Lumps in the groin

Lumps in the groin:

Differential diagnosis

Inguinal hernia, femoral hernia, enlarged lymph nodes, saphena varix, hydrocele of the cord (or of the canal of Neck in women), vaginal hydrocele, undescended testis, lipoma of the cord, femoral aneurysm, psoas abscess.

Determining the diagnosis

Hernia

A hernia (usually) has a cough impulse (i.e. it expands on coughing) and (usually) reduces with direct pressure or on lying down unless, uncommonly, it is incarcerated (i.e. the contents of the hernia are fixed in the hernia sac by their size and by adhesions). 

Movement of the lump is not the same as expansion. Many groin lumps have a transmitted impulse on coughing (i.e. they move) but do not expand on coughing. 

Since inguinal and femoral hernias arise from within the abdomen and descend into the groin, it is not possible to get above them. For lumps that arise from within the scrotum, the superior edge can be palpated (i.e. it is possible to get above them).

Once a hernia has protruded through the abdominal wall, it can expand in any direction in the subcutaneous tissues and therefore the position of the unreduced hernia cannot be used to establish whether it is inguinal or femoral. The point of reduction of the hernia establishes whether it is an inguinal or femoral hernia.

• Inguinal: the hernia reduces through the abdominal wall at a point above and medial to the pubic tubercle. An indirect inguinal hernia often descends into the scrotum; a direct inguinal hernia rarely does.
• Femoral: the hernia reduces through the abdominal wall at a point below and lateral to the pubic tubercle.

Enlarged inguinal lymph nodes: A firm, non-compressible, nodular lump in the groin. Look for pathology in the skin of the scrotum and penis, the perianal area and anus, and the skin and superficial tissues of the thigh and leg.

Saphena varix A dilatation of the proximal end of the saphenous vein. Can be confused with an inguinal or femoral hernia because it has an expansile cough impulse (i.e. expands on coughing) and disappears on lying down. It is easily compressible and has a fluid thrill when the distal saphenous vein is percussed.

Hydrocele of the cord (or of the canal of Nack in women)

A hydrocele is an abnormal quantity of peritoneal fluid between the parietal and visceral layers of the tunica vaginalis, the double layer of peritoneum surrounding the testis and which was the processus vaginalis in the fetus. Normally, the processus vaginalis becomes obliterated along its entire length, apart from where it surrounds the testis where a potential space remains between the parietal and visceral layers. If the central
part of the processus vaginalis remains patent, fluid secreted by the trapped peritoneum accumulates and forms a hydrocele of the cord (the equivalent in females is known as the canal of Nack). A hydrocele of the cord may therefore be present in the groin.

Undescended testis

May be on the correct anatomical path, but may have failed to reach the scrotum (incompletely descended testis), or may have descended away from the normal anatomical path (ectopic testis). The lump is smooth, oval, tender to palpation, non-compressible, and there is no testis in the scrotum.

Lipoma of the cord

A non-compressible lump in the groin, with no cough impulse.

Femoral aneurysm

Usually in the common femoral artery (rather than superficial or profunda femoris branches) and therefore located just below the inguinal ligament. Easily confused with a femoral hernia. Like all aneurysms they are expansile (but unlike hernias they do not expand on coughing).

Psoas abscess

The scenario is one of a patient who is unwell with a fever, with a soft, fluctuant, compressible mass in the femoral triangle.