Groin swelling - red flag symptoms

Signs and symptoms of potentially serious pathology in patients presenting with groin swelling, including identifying inguinal and femoral hernias and when to refer.

Lyphmadenopathy in the groin may be sign of malignancy (Photo: Dr P Marazzi/Science Photo Library)
Lyphmadenopathy in the groin may be sign of malignancy (Photo: Dr P Marazzi/Science Photo Library)

Red flag symptoms

  • Very painful swelling
  • Patient is systemically unwell
  • Irreducible and tender swelling
  • History of cancer
  • Previous surgery/intervention in groin
  • Pulsatile swelling
  • Groin node with coexistent new trunk, limb or pelvic symptoms
  • Irregular vaginal discharge or bleeding
  • New firm testicular lump

A swelling in the groin is common and most diagnoses can be made by taking a focused history from the patient and performing a good clinical examination.

A clear understanding of the anatomy helps, although bear in mind that the groin is not a precise anatomical area.

Consider the age of the patient (check the scrotum in a male child) and clarify how long the lesion has been there for.

Questions to ask

  • Is the swelling painful, uncomfortable or asymptomatic?
  • What made the patient consult about it now?
  • Does the lump ever disappear or appear more obvious in certain positions?
  • Has the patient had any significant past illnesses or surgical procedures, particularly in or around the groin or adjacent area?
  • Is the swelling tender, smooth, red or infected?
  • Are there any problems passing urine?
  • Is there any risk of a sexually transmitted infection?

Examination

It is unlikely that you will be able to properly assess a groin swelling remotely, so if you are arranging a face-to-face assessment, ensure you wear appropriate PPE.

As with any examination, look at the patient before examining the area of interest, to see if they are well, appear anaemic, or are showing any other signs of ill health.

Consider the need for a chaperone for the groin examination. A full abdominal examination including scrotal examination (in men) is usually appropriate. A vaginal examination may be needed if you suspect a lymph node and there are any red flag vaginal symptoms. Also consider a gastrointestinal examination for hepatosplenomegaly.

Comparing the affected side with the groin on the other side is good practice and clinically helpful.

If there are any concerns regarding systemic illness, perform a full clinical examination, checking for evidence of widespread lymphadenopathy, if appropriate.

Differential diagnoses

Inguinal hernia
Inguinal hernias are common, accounting for 7% of all surgical outpatient referrals.

They are more common in men, and the incidence increases with age. Patients often describe a ‘dragging’ sensation associated with a hernia. Typically hernias gradually increase in size over time, but occasionally there is a clear mechanism of injury, such as having lifted a heavy item and the hernia ‘rupturing’.

Some 80% of hernias are termed indirect. They occur as a result of a protrusion of viscera through the internal inguinal ring. Direct inguinal hernias protrude directly through a weakness in the posterior wall of the inguinal canal. Sliding hernias are very rare and occur when a portion of viscera slides behind the peritoneal sac into the inguinal canal with the wall of the organ forming part of the hernial sac.

The patient should be examined both lying down and standing, as sometimes hernias are only visible when the patient is upright. If the lump is not obvious, a cough impulse should be elicited.

Surgical repair is usually advisable, however in some incidences a more conservative approach is suitable and a truss may be beneficial. There is an approximately 1% recurrence rate following repair.

Incarcerated hernias occur when the hernia is no longer reducible and may lead to strangulation. This situation warrants an urgent same-day surgical referral.

Congenital inguinal hernias are typically indirect and should be referred for urgent surgical outpatient assessment.

Femoral hernia
Although less common than inguinal hernias, femoral hernias are an important cause of groin lumps.

They are most commonly found in older parous women, and are very rare in children.

Classically this type of hernia is felt as a lump in the groin, lateral and inferior to the pubic tubercle but a large hernia may bulge over the inguinal ligament and make differential diagnosis difficult.

They are much more prone to strangulation than their inguinal counterparts, with 22% strangulating at 3 months and 45% at 21 months. In view of this, all femoral hernias should be repaired electively and conservative management is not recommended.

Lymphadenopathy
Lymphadenopathy in the groin may be a sign of malignancy or infection (consider syphilis and HIV).

Lymphadenopathy can be inflammatory and the septic focus may be in the lower limb. If no focus is found and the nodes are hard and growing into a large mass, consider a malignancy (metastatic or lymphoma); urgent referral may be needed. See the Cancer Research UK decision support tools, and risk assessment tools for more information.

Vascular pathology
A pulsatile mass in the groin may indicate a femoral artery aneurysm or, more commonly, a false aneurysm. This finding usually warrants a same-day surgical referral.

A saphena varix occurs as a result of dilatation at the top of the long saphenous vein, secondary to valvular incompetence. Typically the varix is soft and readily compressed, and disappears on lying down. There may be a pulsatile cough impulse mimicking an inguinal hernia. However, you would expect to find a saphena varix in association with significant distal varicose veins, which may aid diagnosis.

Undescended testes
An undescended testis is not an uncommon finding, occurring in 1-6% of male babies. It is more common in premature babies and is very rarely seen bilaterally.

Approximately 70% of undescended testes are palpable and are usually located near the pubic tubercle, in the inguinal canal (80%), or less commonly in the abdomen.

The testis is often small and abnormal with a short spermatic cord. They are often seen in association with an inguinal hernia.

Most undescended testis will have migrated into the scrotum by 3 months of age, with less than 1% remaining undescended by 1 year of age.

Undescended testes can have an impact on future fertility and are associated with a three-fold increase in risk of testicular carcinoma. Most cases are therefore surgically managed, although the optimum age to operate appears to be debatable.

Psoas abscess
The psoas major is a long muscle extending from the lateral borders of T12 to the L5 vertebrae. It then proceeds downward across the brim of the lesser pelvis and diminishes gradually in size, passing beneath the inguinal ligament and in front of the capsule of the hip joint, and ending in a tendon.

The clinical presentation of iliopsoas abscess is very variable and non-specific. The classical clinical triad consisting of fever, back pain, and limp is present in only 30% of the patients with iliopsoas abscess.

Other symptoms include vague abdominal pain, hip or thigh pain, malaise, nausea, and weight loss. Patients may also present with a painless or tender swelling below the inguinal ligament. Raised inflammatory markers may be useful, however psoas abscesses are best diagnosed via CT scan.

Superficial pathologies
It is also worth considering superficial benign pathologies, such as sebaceous cyst, lipoma and folliculitis

Key learning points

  • A full abdominal examination including scrotal examination (in men) is usually appropriate.
  • Inguinal hernias are common, accounting for 7% of all surgical outpatient referrals.
  • All femoral hernias should be repaired electively and conservative management is not recommended.
  • A pulsatile mass in the groin may indicate a femoral artery aneurysm or more commonly a false aneurysm.
  • Approximately 70% of undescended testes are palpable.
  • The classical clinical triad consisting of fever, back pain, and limp is present in only 30% of the patients with iliopsoas abscess.
  • If you suspect an inflamed lymph node, consider pelvic malignancy, haematological malignancy and STIs, such as syphilis and HIV.

Dr Harry Brown is a GP in Leeds. This article was reviewed and updated in May 2021 by Dr Pipin Singh GP Northumberland

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This is an updated version of an article that was first published in November 2013.

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