What are the differential diagnoses and treatment options for swollen lumps on the labia?

Differential Diagnoses for Swollen Labial Lumps

The most common causes of swollen labial lumps include Bartholin gland infections/cysts, lichen sclerosus, hernias containing pelvic organs, lipomas, and sexually transmitted infections—each requiring distinct diagnostic and management approaches based on clinical presentation.

Infectious Etiologies

Bartholin Gland Pathology

• Bartholin gland infections present with unilateral swelling, erythema, and tenderness that extends into the entire labia minora, representing one of the most common infectious causes 1
• Any vaginal organism can cause infection, but STI pathogens including gonorrhea and chlamydia are common culprits and must be tested for with nucleic acid amplification tests 1, 2
• The swelling typically localizes to the posterior-lateral aspect of the introitus but can involve broader labial tissue 1

Viral and Bacterial STIs

• Herpes simplex virus causes vulvar swelling accompanied by painful ulcerations—viral culture for HSV should be performed when ulcerations are present 1, 2
• Syphilis manifests as flesh-colored papules that may be confused with warts, requiring serologic testing with confirmatory treponemal testing 1, 2
• Gonorrhea and chlamydia may present with inflammation and swelling even without obvious Bartholin involvement 1

Dermatologic and Inflammatory Conditions

Lichen Sclerosus (Critical Diagnosis)

• Lichen sclerosus presents as porcelain-white papules and plaques with areas of ecchymosis affecting the interlabial sulci and labia minora 1
• This condition has a bimodal presentation peaking in prepubertal girls and postmenopausal women 1, 2
• The main symptom is pruritus, but pain occurs with erosions or fissures 1
• Biopsy is mandatory as the first diagnostic step due to 3.5-5% malignant transformation risk to squamous cell carcinoma 2
• Lichen sclerosus may have an autoimmune etiology with associations to other autoimmune diseases requiring assessment 1, 2

Contact Dermatitis

• Contact dermatitis and allergic reactions cause inflammation with redness and swelling 1
• Hypopigmentation changes may accompany chronic inflammation 1

Structural and Anatomic Causes

Hernias

• Inguinal herniation of the ovary or uterus presenting as a labia majora mass is a rare congenital condition that may be complicated by strangulation, torsion, and infertility 3
• Sonography plays a crucial diagnostic role in identifying herniated pelvic organs within labial masses 3
• The differential for labial masses in prepubertal females includes inguinal hernia, hydrocele of the canal of Nuck, congenital labial cysts, and other masses 3

Lipomas

• Lipomas are common benign adipose tissue tumors but are infrequently found in the labia majora, especially at large size 4
• Imaging methods are essential for diagnosis and to differentiate from liposarcoma or omental herniation into Nuck's canal 4
• Surgical management is effective for large lipomas with attention to both medical and aesthetic outcomes 4

Labial Hypertrophy

• Labia minora or majora hypertrophy can be congenital or acquired by chronic irritation, exogenous androgenic hormones, or stretching 5, 6
• This represents a variation of normal anatomy rather than true pathology in many cases 7
• Enlarged labia can cause functional problems including inflammation, poor hygiene, and interference with activities 6

Traumatic Causes

Piercing Complications

• Labia minora piercings can develop infection, pain, bleeding, hematoma formation, or allergic reactions during the healing period 1
• Multiple adverse outcomes including cyst formation and hypertrophic scarring can cause persistent swelling 1

Critical Diagnostic Algorithm

Immediate Assessment Steps

1. Document duration, pattern, unilateral versus bilateral presentation, and associated symptoms (pruritus, pain, discharge) 2
2. Assess sexual history and STI risk factors to identify infectious causes 2
3. Examine for characteristic findings: porcelain-white plaques (lichen sclerosus), fluctuant mass (Bartholin cyst/abscess), reducible mass (hernia), ulcerations (HSV, syphilis) 1, 2

Mandatory Testing

• STI testing including gonorrhea and chlamydia nucleic acid amplification tests for all sexually active patients 2
• Viral culture for HSV when ulcerations present; serologic testing for syphilis when papules present 2
• Biopsy of any chronic, white, or suspicious lesions to confirm lichen sclerosus and rule out malignancy 2
• Ultrasound for masses in prepubertal patients or when hernia suspected to identify herniated organs 3

Baseline Laboratory Studies

• CBC and metabolic panel to assess for potential complications, particularly when systemic symptoms present 2
• Assessment for autoimmune disease history in suspected lichen sclerosus 2

Critical Pitfalls to Avoid

• Do not dismiss ecchymosis in prepubertal girls as definitively indicating sexual abuse without considering lichen sclerosus as a benign cause 1
• Always assess for STI pathogens when Bartholin or Skene gland infections are present—do not assume non-STI etiology 1, 2
• Never delay biopsy of chronic white lesions given malignancy risk in lichen sclerosus 2
• Do not assume labial enlargement is pathologic without considering normal anatomic variation 7
• Perform imaging before assuming a labial mass is simply hypertrophy—hernias require different management 3