovarian volume.

Answer 9

**Ovarian hyperstimulation syndrome** Ovarian hyperstimulation syndrome is more commonly seen with human menopausal gonadotrophin therapy but can also be seen with clomiphene. Severe complications relate to volume depletion, such as hypovolaemia, oliguria, electrolyte imbalance and thromboembolic events. Intra-abdominal haemorrhage is also reported.

Answer 10

**Polycystic ovarian disease** Polycystic ovarian disease is diagnosed by clinical, biochemical and ultrasound findings. Clinically, oligomenorrhoea, hirsutism and obesity are features. Luteinizing hormone is increased as is the luteinizing hormone: follicle-stimulating hormone ratio. Androgen levels are increased. Sonographic findings vary from normal-looking ovaries through hypoechoic ovaries without individual cysts to multiple, 5mm or more, peripherally located cysts in bilaterally large ovaries.

Answer 11

**Stein–Leventhal syndrome** Also known as polycystic ovary disease, patients may have reduced fertility, hirsutism, obesity, and menstrual irregularities. The ovaries are generally enlarged with multiple small follicles measuring less than 10 mm, usually subcapsular.

Answer 12

**Endometriotic cyst**. Also known as a chocolate cyst, the methaemoglobin within the lesion causes T1 shortening, resulting in increased signal on the T1WI sequence. This high signal remains and becomes more conspicuous on the T1WI with fat saturation sequence. Endometriosis is characterized by the presence of tissue resembling endometrium outside the uterus. The ovaries are the most commonly involved site, and endometriotic cysts usually have a thick fibrotic wall with chocolate-coloured hemorrhagic material. An endometriotic cyst may be high or low signal on T2WI sequences. Chronic cyclical haemorrhage and increased viscosity of the cyst material will produce T2 shortening, leading to the low signal, or ‘T2 shading’. The patient usually presents with cyclical pain. The cysts have a propensity for multicentric growth and are often associated with fibrous adhesions. These latter features increase the MR sensitivity. Small peritoneal implants of endometriosis may be identified elsewhere and their conspicuity is increased by the use of fat saturation techniques. Endometroid and clear cell carcinoma of the ovary are malignancies associated with endometriosis and these represent 17.5 and 7.4% of ovarian carcinomas, respectively. Chocolate cysts with multiple locules, mural foci, or nodules within the cyst are suspicious for malignancy and contrast should be administered if this appearance is seen. The findings in this question are not consistent with a follicular cyst, which would show low T1WI and high T2WI signal. Brenner tumours show low T2WI signal due to their abundant fibrous content and calcification, but also low T1WI signal. Fibro-thecomas show intermediate T1WI signal and usually low (although sometimes it can be mixed high and low) T2WI signal. They sometimes show associated uterine enlargement, as they may be oestrogenic.

Answer 13

**Follicular cyst** These are common ovarian masses that result from a failure of the mature Graafian follicle to rupture and release ova. Typically, they are smooth, thin walled, unilocular anechoic cysts that show spontaneous regression within four to six weeks. They may undergo haemorrhagic change producing internal echogenic material. They are generally larger than 2.5 cm and may occasionally grow up to 10 cm.

Answer 14

**It is normal for a premenopausal ovary but large for a postmenopausal ovary** Normal ovarian volume is less than 18cm³ before the menopause and less than 8cm³ postmenopausal. The volume can be estimated by multiplying the three diameters and dividing by two.

Answer 15

**Endometrioma** MRI is highly sensitive and specific in the diagnosis of endometrioma. The endometrioma returns high signal on T1 and T2 and STIR sequences due to blood products. On ultrasound the lesion may show diffuse homogenous low-level internal echoes (haemorrhagic debris). Other features may include septations or echogenic material suggesting a clot.

Answer 16

**Endometriosis** Cystadenocarcinoma, dermoid abscess, endometriosis and ectopic pregnancy are examples of cystic ovarian masses.

Answer 17

**Rupture may lead to pseudomyxoma peritonei** 20% of ovarian tumours are mucinous. These are the second most common benign epithelial neoplasm after serous ovarian neoplasia. Mucinous cystadenomas account for 80% and are multiloculated cysts with numerous septae, occurring in the third to fifth decades.

Answer 18

**Endometroid tumour** Benign serous cystadenoma is bilateral in 20% of cases, benign mucinous cystadenoma in 5%, malignant serous cystadenocarcinoma in 50% and malignant mucinous cystadenocarcinoma in 25%. **Endometrioid ovarian tumours frequently bilateral (30–50%) but they are also often (30%) found with concomitant endometrial adenocarcinoma.**

Answer 19

**Liver parenchymal deposits** Liver capsule deposits are stage T3/III. The pleural effusion cannot be regarded as M1/IV, because it requires positive cytology for this. Any involved regional nodes give stage IIIc and include obturator, common, internal and external iliac, laterosacral, inguinal and para-aortic.

Answer 20

**CT of the abdomen and pelvis with oral and IV contrast** Plain chest radiograph may be added to this as a routine, but chest CT would be requested only with an additional reason to do so. MRI of the ovaries can be helpful in characterizing ovarian masses where ultrasound scan and CA-125 are equivocal. There may be a role for PET/CT in defining disease extent, but cystic tumour deposits, particularly when they may be on or close to bowel or associated with ascites, present a challenge for this technique.

Answer 21

**Malignant Ovarian Neoplasm** Features of an ovarian cyst that suggest malignancy are thick irregular walls and thick septations (>2mm), large overall size, solid elements and, on Doppler scan, a high peak systolic velocity and low-impedance diastolic flow. Together, these give a resistive index (RI) of <0.4 and a pulsatility index (PI) of <1.

Answer 22

**Ovarian carcinoma** Malignant ovarian tumours commonly have solid and cystic components. The solid component has neovascularisation demonstrating a characteristic waveform with a low resistive index.

Answer 23

**Ovarian fibroma** The condition described is Meigs syndrome. This occurs in about 1% of ovarian fibromas but is characterised by a large fibroma, ascites and a pleural effusion (typically right-sided). Ascites and effusion resolve after tumour resection. Fibromas are benign stromal tumours composed of fibrous tissue. On ultrasound they are typically solid hypoechoic lesions with posterior acoustic enhancement.

Answer 24

**Granulosa cell tumour** Granulosa cell tumours are the most common ovarian tumours with oestrogenic manifestations that are classified as sex-cord-stromal tumours. They are subdivided into adult and juvenile types. The juvenile form affects prepubertal children and causes pseudoprecocity. In about a third of cases Sertoli–Leydig cell tumours cause virilisation. Thecomas are oestrogen-producing tumours but more than 80% occur in postmenopausal women. Immature teratomas are extremely rare but do occur in children. Elevated alpha-fetoprotein is found in up to 65% of cases. Sclerosing stromal tumours usually affect women younger than 30 years of age and a few cases have shown androgenic or oestrogenic manifestations. They are also known as hypervascular tumours which show early peripheral enhancement with centripetal progression.

Answer 25

**Variable imaging appearances are recognized from uniloculated cystic masses to solid masses** Represent 70% of malignant sex cord stromal tumours, but only 2-5% of all ovarian tumours have an unpredictable and indolent course with relapse occurring up to several years after initial diagnosis. The adult subtype accounts for 95% of all GCTs.

Answer 26

Commonly present as Meigs’ syndrome

Answer 27

**Referral for surgery**. The findings are consistent with a mature cystic teratoma or dermoid cyst. They are derived from all three germ cell layers and thus contain fat and may contain desquamated epithelium, skin, hair, and teeth. The classical finding is of high T1WI signal, which suppresses on fat saturation imaging. They can often have a fat–fluid level. The low signal on T2WI may represent tooth or calcification. **Soft-tissue protuberances** represent **Rokintansky nodules or ‘dermoid plugs’** of sebaceous material. Dermoids can be bilateral in 8–25% of cases. The chance of malignant transformation is low, but surgical resection is indicated not just for relief of symptoms, but because of the risk of torsion (in 4–16% of cases) or rupture (rare but can lead to chemical peritonitis). Adjuvant treatment need not be considered unless the case is complicated by malignant transformation.

Answer 28

**Mature cystic teratoma** Mature cystic teratomas (dermoid cysts) account for approximately 15% of all ovarian tumours. They are benign germ cell tumours containing tissues from all three germ cell layers. They most commonly present in younger women of reproductive age (20–40 years) and may be bilateral in up to 25%. They are generally cystic masses that may contain a **pathognomonic distinct hyperechoic mural nodule (dermoid plug/Rokitansky nodule) which project into the cystic lumen and causes posterior acoustic shadowing.** This nodule represents in-growth of solid tissue such as hair or teeth from the tumour wall.

Answer 29

**Carry a poorer prognosis than any other ovarian germ cell tumour** Yolk sac tumours are well-enhanced tumours consisting of mixed solid and cystic tissue with some area of haemorrhage. A ‘bright dot’ sign is recognized; a well-enhanced dilated vessel on the post-contrast image. Yolk sac tumours have a poor prognosis. They account for 1% of ovarian malignancies. They are the second most common malignant germ cell tumour after dysgerminomas.

Answer 30

**Mature cystic teratoma of the ovary** The main differentials for an ovarian mature cystic teratoma (dermoid cyst) are endometriomas and proteinaceous ovarian cysts, which can also have fluid–fluid levels. Fat is frequently demonstrated in a dermoid cyst, but not in these differentials. Fat can be proven by a significant negative attenuation value on CT, or on MRI with chemical shift artefact in the frequency-encoding direction, a gradient echo sequence in which fat and water are in opposite phase or frequency-selective fat saturation sequences. Mature cystic teratoma contains mature tissues of germ cell (pleuripotent) origin. At least two of the three germlines should be represented. Mean patient age is 30 years, younger than for epithelial ovarian neoplasms, and it is the commonest ovarian mass in children. Usually asymptomatic, they can cause abdominal pain or other nonspecific symptoms. They are bilateral in 10% of cases.

Answer 31

**Ovarian dermoid** This is a germ cell tumour which contains skin and dermal appendages. These are diagnosed by characteristic ectodermal contents of hair, teeth fat and bone. Identification of a sebum-fluid level and calcification is diagnostic. There is risk of malignant degeneration, torsion, and rupture.

Answer 32

**Ovarian dermoid** Fibrous lesions in the adnexa are of low signal intensity on MRI. Ovarian dermoids return high signal because of their fat content, with signal drop-out on fat suppression images. Other causes of lesions which may return high signal on T1 include endometrioma, mucinous cystic neoplasm, haemorrhagic cysts, and ovarian carcinoma.

Answer 33

**Krukenberg tumours**. The history points towards a GI source, namely gastric carcinoma. Approximately 5–15% of ovarian tumours are metastatic lesions. They are bilateral in 75% of cases. They are often asymptomatic and may present before the primary tumour. They should be considered, along with serous epithelial tumours of the ovary, when bilateral complex ovarian masses are demonstrated. Krukenberg tumours represent ovarian metastases that contain mucin-secreting ‘signet-ring’ cells from colonic or gastric neoplasms. Other primary neoplasms that less commonly metastasize to the ovary are breast, lung, and the contra-lateral ovary (not strictly Krukenberg tumours due to the cell types). Imaging findings in metastatic lesions are nonspecific, consisting of predominately solid components or a mixture of cystic and solid areas. In Krukenberg tumours, there are distinctive findings, including solid components secondary to stromal reaction that are low T2WI and high T1W signal

Answer 34

**Krukenberg’s tumour** Krukenburg’s tumours are metastatic tumours of the ovary. The colon and stomach are the most common primary tumour sites, but other sites, such as the breast, lung, and pancreas, have also been reported. They display characteristic imaging features, including bilateral, sharply marginated oval tumours which preserve the contour of the ovary. Identification of **hypointense solid components on T2** corresponding to areas of dense collagenous stroma is also considered characteristic.

Answer 35

**Ovarian torsion** Ovarian torsion usually presents in the first three decades of life and is predisposed in patients with co-existing ovarian pathology such as follicular cyst. There may be a history of similar episodes indicating intermittent torsion and spontaneous detorsion. Torsion causes venous outflow obstruction and engorgement of the ovary. Eventually arterial supply is compromised, and necrosis ensues. Diagnosis is suggested by unilateral enlargement of a round or oval-shaped ovary containing multiple enlarged peripheral cysts (caused by transudation of fluid into follicles). Free fluid is present in most cases. Peripheral blood flow may be present but may be absent with infarction. Ovarian hyperstimulation can present with abdominal pain and may show an enlarged multicystic ovary associated with ascites. However, the condition usually arises from ovarian hormone stimulation in the setting of infertility. Polycystic ovary syndrome typically presents with menstrual disturbance, obesity, and hyperandrogenism.

Answer 36

**Right ovarian vein thrombosis** The puerperium is a hypercoagulable state, and puerperal endometritis can seed bacteria along the ovarian vein. Eighty percent of thromboses are on the right and 14% are bilateral. Incidence is between 1 in 600 and 1 in 2000 deliveries. On contrast-enhanced CT, a tubular structure with low-density centre and peripheral enhancement is seen. Complications include inferior vena caval thrombosis, pulmonary embolus (25%), septicaemia, metastatic abscess formation, and death (5%).

Answer 37

**Bartholin’s gland cyst**. Bartholin’s glands are located behind the labia minora and their ducts open onto the posterolateral vestibules on each side. The cysts are due to blockage of the ducts and retention of secretions. They are common in reproductive age and are usually cystic in appearance (high T2WI signal). Their T1WI signal is variable and can be high due to mucoid content. They are usually discovered as incidental ﬁndings on imaging for another cause, although they may be palpable or clinically visible. The radiologist should recognize them as a benign pathology. Primary carcinoma of the vagina is rare, as 80–90% of tumours affecting the vagina are due to extension of primary bladder, cervical, vulval, or rectal tumours. Ninety per cent of primary carcinomas are squamous cell carcinoma. The majority occur in elderly women and the two most common presenting complaints are vaginal discharge and bleeding. Squamous cell carcinomas of the vagina are usually of low T1WI and intermediate T2WI signal. As for vulval and cervical squamous cell carcinoma, human papilloma virus (HPV) infection is a risk factor. Urethral diverticula are best seen on T2WI sequences as hyperintense lesions adjacent to or surrounding the urethra: a connection to the urethra is not always seen. They are usually of low signal on T1WI sequences. They predispose to stones (low signal on T2WI sequences) and carcinoma (enhancing on T1W fat saturation post gadolinium). Nabothian cysts are found at the external os of the cervix. They are benign retention cysts that develop secondary to obstruction of endocervical glands. They have high T2WI signal and may have high T1WI signal due to mucinous content. They are usually multiple and measure less than 2 cm. They become clinically relevant when they are mistakenly diagnosed as adenoma malignum, a subtype of mucinous adenocarcinoma of the cervix. A vaginal septum is a low-signal T2WI band. If transverse, it may present in adolescence with primary amenorrhea and abdominal pain, and an abdominal mass if complete. A longitudinal septum is usually asymptomatic and is associated with duplication of the uterus, cervix, or vagina.

Answer 38

**Gartner duct cyst** Gartner’s duct cysts are remnants of mesonephric ducts and have a reported incidence of 1–2%. They are ovoid, thin-walled cysts located at the anterolateral aspect of the upper vagina and generally measure less than 2 cm. They may contain proteinaceous material, making them slightly hyperintense on T1. They may be associated with Herlyn–Werner–Wunderlich syndrome (ipsilateral renal agenesis and ipsilateral blind vagina) and ectopic ureter inserting into the cyst. Bartholin cysts are located at the lateral introitus adjacent to the labia minora. Nabothian cysts are epithelial inclusion cysts which develop in the endocervical canal and are most commonly found in the perimenopausal period. Cervical fibroids and cervical polyps show mainly as solid lesions.

Answer 39

**N1** NX is used when regional nodes cannot be assessed, and N0 when there are no involved regional nodes. N1 denotes ipsilateral involved femoral or inguinal lymph nodes. N2 signiﬁes bilateral regional nodal involvement. All intrapelvic nodes are regarded as metastases and therefore do not inﬂuence the N stage. There is no N3 for vulval cancer.

Answer 40

**Inguinal** The upper two-thirds of the vagina drain to the pelvic nodes, which is of relevance when imaging vaginal cancer. This cancer is uncommon, representing 1–2% of gynaecological malignancy. Eighty-ﬁve percent of cases of vaginal cancer are squamous and 15% are adenocarcinoma. Clear-cell carcinoma is a rare form of adenocarcinoma found in young patients with in utero diethylstilbestrol exposure. Even less common are melanoma, sarcoma and adenosquamous carcinoma occurring as vaginal primaries. The two commonest cell types have different natural histories. Adenocarcinoma tends to involve pelvic and is more likely to involve supraclavicular lymph nodes, while squamous carcinomas are more likely to give rise to liver metastases. They are equally likely to metastasize to the lungs.

Answer 41

**Central high signal within the vagina; focal homogeneous, intermediate-signal mass not breaching the surrounding low-signal vaginal wall** **Vaginal cancer** The **vaginal epithelial layer** and mucus are **bright on T2W images**. This is normally **surrounded by low-signal (ﬁbromuscular) vaginal wall**. **Tumours are typically intermediate signal on T2W images**. If gadolinium is used, cancers often have **early phase enhancement**. Large tumours **may have central necrosis**. T1 tumours do not breach the low-T2-signal vaginal wall, whereas T2 tumours do and extend into the paracolpal fat. T3 tumours reach the pelvic side wall while T4 tumours extend beyond the true pelvis or involve bladder or rectal mucosa.

Answer 42

**Hydrosalpinx** Hydrosalpinx describes a fallopian tube filled with fluid. The fluid is most often anechoic. When the fluid becomes infected, the term pyosalpinx is used and the fluid contents tend to be echogenic. Hydro/pyosalpinx appear as tortuous, well-defined, fluid-filled, oval-shaped structures which extend from the cornua to the ovaries. They are often mistaken for multicystic adnexal masses or septated ovarian cysts due to apparent internal septations. However, the septa, actually the folded wall of the fallopian tube, do not cross the lumen completely. Hydro/pyosalpinx occur most commonly as a result of acute salpingitis and pelvic inflammatory disease (history of early sexual activity/multiple sexual partners). They have also been reported following pelvic surgery. Tubo-ovarian abscesses tend to be multilocular, irregular, thick-walled, complex masses containing debris and internal septations. Internal fluid-fluid levels or gas may also be seen.

Answer 43

**Salpingitis isthmica nodosa (SIN)** SIN is associated with pelvic inflammatory disease and a higher risk of ectopic pregnancy.

Answer 44

**Endometritis** Endometritis is the commonest cause of gas in the uterus. Gas is also seen in the uterus when a submucosal fibroid becomes infected, when necrotic neoplastic tissue is metabolized by bacteria, because of fistula to the gastrointestinal tract, in pyometra secondary to cervix obstruction by cancer, or in cases of gas gangrene due to clostridial infection following septic abortion. Ovarian gas can be seen with infection within an ovarian neoplasm. Numerous gas-filled spaces in the vaginal submucosa and exocervix can occur in pregnancy; this is termed ‘vaginitis emphysematosa’.

Answer 45

**Pelvic inflammatory disease** The patient’s fallopian tubes are occluded, giving bilateral hydrosalpinx. The **commonest cause of proximal or distal tubal occlusion is pelvic inflammatory disease.** Endometriosis, infection following birth or abortion, and tuberculosis are other causes. **Indications for hysterosalpingogram** include: **infertility, recurrent miscarriage**, assessment of the tubes after surgery and assessment of the integrity of a post-caesarean uterine scar. **Contraindications** are **pregnancy**, purulent vulval or cervical discharge, **pelvic inflammatory disease in the preceding 6 months and contrast sensitivity**. Historical contraindications include the immediate post-menstruation phase and recent dilatation and curettage, because of the risks associated with intravasation of oily contrast media.

Answer 46

**Bilateral hydrosalpinx** This is usually a result of continuous secretion of the tubal epithelium into the lumen of a fallopian tube obstructed at two sides. Ultrasound shows undulating or folded tubular structures which are extraovarian. This may be secondary to endometriosis, adhesions, infection, tubal surgery or ectopic pregnancies.

Answer 47

**Succenturiate placenta** Succenturiate placenta is an additional lobule separate from the main bulk of the placenta. The significance of this variant is the rupture of vessels connecting the two components or retention of the accessory lobe with resultant post-partum haemorrhage.

Answer 48

**Double decidual sac sign**

Answer 49

**Double decidual sac sign**. All the other answers are findings in the uterus that may be associated with ectopic pregnancy. In normal pregnancies, TVUS can demonstrate an intradecidual sign approximately 4.5 weeks after the last menstrual period. The intradecidual sign is a small collection of fluid that is eccentrically located within the endometrium and is surrounded by a hyperechoic ring. At approximately 5 weeks, the double decidual sac sign can be visualized. This consists of two concentric hyperechoic rings that surround an anechoic gestational sac in a normal intrauterine pregnancy. The secondary yolk sac may be identified at TVUS at approximately 5.5 weeks. Embryonic cardiac activity should also be visualized at TVUS at approximately 5–6 weeks, when the gestational sac measures at least 18 mm or when the embryonic pole measures at least 5 mm. A pseudogestational sac is a thick decidual reaction surrounding intrauterine fluid and is seen in approximately 10% of ectopic pregnancies. A trilaminar endometrium is formed during the late proliferative phase of the menstrual cycle. When an abnormal pregnancy is suspected based on laboratory results, the absence of a true gestational sac in the presence of a trilaminar endometrium is highly suggestive of ectopic pregnancy. Thin-walled decidual cysts are seen at the junction of endometrium and myometrium and may be seen in both normal and abnormal pregnancies. The thin wall differentiates it from a true gestational sac.

Answer 50

**Ampullary portion of the fallopian tube** The most common site of implantation is the fallopian tube, which accounts for over 90% of ectopic pregnancies. Ovarian and abdominal sites account for only approximately 3% and 1%, respectively. Within the fallopian tube the most common site is the ampulla (73%) followed by the fimbrial and interstitial regions.

Answer 51

**Cystic adenoid malformation** The remainder of the conditions listed above will cause oligohydramnios. Polyhydramnios is defined as amniotic fluid volume >1500–2000 cm³ at term. Most cases are due to maternal factors, with diabetes causing the majority of these. Oligohydramnios is defined as an amniotic fluid volume of <500 cm³ at term; the most common causes include demise of the fetus, drugs, and renal anomalies.

Answer 52

**A crown rump length of 5 mm with no heartbeat detectable on TV scan** In order to assess the presence or absence of a heartbeat accurately on TV scanning, the crown rump length needs to be >6 mm. On TA scanning the crown rump length needs to be >10 mm to accurately assess the absence of a heartbeat. The other options all represent signs of fetal demise. Usually, two qualified ultrasound practitioners are required to assess a fetus if there is concern regarding embryonic demise.

Answer 53

**Pre-eclampsia** **Small placenta:** **Pre-eclampsia** **IUGR** chromosomal abnormality intrauterine infection. **Large placenta: (>5 cm)** Maternal **diabetes** **Chronic intrauterine infection** (e.g. syphilis) **Maternal anaemia** Thalassaemia Twin–twin transfusion syndrome. Fetal chromosomal abnormalities may cause either a large or small placenta.*

Answer 54

**Gadolinium-based contrast material crosses the placental membrane and circulates through the amniotic fluid** The use of MRI in the evaluation of abdominal pain in pregnant patients is increasing. The primary imaging modality of choice, however, remains ultrasound, and MRI is usually reserved for situations where the ultrasound findings are equivocal. The use of gadolinium is not usually necessary in the investigation of abdominal pain in the acute setting and there is little evidence as to its effect on the fetus.

Answer 55

**Patients with a low PI are more likely to become resistant to single drug therapy with methotrexate** Minimal normal UAPI > 1.5. High velocity low impedance waveforms on Doppler are findings in a normal pregnancy but are found in the first and second trimesters in molar pregnancy (far earlier than in a normal pregnancy). Low PI indicates increased AV shunting and are more likely to become resistant to single drug therapy with methotrexate.

Answer 56

**Oestrogens** Uterine cervix length can be measured transabdominally or trans-vaginally. With the former approach, the measurement can be 10% greater than the corresponding transvaginal measurement, because, while the full urinary bladder is a desirable acoustic window, it increases the cervical length. Transvaginally, the normal cervical length is 40±8 mm in the first 14 weeks of gestation, decreasing thereafter by 2 mm per week. A short cervix (measuring ≤ 25 mm at 20 weeks) is associated with an increased risk of premature delivery. Progesterone can be administered to reduce the risk of preterm birth. Oestrogens can be used to maintain pregnancy.

Answer 57

**Snowstorm appearance** The snowstorm appearance is characteristic of molar pregnancies on ultrasound. Molar pregnancies are abnormal growths within the uterus that arise from placental tissue. They are either complete or partial molar pregnancies. A complete molar pregnancy has no fetus or amniotic fluid. Instead, the uterus is filled with hydropic villi, which create the characteristic ultrasound snowstorm pattern. Partial moles, on the other hand, may have some fetal parts and amniotic fluid, but there are still abnormal placental structures. This appearance is the result of the multiple cystic spaces within the placental tissue.

Answer 58

**Crown-rump length** Estimation of gestational age is most accurate in the **ﬁrst trimester**. The **crown–rump length** is used, which has a range of +0.7 weeks. Beyond about 13 weeks, the measurement becomes less reliable as the fetus becomes increasingly ﬂexed. In the very early ﬁrst trimester, the mean gestational sac diameter can be used to estimate gestation age with similar accuracy, but this measurement should not be used once the embryo can be seen. **Biparietal diameter (or alternatively head circumference)** becomes the most reliable measurement in the **second trimester** with an accuracy of +1.2 weeks up to 20 weeks. Femur length is less precise. Abdominal circumference is the least accurate measurement and is generally used only to assess fetal growth and proportionality. Estimation of gestational age becomes considerably less reliable with advancing pregnancy; beyond about 22 weeks, fetal growth becomes the main determinant of fetal size.

Answer 59

**Third (3b)** First-degree perineal tear: involves **skin only**. Second-degree tear: **Perineal muscle** is torn - includes **episiotomy**. Third-degree injury : Involves **anal sphincter** - subdivided into 3 types: * 3a **< 50% of external** sphincter. * 3b **> 50% of external** sphincter. * 3c **Internal sphincter** torn. Fourth-degree tear: Extending into the **anal epithelium**

Answer 60

**Vanishing twin** ‘Vanishing twin’ occurs at less than 13 weeks when one twin is completely resorbed with no residuum evident on ultrasound scan. In foetus papyraceus, one twin is compressed and seen plastered to the adjacent membranes. Fetal death in utero or intrauterine death is signalled by absent heart and somatic movement in the second and third trimesters. Hydrops is excess total body water manifested as extracellular liquid accumulation in tissues and serous cavities. In hydrops of immune origin, antibodies to red blood cells are present.

Answer 61

**Placenta increta** The normal decidua forms a barrier between chorionic villi and uterus, preventing deep invasion of placental material. An underdeveloped or absent decidua permits direct contact of chorionic villi with the myometrium, known as placenta accreta. When the villi invade the myometrium, it becomes placenta increta; if the serosa is penetrated, it is placenta percreta. Diagnosis is difﬁcult on ultrasound scan, but MRI can help. Risk factors are previous caesarean section and myomectomy, multiparity and increasing maternal age. Complications include maternal haemorrhage, premature delivery, intrauterine growth retardation and 5% chance of perinatal death. To protect the mother, balloon catheters can be placed over the internal iliac arteries prior to caesarean delivery.

Answer 62

**Trisomy 18** In 67% of cases of single umbilical artery, there are chromosomal abnormalities. Trisomy 18 has a stronger association than trisomy 13, Turner’s syndrome, or triploidy. Down’s syndrome is not associated.

Answer 63

**Complete placenta praevia** This occurs in 1 in 200 pregnancies, and the incidence rises with increasing maternal age, multiparity, smoking, and previous caesarean section. Delivery is by caesarean section. Third-trimester bleeding occurs in 90% of cases of placenta praevia, with premature delivery and perinatal and maternal death as other complications. A low-lying placenta is one within 2 cm of the internal cervical os. Marginal placenta praevia describes a placental edge up to the os. Partial praevia covers some of the os. From 60% to 90% of patients with placenta praevia in the second trimester have a normal placenta by term because of differential growth of the lower uterine segment.

Answer 64

**Placental abruption 1 week previously** Abruption can be regarded as premature separation of the placenta from the uterine wall secondary to maternal haemorrhage after 20 weeks’ gestation. Manifestations include vaginal bleeding, pain, and disseminated intravascular coagulation. Risk factors include hypertension (pre-eclampsia), previous abruption, smoking, cocaine, leiomyoma, idiopathic factors, fetal malformation, and trauma. Placental abruption is responsible for 15–25% of perinatal deaths. On ultrasound scan, acute haemorrhage appears hyperechoic or isoechoic and may be difficult to distinguish from the adjacent placenta. The haematoma forms a complex hypoechoic collection within 1 week of abruption and usually appears as an anechoic collection within 2 weeks. Placenta membranacea refers to the presence of placental villi in the peripheral membranes.

Answer 65

**Hydrothorax** Major markers for Down’s syndrome include ventriculoseptal defect, cystic hygroma, omphalocele, duodenal atresia, hydrothorax, mild cerebral ventricular dilatation, corpus callosum agenesis, and imperforate anus. The other options given are minor markers.

Answer 66

**Monozygotic; monochorionic monoamniotic** For cord entanglement, the twins must be in the same amniotic sac. Dizygotic twins are non-identical and result from fertilization of two separate ova.

Answer 67

**To ensure that the placenta involutes following delivery and no abscess has developed** The history and imaging features are of extrauterine abdominal pregnancy, which occurs when the fertilized ovum implants directly on the peritoneal surface of the abdomen. This is more likely when the prevalence of pelvic inflammatory disease and ectopic pregnancy is higher. The diagnosis is often established with ultrasound scan. MRI can be used to identify the location and assess adherence to abdominal viscera by the placenta. MR angiography can suggest feeding arteries. MRI at this stage also has a role in detecting fetal anomalies. If the placenta is adherent to abdominal viscera, it is not removed, because this could precipitate catastrophic arterial haemorrhage. Therefore, MRI is performed later to ensure involution of the placenta and exclude abscess formation. Placental adherence is suggested on MRI when it is contiguous with liver or spleen parenchyma, shows circumferential involvement of bowel, or shows continuity with muscle of bowel wall.

Answer 68

**No fetal parts** Gestational trophoblastic disease (GTD) is abnormal proliferation of the trophoblast, which can give rise to a complete or partial hydatidiform mole, invasive mole, or choriocarcinoma. Increasing age and previous GTD are risk factors. Elevation of b-hCG aids diagnosis and is of value in assessing risk of metastatic disease (hence prognosis) and can be used to assess treatment response or detect recurrence. Complete moles have a higher malignant potential than partial moles. A complete mole has no fetal parts and has a 46,XX or, less often, a 46,XY karyotype. A partial mole has fetal parts and a triploid karyotype with 69 chromosomes. Eighty per cent of hydatidiform moles resolve with evacuation, 15% are locally invasive, and 5% give rise to metastatic choriocarcinoma. When GTD is staged, there are no ‘regional’ nodes, and any nodal spread is considered metastatic with a significant worsening of prognosis. On ultrasound, the mole is echogenic but with a vesicular appearance. Fifty per cent of cases are associated with a large, septated theca lutein cyst. On Doppler ultrasound scan, they have prominent associated vessels with low resistance and high peak systolic velocity.

Answer 69

**Herniated midgut into umbilical cord at 9 weeks** All other findings on ultrasound point to complicated pregnancy. **Physiological herniation of bowel is seen from 8–11 weeks**

Answer 70

**Menstruation** Ongoing bleeding at the time of examination is an absolute contraindication to hysterosalpingography. It increases the **risk of infection**, and risks **flushing endometrial tissue into the abdomen**. Recent tubal surgery within last 6 weeks is also a contraindication for this procedure. Other contraindications include pregnancy, immediate pre- and post-menstrual phases, recent untreated pelvic infection, and contrast allergy.

Answer 71

**Utero-ovarian anastomosis is identified in less than 5% of cases**. Uterine arteries are the predominant source of blood supply to the fibroids in most cases. There is considerable variation in the pelvic arterial anatomy, a thorough knowledge of which is essential to carry out uterine artery embolization safely and effectively. Utero-ovarian anastomosis is seen in 10–30% of cases and left-to-right uterine anastomosis in 10% of cases.

Answer 72

**Ovarian dysfunction**. Ovarian dysfunction is a known complication of fibroid embolization. The exact mechanism is not known, but **inadvertent embolization of the ovaries via a uterine–ovarian anastomosis** has been suggested. There is a higher prevalence of uterine–ovarian anastomosis in women over 45 years of age and that puts them at increased risk.

Answer 73

**Pelvic ultrasound scan** The device should be seen within the endometrial cavity on ultrasound scan as an echo-bright structure casting an acoustic shadow. If it is not identified in the uterus on ultrasound scan, then a plain abdominal film is indicated to exclude perforation and migration.

Gyn Obs Flashcards

(97 cards)