Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Fibroids, polyps and adenomyosis
Obstetrics and gynaecology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending
!
Escalate haemorrhage, torsion-like pain or sepsis
Shock from uterine bleeding, severe acute pain with a mass, fever after instrumentation, urinary obstruction or rapidly enlarging postmenopausal mass requires urgent gynaecological assessment rather than routine fibroid or adenomyosis follow-up.
Action: Stabilise, exclude pregnancy, obtain urgent bloods and imaging appropriate to physiology, involve senior gynaecology and pursue haemostasis, infection control or surgery according to the acute mechanism.
Overview
Distinguish fibroids, endometrial polyps and adenomyosis by compartment and symptom pattern, select ultrasound or hysteroscopy, and match medical, hysteroscopic, radiological or surgical treatment to anatomy and fertility priorities.
These three structural causes occupy different compartments. A fibroid is a monoclonal benign smooth-muscle and connective-tissue tumour within or projecting from myometrium. A polyp arises from focal endometrial glands and stroma inside the cavity. Adenomyosis consists of endometrial-type glands and stroma within myometrium with surrounding muscular change. Compartment explains test choice: ultrasound maps myometrium and adnexa, while hysteroscopy directly sees the cavity.
Fibroid symptoms depend on site, number and size. Submucosal fibroids project into the cavity and can cause disproportionate heavy or prolonged bleeding and infertility even when small. Intramural fibroids can increase bleeding and uterine bulk. Subserosal or pedunculated lesions more often cause pressure, urinary frequency, constipation, abdominal enlargement or pain. Many fibroids are incidental and should not be treated merely because imaging found them; compare lesion anatomy with the patient’s actual symptoms.
Aetiology
01
Hormone-responsive myometrium
Fibroid clones grow within myometrium under genetic, extracellular-matrix, oestrogen and progesterone influences, with prevalence and symptoms varying widely.
02
Focal endometrial overgrowth
Polyps arise from local endometrial gland and stromal proliferation around a vascular core, sometimes associated with oestrogen or tamoxifen exposure.
03
Myometrial adenomyotic change
Endometrial-type glands and stroma become embedded within myometrium, provoking local smooth-muscle hypertrophy and inflammatory pain mechanisms.
Pathophysiology
1
Cavity distortion
Submucosal fibroids and polyps expand the bleeding surface and create abnormal fragile vessels that disrupt coordinated endometrial shedding.
2
Myometrial dysfunction
Intramural fibroids and adenomyosis impair effective compression of endometrial vessels and alter prostaglandin signalling, increasing bleeding and cramping.
3
Bulk compression
Growing myometrial or subserosal fibroids press on bladder, bowel, ureters and pelvic structures, producing pressure independent of menstrual loss.
4
Inflammatory pain
Adenomyotic tissue responds cyclically within muscle, producing local inflammation, neural sensitisation and uterine tenderness during and between periods.
Clinical features and red flags
Submucosal fibroid
A lesion bulging into the endometrial cavity is strongly linked to heavy bleeding and may be accessible to hysteroscopic resection.
Bulk fibroid symptoms
Abdominal enlargement, pressure, urinary frequency, constipation or an irregular firm enlarged uterus suggests intramural or subserosal fibroid burden.
Endometrial polyp
Recurrent intermenstrual or postcoital spotting with a focal cavity lesion supports a polyp, whose histology is established after directed removal.
Adenomyosis
Heavy painful periods with a diffusely bulky tender uterus and myometrial ultrasound features distinguish adenomyosis from a discrete leiomyoma.
Incidental fibroid
A small non-distorting lesion without matching symptoms may require no treatment, preventing imaging prevalence from becoming a surgical indication.
Atypical postmenopausal massRed flag
New growth, bleeding, pain or suspicious imaging after menopause requires urgent specialist assessment because a presumed fibroid diagnosis is not sufficient.
Red flags requiring action
Postmenopausal bleeding or a newly enlarging postmenopausal uterine or endometrial lesion requires urgent malignancy assessment rather than presumptive benign disease.
Persistent intermenstrual bleeding, tamoxifen use, an irregular focal cavity lesion or endometrial risk may require hysteroscopy and histology even when a polyp seems likely.
Investigations
01Pregnancy test and full blood countFirst step
Why
Exclude pregnancy-related bleeding and measure anaemia while structural assessment proceeds.
Interpretation and limitations
Positive hCG redirects care; blood count measures consequence but does not distinguish fibroid, polyp or adenomyosis.
02Transvaginal pelvic ultrasound
Why
Map fibroids and myometrium, assess adenomyosis features and evaluate ovaries and adnexa.
Interpretation and limitations
Report location and cavity distortion. Ultrasound supports but does not histologically diagnose a polyp or exclude all sarcoma and superficial endometriosis.
03Outpatient hysteroscopy
Why
Directly identify a polyp or submucosal fibroid and enable biopsy or treatment.
Interpretation and limitations
Complete cavity visualisation defines lesion attachment and resectability. Histology from removed tissue determines polyp and endometrial pathology.
04Endometrial sampling
Why
Assess hyperplasia or malignancy when bleeding pattern and risk justify tissue diagnosis.
Interpretation and limitations
Sample in the hysteroscopy context for risk-bearing HMB under NICE. An inadequate or discordant specimen requires further assessment.
05MRI pelvis
Why
Differential diagnosis
01
Endometriosis
Cyclical pain and dyspareunia overlap with adenomyosis, and both can coexist; extrauterine disease may remain despite normal uterine imaging.
02
Endometrial hyperplasia or cancer
Irregular bleeding and a cavity lesion require histology because ultrasound cannot reliably distinguish every polyp from proliferative or malignant tissue.
03
Ovarian or adnexal mass
Pelvic fullness and pain may arise outside the uterus; complete ultrasound assessment prevents an enlarged adnexa being labelled fibroid disease.
04
Pregnancy-related uterine change
Pregnancy, miscarriage and retained tissue can enlarge the uterus and alter the cavity, making pregnancy testing essential before classification.
Management
01Cavity lesionInspect and treat polyps or submucosal fibroidsFirst stepIntermenstrual bleeding, imaging or HMB suggests a focal endometrial-cavity lesion.+
1Offer outpatient hysteroscopy, explain analgesia and anaesthetic alternatives and obtain consent for biopsy or see-and-treat removal if appropriate.
2Remove a symptomatic polyp or suitable submucosal fibroid hysteroscopically and send all tissue for histological examination.
3Review bleeding and histology and plan staged resection or another technique when size, depth or pain prevents complete treatment.
02Small non-distorting fibroid or adenomyosisBegin with mechanism-matched medical treatmentFibroids are under 3 cm without cavity distortion, or adenomyosis is suspected or diagnosed.+
1PreferredDiscuss the LNG-IUS as preferred NICE treatment when acceptable, incorporating contraception, fertility plans and the expected first-cycle bleeding pattern.
Complications
01
Anaemia and haemorrhage
Cavity lesions and adenomyosis can cause chronic iron loss or acute flooding, with fatigue, cardiovascular strain and occasional need for emergency control.
02
Reproductive effects
Cavity-distorting fibroids and some polyps can impair implantation or pregnancy, while treatment can affect adhesions, uterine integrity and placentation.
03
Pressure organ dysfunction
Large fibroids may cause urinary retention, hydronephrosis, constipation, venous compression, progressive abdominal distension and reduced mobility.
04
Recurrence or persistence
Fibroids and polyps can recur after uterus-preserving treatment, and residual adenomyosis may continue pain or bleeding after focal intervention.
05
Procedure-related harm
Hysteroscopic perforation, surgical bleeding, adhesions, embolisation complications and hysterectomy morbidity require detailed anatomy-specific consent and follow-up.
Monitoring and follow-up
Follow bleeding, pain, pressure, bladder and bowel symptoms, haemoglobin and patient-defined function after each medical or procedural intervention.
Record fibroid measurements, location and cavity distortion using comparable imaging so true change can be separated from technique variation.
Track every removed polyp or fibroid specimen to histology and reconcile unexpected atypia or malignancy with the urgent specialist pathway.
After myomectomy or embolisation, document recurrence surveillance, contraception or conception advice and which pregnancy team should review future care.
Reassess new postmenopausal bleeding, rapid symptom change, acute pain, fever, urinary obstruction or severe anaemia urgently rather than waiting for routine follow-up.
Special situations
Compartment predicts bleeding
A small cavity lesion can produce major bleeding, while a large outer-wall fibroid may mainly cause pressure; size alone does not rank causality.
Histology belongs to polyps
A benign ultrasound impression cannot establish cellular diagnosis, so removed focal endometrial tissue should be examined pathologically.
Adenomyosis is a working diagnosis
Characteristic symptoms and transvaginal imaging support treatment without requiring hysterectomy solely to obtain proof.
Uterus-preserving is not fertility-neutral
Myomectomy and embolisation retain the uterus but can affect adhesions, uterine integrity, placentation and pregnancy outcome in different ways.
Ovaries are a separate consent
Hysterectomy for fibroid or adenomyosis does not automatically require ovary removal; benefits and surgical menopause risks need their own decision.
Common pitfalls
01
Treating every ultrasound fibroid as the cause of symptoms without checking site, cavity distortion and competing disease.
02
Using ordinary pelvic ultrasound as a complete substitute for hysteroscopy when a polyp is suspected.
03
Fitting an LNG-IUS without assessing substantial cavity distortion or obtaining a consented pelvic examination.
04
Promising that myomectomy prevents recurrence or that uterine artery embolisation has no fertility implications.
05
Calling a growing postmenopausal mass benign without specialist review of symptoms and imaging.
06
Removing ovaries automatically during hysterectomy for benign uterine disease without separate informed consent.
Practice
Two practice questions
Your practice draft is saved in this browser.
Question 1 of 2
0 correct
Obstetrics and gynaecologyOriginal SBA
Submucosal fibroid treatment
A patient with heavy menstrual bleeding has a 2 cm fibroid projecting substantially into the uterine cavity. She wants uterine preservation and medical treatment has failed. Which targeted procedure should be discussed?
Sources and review status5 sources · checked 27 Aug 2026 · clinical review pending+
Sources
Sources and review status
National guidance is shown before implementation-dependent detail. Apply principles in context and verify current guidance when a decision affects care. Source check completed 27 Aug 2026; clinical approval remains outstanding.
Polyps commonly cause intermenstrual spotting, postcoital bleeding, irregular loss or HMB. Ultrasound may show a focal echogenic lesion, but ordinary transvaginal scanning can miss a small polyp. Outpatient hysteroscopy confirms the cavity lesion and permits targeted removal. Histology is important because a minority contain hyperplasia or malignancy, with risk rising after menopause and with abnormal bleeding or tamoxifen. Blind curettage may miss a focal polyp.
Adenomyosis often presents with progressively painful heavy periods, chronic pelvic pain, dyspareunia and a uniformly bulky tender uterus, though symptoms and imaging vary. Transvaginal ultrasound is NICE’s preferred test when substantial dysmenorrhoea or a bulky tender uterus raises suspicion. Features include a globular uterus, asymmetrical myometrium, myometrial cysts, fan-shaped shadowing and an irregular junctional zone. MRI can help when ultrasound is inconclusive or detailed mapping will change specialist treatment, but it is not the first HMB investigation.
For fibroids, ultrasound reports should state size in three dimensions, number, uterine location, relationship to endometrium and serosa, cavity distortion and adnexal findings. Saline infusion or hysteroscopy can refine cavity involvement. Rapid growth alone does not reliably diagnose sarcoma, but a new or growing postmenopausal mass, atypical imaging, systemic features or postmenopausal bleeding requires specialist oncological consideration. No preoperative scan completely excludes sarcoma in a presumed fibroid.
Initial bleeding treatment can start while investigation proceeds. NICE prioritises the 52 mg levonorgestrel intrauterine system for HMB when there is no identified pathology, adenomyosis or fibroids below 3 cm that do not distort the cavity. Cavity distortion can prevent safe placement or reduce effectiveness. If declined or unsuitable, non-hormonal tranexamic acid or NSAIDs and hormonal combined contraception or cyclical progestogens are considered according to contraindications and fertility plans.
Submucosal fibroids and symptomatic polyps are approached hysteroscopically when feasible, with consent for fluid, bleeding, perforation and incomplete removal. Fibroids 3 cm or larger prompt specialist discussion because medicine effect may be limited. Myomectomy removes fibroids while preserving the uterus but carries bleeding, adhesion and recurrence risks. Uterine artery embolisation causes ischaemic shrinkage and can be effective for bleeding and bulk, but reproductive outcomes are less predictable than after selected myomectomy. Hysterectomy definitively removes uterine symptoms but ends uterine fertility.
Adenomyosis is treated according to bleeding, pain and reproductive goals. LNG-IUS, combined hormonal contraception, progestogens, tranexamic acid and NSAIDs can reduce symptoms. Uterine artery embolisation and other uterus-preserving interventions require specialist selection because evidence and fertility effects differ. Hysterectomy is definitive for uterine adenomyosis when symptoms remain severe and pregnancy is no longer desired; oophorectomy is a separate decision and is not required simply to treat adenomyosis.
Key points
Fibroids are benign myometrial smooth-muscle tumours; submucosal lesions distort the cavity and commonly drive bleeding, intramural lesions enlarge the wall and subserosal lesions more often cause pressure.
Endometrial polyps are focal cavity overgrowths that commonly cause intermenstrual, postcoital or irregular bleeding and require histology when removed.
Adenomyosis is endometrial-type tissue within myometrium, typically producing heavy painful periods, chronic pelvic pain and a diffusely bulky tender uterus.
Use transvaginal ultrasound to map fibroids and adenomyosis when acceptable; report fibroid size, number, site and cavity distortion rather than diameter alone.
Use outpatient hysteroscopy when a polyp or submucosal fibroid is suspected because direct cavity inspection permits targeted biopsy and see-and-treat removal.
NICE recommends an LNG-IUS as preferred treatment for HMB with no pathology, fibroids under 3 cm that do not distort the cavity, or suspected or diagnosed adenomyosis when acceptable.
NICE advises specialist referral for fibroids 3 cm or larger to discuss medicines, uterine artery embolisation, myomectomy and hysterectomy according to location, severity and reproductive goals.
Hysteroscopic removal is the directed treatment for submucosal fibroids and symptomatic cavity polyps; intramural or subserosal lesions require different approaches.
Severe anaemia, syncope or continuous flooding from a cavity-distorting lesion requires acute haemostasis and expedited definitive treatment.
Sudden severe pain, vomiting, fever or peritonism is atypical for stable adenomyosis or fibroid symptoms and raises degeneration, torsion, infection or adnexal disease.
Hydronephrosis, urinary retention, bowel obstruction or major venous compression from a large mass requires urgent organ-function and specialist review.
Clarify complex fibroid or adenomyosis anatomy when ultrasound is inconclusive or procedure planning requires additional mapping.
Interpretation and limitations
MRI is not a routine first-line HMB test and cannot guarantee benign histology; use it only when the result changes specialist decisions.
06Renal tract and pressure assessment
Why
Detect hydronephrosis, retention or organ compression from a large uterine mass.
Interpretation and limitations
Renal impairment or upper-tract dilatation increases urgency and may change imaging, surgical route and preoperative preparation.
2Use tranexamic acid, NSAIDs, combined hormonal contraception or cyclical progestogen when the device is unsuitable or declined and contraindications permit.
3Review after adequate use and refer for specialist procedural choices if bleeding, pain, anaemia or bulk remains unacceptable.
03Fibroid at least 3 cmUse specialist anatomy and fertility planningOne or more fibroids measure 3 cm or more or produce substantial pressure, fertility or bleeding symptoms.+
1Refer to specialist care and map number, size, cavity relationship, symptoms, anaemia and reproductive priorities before selecting treatment.
2Offer symptom control with tranexamic acid or NSAID while discussing LNG-IUS or hormonal treatment, GnRH options, embolisation, myomectomy and hysterectomy as suitable.
3Explain recurrence, ovarian and uterine fertility implications, pregnancy after surgery and the possibility that medical response is limited by size and distortion.
04Atypical or refractoryReassess diagnosis before definitive surgeryDefinitiveSymptoms persist despite treatment, imaging is discordant or postmenopausal features raise concern.+
1Review pregnancy, cervix, endometrium, histology and whether the imaged lesion actually explains bleeding and pain.
2Obtain expert imaging or cancer-pathway review for a new postmenopausal mass, suspicious morphology, postmenopausal bleeding or unexplained systemic features.
3DefinitiveChoose definitive uterine surgery only after alternatives, fertility, route, ovarian conservation and expected symptom benefit are discussed.
Myomectomy preserves the uterus but fibroids can recur and pregnancy risks depend on incision; uterine artery embolisation can affect fertility, while hysterectomy is definitive and ends uterine pregnancy.
Adenomyosis diagnosis does not require hysterectomy histology before treatment; medical suppression and symptom response are reasonable, with surgery considered for refractory completed-family disease.