Groin Swellings
Most causes of lumps in the groin are non-urgent. Many patients do not realise this, however – the development of a groin swelling often heralds an urgent appointment, either because the patient fears sinister pathology, or because the patient knows the diagnosis but erroneously perceives it as an emergency. GPs generally welcome the problem, as diagnosis and disposal are usually straightforward.
Differential diagnosis
Common Diagnoses
- Sebaceous Cyst
- Palpable Lymph Nodes (LNs): ‘Normal’ or Secondary to an Infection
- Inguinal Hernia
- Femoral Hernia
- Saphena Varix
Occasional Diagnoses
- Retractile Testicle
- Abscess (Local)
- Metastatic Tumour (Usually as Skin-Fixed Lymphadenopathy)
- Hydrocele of Spermatic Cord
- Low Appendix Mass, Pelvic/Inguinal Tumour
- Lipoma
Rare Diagnoses
- Abscess (Psoas)
- Lymphoma
- Femoral Artery Aneurysm
- Neurofibroma
- Undescended or Ectopic Testis
Ready reckoner
Key distinguishing features of the most common diagnoses
| Sebaceous Cyst | LNs | Inguinal Hernia | Femoral Hernia | Saphena Varix | |
|---|---|---|---|---|---|
| Reducible | No | No | Possible | Possible | Yes |
| Cough Impulse | No | No | Yes | Possible | Yes |
| Palpable Thrill on Valsalva Manoeuvre | No | No | No | No | Yes |
| Fixed to Skin | Yes | No | No | No | No |
| Originates Above and Medial to Pubic Tubercle | Possible | Possible | Yes | No | No |
Possible investigations
Likely: None
Possible: FBC, ESR/CRP, GUM screen.
Small Print: Pelvic ultrasound.
- FBC and ESR/CRP useful if diffuse lymphadenopathy found, especially if no evidence of local cause or other significantly enlarged nodes found. Hb may be reduced and ESR/ CRP elevated in malignancy; WCC and ESR/CRP elevated in abscess, infection and blood dyscrasias
- Urethral, vaginal or endocervical swabs indicated if any associated discharge and/or suspicion of STD.
- Pelvic ultrasound useful if pelvic mass suspected.
Top Tips
- A large saphena varix can look very much like a small hernia. Try the Valsalva test and look for evidence of varicose veins.
- If the cause is local lymphadenopathy, look for local infective causes and don’t forget to consider STDs
- Don’t be surprised to find no abnormality – normal groin nodes in a slim person, and a normally retractile testis can cause great anxiety in patients and parents.
- If the history suggests a hernia, but nothing is obvious on examination, get the patient to raise the intra-abdominal pressure with a vigorous cough or by raising the legs straight up while lying on the couch – and remember to examine the patient standing up, too.
Red Flags
- Femoral herniae (commoner in women) are at high risk of strangulation, so always refer
- Undescended testis in the adult carries a high risk of malignancy. If the testis is not descended by the age of six months, then operative intervention is indicated. Bilateral undescended testes need urgent referral
- If lymphadenopathy is the cause, look elsewhere for abnormal lymph nodes and investigate or refer if any are found. Hard, skin-fixed nodes suggest metastatic malignancy – refer urgently.
- An acutely painful and irreducible groin lump suggests a strangulated or incarcerated hernia. If in any doubt, refer for urgent surgical assessment.