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Adnexal masses, O-RADS scoring, tumour markers - and when surgery is warranted.

Most ovarian and tubal masses are benign. A structured pathway - TVUS, IOTA and O-RADS, CA-125 and MRI where needed - separates what to watch from what to remove.

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A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Editorial team

    Written by our editorial team from the UK sources listed on each page.

  • 02

    Sourced from guidance

    Checked against NICE, RCOG, BGCS and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including IOTA simple rules, O-RADS risk stratification and BRCA-informed care.

Key facts

Adnexal masses at a glance.

The essentials, in plain English - the four common patterns, how risk is measured, and who needs a gynae-oncology opinion.

  • What it is

    A mass of the ovary or fallopian tube - most are benign, but a minority are borderline or malignant and need specialist input.

  • Functional cysts

    Follicular and corpus luteum cysts are the commonest finding - usually resolve within one to three menstrual cycles.

  • Benign tumours

    Dermoid teratoma, endometrioma and serous or mucinous cystadenoma are the classic benign patterns.

  • Malignant risk

    High-grade serous carcinoma is the commonest ovarian cancer - fallopian tube fimbriae are the likely origin.

  • Risk stratification

    TVUS with IOTA simple rules and O-RADS scoring guides who needs specialist referral and who can be observed.

  • Family history

    BRCA1, BRCA2 and Lynch syndrome carry a lifetime ovarian cancer risk - a family-history review is part of every workup.

Why this guide matters

Structured triage, not guesswork.

Ovarian cancer has a poor reputation because it presents late. Structured ultrasound reporting and a clear escalation ladder change that. The three points below shape the rest of the page.

  • Ultrasound is the starting point

    Transvaginal ultrasound with IOTA simple rules and O-RADS scoring stratifies almost every adnexal mass at the first visit.

  • Tumour markers add signal

    CA-125 combined with menopausal status gives the Risk of Malignancy Index; germ cell and sex cord markers matter in younger patients.

  • BRCA changes the conversation

    A strong family history opens the door to genetics, enhanced surveillance and risk-reducing salpingo-oophorectomy after childbearing.

How the diagnosis is made

From first scan to a clear plan.

The steps a UK GP, gynaecologist or radiologist will normally follow, in order - so you know what to expect and why.

  1. 01

    Assessing

    History and pelvic exam

    Cycle history, pain, bloating, urinary symptoms, family history of breast or ovarian cancer and a bimanual pelvic examination.

  2. 02

    Assessing

    Transvaginal ultrasound

    The first-line imaging - describes size, laterality, unilocular versus multilocular, solid components, papillary projections and vascularity.

  3. 03

    Assessing

    IOTA simple rules and O-RADS

    Structured reporting classifies a mass as benign (B-rules), malignant (M-rules) or inconclusive - and assigns an O-RADS risk score 1 to 5.

  4. 04

    Confirming

    CA-125 with RMI or ROMA

    CA-125 combined with menopausal status and ultrasound score gives a Risk of Malignancy Index; ROMA adds HE4 for post-menopausal triage.

  5. 05

    Confirming

    Targeted tumour markers

    AFP, beta-hCG, LDH and inhibin B when a germ cell or sex cord stromal tumour is suspected - especially in younger patients.

  6. 06

    Confirming

    MRI pelvis when indeterminate

    Multiparametric MRI with O-RADS MRI scoring clarifies indeterminate lesions and avoids unnecessary surgery.

  7. 07

    Planning

    Staging CT and MDT referral

    If malignancy is suspected, CT chest, abdomen and pelvis stages disease and a gynae-oncology MDT plans surgery and systemic therapy.

Typical timeline: first scan to a settled plan in a small number of weeks.

Symptoms

What an adnexal mass can feel like.

Many adnexal masses are silent. The features below are the ones that most often prompt a scan - and the ones to escalate quickly.

  • Pelvic pain or pressure

    A dull ache, dragging sensation or unilateral lower abdominal discomfort - often the first symptom of a persistent cyst.

  • Bloating and early satiety

    Persistent abdominal distension or feeling full quickly - one of the classic warning symptoms for ovarian cancer.

  • Menstrual disturbance

    Heavier, longer or irregular periods can accompany functional cysts, endometriomas and some hormonally active tumours.

  • Acute severe pain

    Sudden, one-sided pain may signal torsion, rupture or haemorrhage - a same-day gynaecology assessment is needed.

  • Urinary and bowel changes

    Frequency, urgency, constipation or a sense of incomplete emptying from local mass effect on the bladder or rectum.

  • Post-menopausal mass

    Any new adnexal mass after menopause deserves prompt imaging and CA-125 - the pre-test probability of malignancy is higher.

  • Incidental finding

    Many masses are discovered on scans done for unrelated reasons - most are benign but still need structured reporting.

  • Red flag - ascites or weight loss

    New ascites, unexplained weight loss, or a fixed pelvic mass warrants urgent two-week-wait referral for suspected gynaecological cancer.

Treatment

How adnexal masses are managed in the UK.

A stepped pathway: observe simple low-risk cysts, remove benign symptomatic masses laparoscopically, and refer suspicious lesions to a gynae-oncology MDT for staging surgery.

  • Watchful waiting

    Simple, unilocular cysts under 5 cm in pre-menopausal patients are usually observed with a repeat scan in six to twelve weeks.

  • Repeat imaging

    Persistent but low-risk masses are followed with interval TVUS and CA-125 - many benign lesions remain stable for years.

  • Hormonal suppression

    For recurrent functional cysts, a combined oral contraceptive can prevent new ovulation-driven cysts, though it will not shrink an existing one.

  • Laparoscopic cystectomy

    Keyhole removal of the cyst with ovarian preservation - the standard for benign, symptomatic or enlarging masses in younger patients.

  • Laparoscopic oophorectomy

    Removal of the whole ovary and tube - used when the ovary cannot be safely preserved or after menopause.

  • Open surgical staging

    Suspected malignancy is managed by gynae-oncology with midline laparotomy, washings, biopsies, hysterectomy and node sampling as indicated.

  • Chemotherapy

    Platinum and taxane-based regimens for epithelial ovarian cancer - neoadjuvant, adjuvant or for recurrence, guided by stage and molecular profile.

  • Risk-reducing salpingo-oophorectomy

    For BRCA1, BRCA2 and Lynch carriers - removal of both tubes and ovaries once childbearing is complete substantially reduces lifetime risk.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or gynaecologist knows your history and imaging and can tell you which parts apply to you. If in doubt, get seen.

  • RCOG Green-top Guideline 62. Management of suspected ovarian masses in premenopausal women.

  • RCOG Green-top Guideline 34. Ovarian cysts in postmenopausal women.

  • NICE NG12 and DG31. Suspected cancer recognition and referral; ovarian cancer risk assessment.

  • ACR O-RADS Ultrasound and MRI risk stratification systems for adnexal lesions.

  • IOTA Group. Simple rules and ADNEX model for the classification of adnexal masses.

  • BGCS. Guidelines for the management of epithelial ovarian cancer.

Red flags

When an adnexal mass needs urgent attention.

Most masses are followed safely in the community. The situations below are the ones that aren’t - and where a specialist opinion is needed quickly.

  • Suspected torsion

    Sudden severe unilateral pain with nausea and vomiting - an emergency needing same-day imaging and laparoscopy to save the ovary.

  • Cyst rupture with haemodynamic change

    Sudden pain, dizziness or collapse suggests bleeding into the peritoneum - attend the emergency department immediately.

  • Post-menopausal adnexal mass

    Any new mass after menopause warrants prompt CA-125, TVUS and gynaecology referral - the malignancy risk is higher.

  • Persistent bloating or early satiety

    Symptoms most days for more than three weeks, especially over age 50 - trigger CA-125 and pelvic ultrasound under NICE NG12.

  • Ascites or a fixed pelvic mass

    New abdominal swelling with fluid, or a mass fixed to surrounding structures - urgent two-week-wait referral for suspected cancer.

  • Rapidly enlarging mass

    Fast growth on interval scans is a strong indicator for surgical staging rather than continued observation.

  • BRCA or Lynch family history

    A strong family history of breast, ovarian, endometrial or bowel cancer needs genetics referral and a risk-reducing plan.

  • Virilising features

    New hirsutism, voice change or clitoromegaly can signal a sex cord stromal tumour - warrants urgent gynaecology input.

  • Elevated germ cell markers in a young patient

    Raised AFP, beta-hCG or LDH in a woman under 40 with a solid ovarian mass points to a germ cell tumour needing tertiary care.

Living with it

A common finding, with a clear pathway.

Four things that make the biggest difference between a diagnosis and a plan - reassurance where it fits, follow-up where it matters, symptom awareness and family history.

A quiet reminder

A named mass is not a diagnosis of cancer.

The great majority of adnexal masses are benign. Structured reporting exists precisely to separate the reassuring from the concerning.

  1. 01 Reassurance

    Most masses are benign

    The great majority of adnexal masses - especially in pre-menopausal patients - are functional or benign and never need surgery.

  2. 02 Follow-up

    Turn up for interval scans

    If your clinician recommends observation, the interval scan is the point at which stability, growth or resolution is confirmed.

  3. 03 Symptoms

    Track what you feel

    A short symptom diary - bloating, pain, appetite, urinary changes - helps your team spot patterns that need action.

  4. 04 Family

    Know your family history

    A first-degree relative with ovarian, breast, bowel or endometrial cancer should prompt a genetics conversation.

Frequently asked

Everything we get asked about adnexal masses.

Quick answers on IOTA, O-RADS, CA-125, tumour markers, surgery and genetic risk.

  • What is an adnexal mass?

    An adnexal mass is a lump involving the ovary or fallopian tube, or occasionally the surrounding ligaments. It can be a simple fluid-filled cyst, a benign tumour such as a dermoid or endometrioma, a borderline tumour, or an ovarian or tubal cancer. Ultrasound and structured reporting classify the mass and guide next steps.

  • What are IOTA simple rules and O-RADS?

    IOTA simple rules are a set of five ultrasound features that suggest a mass is benign (B-rules) and five that suggest it is malignant (M-rules). O-RADS is a wider risk-stratification system that assigns a score from 1 (normal) to 5 (high risk of malignancy) and maps each score to a recommended management pathway - from no follow-up through to gynae-oncology referral.

  • Do I need surgery for an ovarian cyst?

    Not usually. Simple, unilocular cysts under 5 cm in pre-menopausal patients are typically observed and resolve on their own. Surgery is considered when the mass is symptomatic, enlarging, complex on imaging, persistent after several cycles, or when the O-RADS score, CA-125 and Risk of Malignancy Index suggest a higher chance of malignancy.

  • What does a raised CA-125 mean?

    CA-125 is a protein that can be raised in ovarian cancer, but also in endometriosis, fibroids, pelvic inflammatory disease, pregnancy and menstruation. It is interpreted alongside menopausal status and ultrasound findings using the Risk of Malignancy Index or the ROMA score. A single elevated value is not a diagnosis.

  • Which tumour markers are checked in younger patients?

    In women under about 40 with a solid or complex ovarian mass, AFP, beta-hCG, LDH and inhibin B are added to CA-125. These help identify germ cell tumours (dysgerminoma, yolk sac, choriocarcinoma) and sex cord stromal tumours (granulosa cell), which are far more common in this age group than epithelial cancer.

  • Should I have genetic testing?

    A significant personal or family history of ovarian, breast, endometrial or bowel cancer should prompt referral to clinical genetics. BRCA1, BRCA2 and Lynch syndrome all raise lifetime ovarian and tubal cancer risk. Carriers are offered surveillance, chemoprevention discussions and, once childbearing is complete, risk-reducing salpingo-oophorectomy.

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