Benign ovarian tumors vary in cause depending on a woman's age. Functional cysts are common in young girls and reproductive-aged women, while germ cell tumors occur more in young women and epithelial tumors in older women. Most benign ovarian tumors are diagnosed due to the presence of a pelvic or abdominal mass, pain, or incidentally by ultrasound. Common types include functional cysts such as follicular and corpus luteal cysts, inflammatory cysts such as endometriomas, and germ cell tumors such as dermoid cysts. Benign epithelial tumors like serous and mucinous cystadenomas are more frequent in peri-menopausal women.

1. Benign ovarian tmours
Benign ovarian tumours

2. The causes of benign ovarian tumours will vary
with age.
Functional cysts are common in young girls,
adolescents and women in their reproductive
years.
Germ cell tumours occur more commonly in
young women whereas benign epithelial
tumours occur more commonly in older women.

3. Most benign ovarian tumours will be diagnosed
by the presence of a pelvic/abdominal mass, by
symptoms such as pain (acute pain may
represent torsion of a cyst, rupture or
haemorrhage into it) or incidentally usually on
ultrasound.

4. Causes of benign ovarian cysts
Follicular cyst
Corpus luteal cyst
Theca luteal cyst
Functional
Tubo-ovarian abscess
Endometrioma
Inflammatory
Benign teratomaGerm cell
Serous cystadenoma
Mucinous cystadenoma
Brenner tumour
Epithelial
Fibroma
Thecoma
Sex cord stromal

5. Functional ovarian cysts
The physiological cysts are a persistence of structures found
during normal ovarian function. They are largely asymptomatic
and frequently undergo spontaneous resolution. They may
present with pain and need investigation.
Follicular cysts are particularly likely in patients undergoing
ovulation stimulation. Diagnosis is made when the cyst measures
more than 3 cm (normal ovulatory follicles measure up to 2.5
cm), they rarely grow larger than 10 cm and appear as simple
unilocular cysts on USS.
Treatment depends on symptoms, if asymptomatic they can be
observed and sequential repeat ultrasound can be performed. If
symptomatic, laparoscopic cystectomy may be performed.

6. Corpus luteal cysts occur following ovulation and
may present with pain due to rupture and or
haemorrhage, typically late in the menstrual cycle.
Treatment is expectant, with analgesia.
Occasionally, surgery may be necessary to wash out
the pelvis and perform an ovarian cystectomy.
Theca luteal cysts are associated with pregnancy,
particularly multiple pregnancy, and are often
diagnosed incidentally at routine USS. Most resolve
spontaneously during pregnancy.

7. Inflammatory ovarian cysts
This is usually associated with pelvic inflammatory disease (PID),
and is most common in young women. The inflammatory mass
may involve the tube, ovary and bowel and can be noted as a
mass or an abscess. Occasionally, the tubo-ovarian mass can
develop from other infective causes, for example appendicitis or
diverticular disease.
Diagnosis is based on that for PID, inflammatory markers are
helpful and treatment may include antibiotics, surgical drainage
or excision. Definitive surgery is usually deferred until after the
acute infection due to increased risk of systemic infection and
difficulty with inflamed and infected tissue.

8. • Patients may present with endometriomas,
often known as ‘chocolate cysts’ due to the
presence of altered blood within the ovary.
They can reach 10 cm in size and have a
characteristic ‘ground glass’ appearance on
USS.

9. Ground glass appearance of
endometrioma

10. Germ cell tumours
These are the most common ovarian tumours in young
women, peak incidence is in the early 20s accounting for more
than 50 per cent of ovarian tumours in this age group.
The most common form of benign germ cell tumour is the
mature dermoid cyst (cystic teratoma).
Up to 10 per cent of dermoid cysts can be bilateral. The risk of
malignant transformation is rare (<2 per cent), usually
occurring in women over 40 years.
Dermoid cysts are a combination of all tissue types
(mesenchymal, epithelial and stroma). Any mature tissue type
may be present and often hair, muscle, cartilage, bone or
teeth may be noted. Diagnosis may be incidental, although 15
per cent present acutely with torsion.

11. Dermoid cyst of the ovary

12. Torsion of dermoid cyst.

13. Epithelial tumours
Benign epithelial tumours increase with age and are most
common in peri-menopausal women.
The most common epithelial tumours are serous
cystadenomas, accounting for 20–30 per cent of benign
tumours in women under 40.
Typically, serous cystadenomas are unilocular and rarely
involve the opposite ovary. It has papilliferous growths on the
inner surface (may also be on the outer surface making
distinction from a malignant tumour very difficult). The fluid
content is thin and serous, epithelial lining is cuboidal or
columnar epithelium and they occasionally contain calcified
granules known as psammoma bodies.

14. Serous cystadenoma

15. Mucinous cystadenomas are large multiloculated,
unilateral cysts (bilateral in 10 per cent of cases.),
full of thick mucin, and may reach great size. Rarely
they rupture, releasing mucin-producing cells which
may implant and continue to secrete mucin which
compromises bowel function and gives rise to
significant mortality (pseudomyxoma peritonei).
Brenner tumours are often small tumours found
incidentally within the ovary. They may secrete
oestrogen, so they can present with abnormal
vaginal bleeding.

16. Sex cord stromal tumours
Ovarian fibromas are the most common sex cord stromal
tumours. They are solid ovarian tumours composed of stromal
cells. They present in older women often with torsion due to
the heavinesss of the ovary.
Occasionally, patients may present with Meig syndrome
(pleural effusion, ascites and ovarian fibroma). Following
removal of the ovarian fibroma, the pleural effusion will often
resolve.
Thecomas are benign oestrogen-secreting tumours. They
often present post-menopause with manifestations of excess
oestrogen production such as post-menopausal bleeding.
Although benign, they may induce an endometrial carcinoma.

17. Other ovarian cysts
Other cysts occasionally presenting as ovarian
tumours include fimbrial cysts, paratubal cysts
and other uncommon embryologically derived
cysts such as cysts of Morgani.

18. Features of malignant versus benign
ovarian neoplasms
• Age: in childhood and in older women, there is
an increased risk of malignancy.
• Pain: pain can occur in both. Acute pain usually
indicates torsion or haemorrhage.
• Rapid growth: suspect malignancy.
• Bilaterality: 75% of malignant disease and 15%
of benign lesions are bilateral.
• Consistency: solid, nodular and/or irregular
features are suggestive of malignancy.

19. • Fixation of the mass: suspect malignancy.
• Ascites: ascites is associated with malignancy.
• Leg/vulval oedema, venous
obstruction/thrombosis: this is strongly
suggestive of malignancy.
• Evidence of distant metastasis: indicates
malignancy.