The asymptomatic groin swelling

A 75-year-old patient is admitted. He has had a palpable swelling in the right groin for 3 months. He is referred by his general practitioner to rule out a femoral hernia.

Upon admission, a slender man in an age-appropriate general condition is observed. The abdomen appears normal. In the area of the right groin, a roughly 5 cm firm elastic swelling can be palpated medial to the vessels on the ventral side of the thigh. The soft tissues show no redness. Auscultation reveals no bowel sounds. The medial and lateral inguinal rings are unremarkable. No insufficiency can be felt during provocation maneuvers.

The range of motion of the hips is free, but there is pain on the right side beyond 80° of flexion. Peripheral foot pulses are palpable.

Ultrasound shows an approximately 5 cm large, septated cystic structure. The hernial orifices are intact. Doppler sonography shows no indication of an aneurysm.

The subsequent CT scan showed the following findings:

This reveals bilateral but right-dominant labrum cysts associated with pincer impingement and advanced coxarthrosis. The therapeutic procedure discussed with the patient was alloplastic hip joint replacement.

Discussion:

Labrum cysts of the hip are relatively common findings, often discovered incidentally during imaging studies such as MRI. They are synonymous with terms like ganglion, ganglion cyst, juxta-articular cyst, mucous dorsal cyst, mucoid cyst, myxomatosis nodularis cutanea, or "bump" on the hand. These refer to a cystic pseudotumor in the area of a joint capsule or tendon sheath. They arise as a result of nonspecific proliferation of mesenchymal cells, degeneration of collagenous connective tissue, or overproduction of hyaluronic acid by fibroblasts.

Synovial cysts are pseudo-cysts lined with synovial epithelium, with a thick wall of granulation tissue, histiocytes, and giant cells. They are usually filled with clear, serous, or xanthochromic fluid rich in mucopolysaccharides. In contrast, ganglion cysts are structures filled with mucin without synovial lining and without direct connection to a joint. They often contain blood, hemosiderin, and air. They may develop from synovial cysts.

Both forms appear clinically and radiologically largely identical, hence the terms are used synonymously. Seventy percent of synovial cysts occur between the ages of 25 and 40, more frequently in women than in men. In 16% of cases, they are incidental findings in healthy individuals and cause no symptoms (Goldmann 2013). Diagnosis is usually made via CT or MRI.

Causes can include overuse or previous labrum lesions. The latter occur as a result of trauma or degeneratively in femoroacetabular impingement, where cysts form from the escaped joint fluid.

Therapeutically, the approach depends on size and symptomatology. Small cysts or incidental findings are treated conservatively. Only larger cysts with pain symptoms, movement restrictions, and impingement in the hip joint are treated surgically.

Conservative treatment options include:

- Resting the hip joint

- Anti-inflammatory medications such as ibuprofen or diclofenac

- Physical therapy for pain relief and muscle strengthening

- Injections of hyaluronic acid into the hip joint to reduce friction

- Joint aspiration, though there is a high likelihood of recurrence

- Joint-friendly sports such as swimming, cycling, or walking

Surgical treatment options include:

- Hip arthroscopy for suturing/refixation of the torn labrum in complete tears

- Partial removal (resection) of the damaged parts of the labrum

- Removal of bony overgrowths (offset correction) to prevent further damage

The choice of treatment depends on the extent of the lesion, symptoms, and the patient's activity level. For smaller tears, conservative therapy is initially attempted. For larger tears or labrum detachments, surgical treatment is often necessary.

Citations:

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