benign tumours of the ovary: د. نادية مضر الحلي
ovarian cysts may be physiological or pathological & may arise from any tissue in the ovary.
pathology:
physiological cysts:
physiological cysts are simply large versions of cysts which form in the ovary during the normal ovarian cycle. most are asymptomatic incidental findings at pelvic examination or ultrasound scan. they are an occasional complication of ovulation induction, also may occur in premature female infants & in women with trophoblastic disease.
follicular cyst:
it results from non-rupture of a dominant follicle or failure of atresia in a non-dominant follicle. a follicular cyst may persist for several menstrual cycles & may achieve a diameter of up to 10 cm. intervention may be required if symptoms develop or if the cyst does not resolve after 8-16 weeks. they may produce estrogen causing menstrual disturbance & endometrial hyperplasia.
luteal cyst:
less common than follicular cyst, they are more likely to present with intraperitoneal bleeding, commonly on the right side due to increased intraluminal pressure secondary to ovarian vein anatomy. corpora lutea are not called luteal cyst unless they are more than 3 cm.
benign germ cell tumours:
the commonest ovarian tumours seen in women less than 30 years old. they arise from totipotential germ cells, & may therefore contain elements of all three germ layers (embryonic differentiation). differentiation into extra-embryonic tissues results in ovarian choriocarcinoma or endodermal sinus tumour. when neither embryonic nor extra-embryonic differentiation occurs, a dysgerminoma results.
dermoid cyst (mature cystic teratoma): the most common type. it results from differentiation into embryonic tissues. it account for 40% of all ovarian neoplasms.
a dermoid cyst is usually unilocular, < 15 cm in diameter, in which ectodermal structures are predominant. it is often lined with epithelium like the epidermis & contains skin appendages, teeth, sebaceous material, hair & nervous tissue. endodermal derivatives include thyroid, bronchus & intestine, & the mesoderm may be represented by bone, cartilage & smooth muscle.
occasionally a single tissue may be present, in which case the term monodermal teratoma is used. the classic example is struma ovarii which contains hormonally active thyroid tissue. a small percentage of struma ovarii produce sufficient thyroid hormone to cause hyperthyroidism & 5-10% of them develop into carcinoma.
the majority of dermoid cysts are asymptomatic. a small percentage may undergo torsion or may rupture spontaneously, either suddenly, causing an acute abdomen & chemical peritonitis or slowly causing chronic granulomatous peritonitis. as the latter may also follow intraoperative spillage, great care should be taken to avoid this event & thorough peritoneal lavage must be done if it occurs. during pregnancy rupture is more common due to pressure from the expanding uterus or to trauma during delivery.
about 2% contain malignant component, usually squamous carcinoma in women over 40 years old. again in women less than 20 years 80% of ovarian malignancies are due to germ cell tumours.
mature solid teratoma:
these rare tumours contain mature tissues just like dermoid cyst, but there are few cystic areas.
benign epithelial tumours:
the majority of ovarian neoplasia, both benign & malignant arises from ovarian surface epithelium. so they are derived from the coelomic epithelium from which develop müllerian & wolffian structures. therefore this may result in development along endocervical (mucinous cystadenoma), endometrial (endomerioid) or tubal (serous) pathways or uroepithelial (brenner) lines respectively.
serous cystadenoma:
the most common benign epithelial tumour & is bilateral in 10% of cases. it is usually unilocular cyst with papilliferous processes on the inner surface & occasionally on the outer surface. the epithelium on the inner surface is cuboidal or columnar & may be ciliated. psammoma bodies are concentric calcified bodies which are more frequent in the malignant counterpart. the cyst fluid is thin & serous. they are seldom as large as mucinous tumours.
mucinous cystadenoma:
the second most common epithelial tumours. they are typically large, unilateral, multilocular cysts with smooth inner surface. the lining epithelium consists of columnar mucus-secreting cells. the cyst fluid is thick & gelatinous.
a rare complication is pseudomyxoma peritonei, they result in seedling growths which continue to secrete mucin, causing matting together & consequent obstruction of bowel loops.
endometrioid cystadenoma: these are difficult to differentiate from ovarian endometriosis.
brenner tumours: these rare tumours arise from wolffian metaplasia of the surface epithelium. the tumour consists of islands of transitional epithelium in a dense fibrotic stroma giving a largely solid appearance. the vast majority are benign. the majority are < 2 cm in diameter. some secrete oestrogen & abnormal vaginal bleeding is a common presentation.
clear cell (mesonephroid) tumours: arise from serosal cells showing little differentiation. the typical histological appearance is of clear (hobnail) cells arranged in mixed pattern.
benign sex cord stromal tumours:
constitute a small percentage of benign ovarian tumours. they occur at any age from prepubertal children to elderly, postmenopausal women. many secrete hormones & present with symptoms of inappropriate hormone effects.
granulosa cell tumours: these are malignant tumours but are mentioned here because they are generally confined to the ovary when they present & so have a good prognosis. they grow very slowly. they are largely solid. call-exner bodies are pathognomonic but present in less than half of cases. some secrete oestrogen or inhibin.
theca cell tumours: all are benign, solid & unilateral. present in elderly. oestrogen may be produced in sufficient quantities to cause systemic effects such as precocious puberty, postmenopausal bleeding, endometrial hyperplasia & endometrial cancer. they rarely cause ascites or pleural effusion.
fibroma: these are hard, mobile & lobulated with a glistening white surface. while ascites occur with many of the larger fibromas, meig s syndrome – ascites & pleural effusion in association with fibroma of the ovary- is seen in only 1% of cases.
sertoli-leydig cell tumours: usually of low-grade malignancy, they are rare. many produce androgens, & signs of virilization are seen in three quarters of patients. some secrete oestrogen.
presentation:
• asymptomatic : discovered incidentally.
• pain: acute pain may result from torsion, rupture, haemorrhage or infection. torsion cause sharp, constant pain caused by ischaemia of the cyst. haemorhage cause pain as the capsule is stretched. intraperitoneal bleeding mimicking ectopic pregnancy may result from rupture of the tumour. chronic pain may result if endometriosis is present or due to infection.
• abdominal swelling: noticed only when the tumour if very large.
• pressure effects
• menstrual disturbance
• hormonal effects
• abnormal cervical smear.
differential diagnosis of benign ovarian tumours:
pain
• ectopic pregnancy
• spontaneous abortion
• pelvic inflammatory diseae
• appendicitis
• meckel s diverticulum
• diverticulitis
abdominal swelling
• pregnant uterus
• fibroid
• full bladder
• distended bowel
• ovarian malignancy
• colorectal carcinoma
pressure effects
• urinary tract infection
• constipation
hormonal effects
all other causes of menstrual irregularities, precocious puberty & postmenopausal bleeding.
diagnosis:
history: details of the presenting symptoms & full gynaecological history including the lmp, regularity of the menstrual cycle, any previous pregnancies, contraception, medication & family history (particularly of ovarian, breast or bowel cancer). general symptoms like that of git might indicate gi cancer metastasizing to the pelvis.
examination: include vital signs especially in patients with acute abdomen. examination of the breast, neck, axilla & groin for lymphadenopathy. pleural effusion may occur with some benign ovarian tumours. ankle edema & foot dropinginging may occur due to pressure effect.
abdominal examination: inspection of the abdomen for abdominal distension, dilated veins & male hair distribution in case of androgen secreting tumours. palpation may reveal areas of tenderness, or a mass that arise from the pelvis. positive shifting dullness indicates ascites. bowel sounds should be listened in patient with acute abdomen as their absence in the presence of peritonism is an ominous sign.
bimanual examination is essential for palpating the mass between the vaginal & abdominal hands, its mobility, texture & consistency, presence of palpable lymph nodes in the pouch of douglas. hard, irregular, fixed mass is likely to be invasive.
ultrasound: transabdominal & transvaginal ultrasound are effective in detecting ovarian masses. solid ovarian masses are more likely to be malignant than their cystic counterpart. the use of colour-flow doppler may increase the reliability of ultrasound.
radiological investigations: chest x-ray to detect metastatic disease in the lung or pleural effusion. abdominal x-ray may show calcification in case of benign teratoma. barium enema is indicated if the mass is irregular or fixed, or if there is bowel symptoms.
blood test & serum markers: haemoglobin, wbc, platelet count & cross-match if necessary.
a raised serum ca 125 is strongly suggestive of ovarian carcinoma especially in postmenopausal women. extensive endometriosis may also be associated with elevated level, however it is not as high as seen in malignant disease. the beta-human chorionic gonadotrophin (?-hcg) might be measured to exclude ectopic pregnancy but trophoblastic tumours & some germ cell tumours secrete this marker. oestradiol level may be elevated in women with physiological follicular cyst & sex cord stromal tumours. androgen concentration may be increased by sertoli-leydig tumours. raised alpha-fetoprotein levels suggest a yolk sac tumour.
management: will depend on severity of symptoms, age of patient & therefore the risk of malignancy, and her desire for further children.
asymptomatic patient:
the older woman: women over 50 years of age are far more likely to have a malignancy & have little to gain from the conservative management of a pelvic mass > 5cm in diameter, however more than 50% of small simple cysts will resolve spontaneously. efforts have been made to define criteria that would make unnecessary surgery to be avoided in this older age group
premenopausal women: women aged < 35 years are more likely to wish further children & less likely to have malignant epithelial tumours. ovarian tumours > 10cm in diameter are unlikely to resolve spontaneously
criteria for observation of asymptomatic ovarian tumour:
• unilateral
• unilocular cyst without solid components
• premenopausal women- tumour 3-10 cm in diameter
• postmenopausal women- tumour 2-6 cm in diameter
• normal ca 125 ( < 35mu/ml)
• no free fluid or masses suggesting omental cake or matted bowel loops.
observation include follow up with us after 3 months, if the cyst is the same follow up with us & ca 125 level will be safe.
patient with symptoms:
if the patient presents with severe, acute pain or signs of intraperitoneal bleeding, an emergency laparoscopy or laparotomy will be required. more chronic symptoms of pain or pressure may justify pelvic ultrasound if no mass can be felt.
the pregnant patient:
an ovarian cyst in a pregnant woman may undergo torsion or may bleed. however, an ovarian cyst is usually discovered incidentally at the antenatal clinic or on ultrasound & occasionally at caesarian section.
the pregnant woman with an ovarian cyst is a special case because of the dangers to the fetus of surgery. if the patient presents with acute pain due to torsion or hemorrhage into an ovarian tumor, the correct course is to undertake a laparotomy regardless of the stage of pregnancy. the likelihood of labor ensuing is small however the operation should be covered by tocolytic drugs & performed in a center with intensive neonatal care when possible.
if an asymptomatic cyst is discovered, it is prudent to wait until after 14 weeks gestation before removing it. this avoids the risk of removing a corpus luteal cyst upon which the pregnancy might still be dependant. in the second & third trimesters, the management of an asymptomatic ovarian cyst may be either conservative or surgical. the risk to the mother & fetus of an elective procedure need to be balanced against the chances of a cyst accident, an unexpected malignancy or spontaneous resolution. cysts less than 10 cm in diameter that have a simple appearance on ultrasound are unlikely to be malignant or to result in a cyst accident, & may therefore be followed ultrasonografically: many will resolve spontaneously. if the cyst is unresolved 6 weeks postpartum, surgery may be undertaken then.
ovarian cancer is uncommon in pregnancy, occurring in less than 3% of the cyst. however, a cyst with features suggestive of malignancy on ultrasound or one that is growing should be removed surgically.
management may include a caesarian hysterectomy, bilateral salpingo-oophorectomy & omentectomy.
the prepupertal girl: ovarian cysts are uncommon & often benign. teratoma & follicular cyst are the most common. theca & granulosa cell tumors may secrete hormones. presentation may be with abdominal pain or distension, or precocious puberty, either iso-sexual or hetero-sexual. management depends upon the relief of symptoms, exclusion of malignancy & conservation of maximum ovarian tissue without jeopardizing fertility.
treatment: is usually by surgery. laparoscopy or laparotomy. examination under anaesthesia should be done before the operation is undertaken.
laparoscopic procedures:
indications of laparoscopy:
• uncertainty about the nature of the mass.
• tumour suitable for laparoscopic surgery:
1. age < 35 years.
2. ultrasound show no solid component.
3. simple ovarian cyst.
4. endometrioma.
the advantages are those of laparoscopic surgery in general: less postoperative pain, shorter hospital stay, & quicker return to normal activities. however, the consequences of spillage of cyst content, incomplete excision of the cyst wall & an unexpected histological diagnosis of malignancy are considerable disadvantages.
laparotomy: if there is any possibility of invasive disease, a longitudinal skin incision should be used to allow adequate exposure in the upper abdomen. if wider exposure is required after making a transverse incision, the ends of the wound can be extended cranially to fashion a flap from the upper edge of the wound. a sample of ascetic fluid or peritoneal washings should be sent for cytological examination at the beginning of the operation. it is essential to explore the whole abdomen thoroughly & to inspect both ovaries.
in a young woman < 35 years old an ovarian tumour is unlikely to be malignant thus ovarian cystectomy or unilateral oopherectomy is sensible & safe treatment for those women.
since epithelial cancer is more likely in a woman over the age of 44 years with a unilateral ovarian mass, she is best advised for total abdominal hysterectomy, bilateral salpingo-oopherectomy & infracolic omentectomy.
in women aged 35-44 years treatment should be individualized. if conservative surgery is planned, preliminary hysteroscopy & curettage of the uterus are essential to exclude a concomitant endometrial tumour