Groin Mass (Inguinal Mass): Causes and When to Worry

What counts as a groin mass

The groin (inguinal region) contains several structures that can form lumps: the inguinal canal where hernias come through, chains of lymph nodes that drain the legs, genitals, buttocks and lower belly wall, the femoral artery and vein, the spermatic cord in men, and skin with hair follicles and sweat glands. The type of lump usually depends on which of these it comes from.

Common causes of a lump in the groin

Inguinal hernia

The most common groin mass in adults, and far more common in men. Part of the bowel or fatty tissue pushes through a weak spot in the lower belly wall. Clues:

• a soft bulge above the groin crease that gets bigger when you stand, cough or strain
• it shrinks or disappears when you lie down or push it gently
• a dragging or aching feeling, worse at the end of the day
• in men, it may extend down into the scrotum

See inguinal hernia. A femoral hernia appears just below the groin crease, on the upper inner thigh. It is more common in women and more likely to get stuck, so it is usually repaired promptly. See femoral hernia.

Swollen lymph nodes

Groin lymph nodes swell when they fight infection in the area they drain. Normal groin nodes can be felt in many healthy adults and can be up to about 1.5 cm. Reactive nodes are usually:

• soft or rubbery, mobile and often tender
• linked to an obvious cause: an infected cut, ingrown toenail, athlete's foot, insect bite, cellulitis, or a sexually transmitted infection such as herpes, syphilis or chlamydia
• shrinking within 2 to 6 weeks

See swollen lymph nodes and lymphadenopathy.

Skin and soft tissue lumps

• Lipoma: a soft, doughy, painless fatty lump that moves under the skin and grows slowly. See lipoma.
• Epidermoid or sebaceous cyst: a round lump in the skin, sometimes with a central dot, which can become inflamed.
• Abscess or boil: a red, hot, painful, fluctuant lump that may burst and drain pus. Shaving and friction increase the risk.
• Hidradenitis suppurativa: recurrent painful lumps and tunnels in the groin and armpits.

Lumps from the testicle or spermatic cord

In men, a hydrocele, varicocele or spermatocele can extend upward and feel like a groin mass. An undescended testicle can sit in the groin in boys and is found at newborn and childhood checks.

Less common but serious causes

How to tell groin lumps apart

How doctors diagnose a groin mass

A clinician will ask how long the lump has been there, whether it changes size with standing or straining, whether it hurts, and about recent infections, sexual history, weight loss, night sweats and any procedures through the groin. They examine you both standing and lying down, ask you to cough, and check the skin of the legs, feet, genitals and anus for an infection or tumor that could explain swollen nodes.

Tests may include:

• Ultrasound: the first-line test. It distinguishes a hernia, a node, a cyst, an abscess or an aneurysm.
• Blood tests for infection or blood cancers, and STI tests if relevant.
• CT or MRI for deep or complex masses.
• Needle or excision biopsy of a node that is hard, fixed, larger than about 2 cm or persisting beyond 4 to 6 weeks without explanation.

Treatment

• Hernia: surgical repair, open or keyhole (laparoscopic), with mesh. Small, painless inguinal hernias in men can sometimes be watched. Femoral hernias are usually repaired because they strangulate more often.
• Reactive lymph nodes: treat the underlying infection; the node then shrinks.
• Abscess: incision and drainage, sometimes with antibiotics.
• Lipoma or cyst: removal if it is painful, growing or bothersome.
• Cancer: treatment of the primary cancer, which may include surgery, radiotherapy or chemotherapy.

Frequently asked questions

What is an inguinal mass?

An inguinal mass is a lump in the groin, the crease between the lower abdomen and thigh. The word "inguinal" means relating to the groin. The most common inguinal masses are hernias and swollen lymph nodes, followed by lipomas, cysts and abscesses.

Is a lump in the groin a hernia or a lymph node?

A hernia usually bulges when you stand, cough or strain and goes back in when you lie down. A lymph node is a fixed, bean-shaped lump that does not change with coughing, often tender, and may follow an infection on the leg or genitals. An ultrasound can confirm which it is.

When should I worry about a groin lump?

Get emergency care for a painful, hard bulge that will not go back in, especially with vomiting. See a doctor for a lump that is hard, fixed, growing, larger than about 2 cm, or lasts more than 2 to 3 weeks, or that comes with fever, night sweats or weight loss.

Can a groin lump be cancer?

Occasionally. Lymphoma, or cancer that has spread from the skin of the leg, anus, vulva or penis, can cause hard, painless, enlarged nodes. Most groin lumps are hernias, reactive nodes or benign lumps, but a persistent, hard or growing lump should be examined and may need a biopsy.

Do swollen groin lymph nodes go away on their own?

Usually. Nodes that swell in response to an infection typically shrink within 2 to 6 weeks once the infection clears. If a node keeps growing, becomes hard or fixed, or is still enlarged after about a month, have it checked.