The differential diagnosis of a groin lump covers a wide range of pathologies. It is possible to distinguish between most of these causes with a thorough history and examination. Some of the common causes are listed below:
- Hernia - inguinal or femoral
- Femoral artery aneurysm
- Psoas abscess
- Undescended testis
Like any history, start with open questions to gather all the background information you need, before focussing your questions on specific conditions. Follow the usual format:
- presenting complaint
- history of presenting complaint
- past medical and surgical history (previous surgery in the groin can lead to incisional hernias)
- drug history
- family history
- social history (heavy labour can result in hernias)
When asking about pain the SOCRATES acronym is a very useful tool.
History of Presenting Complaint
- When did it first appear?
- Is it present all the time?
- Are you able to push it back in?
- Are there any other symptoms? (pain, difficulty urinating, haematuria, fever)
- Have they had a previous lump?
Past Medical and Surgical History
- Any previous surgery? (especially relevant if there is an incision in the groin)
- Any recent trauma/infection of the lower limb? (can cause lymphandenopathy)
Examining the groin lump should be done in two positions: once with the patient lying down and once standing up.
The different causes of groin lumps have their own characteristics owing to the anatomy. Therefore a sound understanding of the underlying structures makes the examination much easier.
- Inguinal hernia - can be direct or indirect. Indirect inguinal hernias enter the inguinal canal and protrude out of the external inguinal ring. In contrast, a direct hernia protrudes through a weakness in the canal wall rather than traveling through it. Both types have cough impulse. They should be painless and reducible. Painful hernias may indicate incarceration. The lump should become more prominent on standing. Ask the patient to reduce their hernia, as they are less likely to cause themselves any pain.
- Femoral hernia - It appears inferior and lateral to the pubic tubercle as the bowel passes into the femoral canal. They are more commonly seen in females.
- Lymphandenopathy - the lymph nodes are found below the inguinal ligament. They feel firm, but non-tender and do not usually affect the overlying skin.
- Femoral artery aneurysm - the key feature is recognising whether the mass is expansile. A pulsatile mass can either be an artery or a femoral hernia.
- Psoas abscess - may be painful and can exhibit lymphadenopathy. The patient is likely to have signs of systemic illness such as tachycardia, tachypnoea and fever.
- Undescended testis - the scrotum on the ipsilateral side will be empty. However, a retracted testis can be manipulated back into the scrotum. It is important to differentate between the two. Scrotal examination should always follow an examination of a groin lump.
An abdominal and PR examination should also be performed to exclude any other masses which may contribute to a hernia and/or lymphandenopathy.
Imaging is generally not required as it is possible to clinically differentiate between the causes of a groin lump. Ultrasound may be useful to distinguish between solid and fluid lumps.