What could be the cause of a large, painful, non-red lesion located between the urethra and vaginal opening?

Large, Painful, Non-Red Lesion Between Urethra and Vaginal Opening

The most likely diagnosis is a Bartholin duct cyst or gland abscess, which should be drained if larger than 2 cm, as these do not resolve spontaneously and commonly recur without intervention. 1

Anatomical Location and Diagnosis

The Bartholin glands are located bilaterally at the posterior introitus, with ducts emptying into the vestibule at approximately the 4 o'clock and 8 o'clock positions—precisely in the area between the urethra and vaginal opening described. 2 These normally pea-sized glands become palpable only when ductal obstruction leads to cyst formation or abscess development. 2

Key Diagnostic Features to Assess

• Size: Measure the largest diameter of the lesion; cysts/abscesses larger than 2 cm require drainage 1
• Color: The absence of erythema (non-red appearance) suggests a cyst rather than an active abscess, as abscesses typically present with surrounding cellulitis and redness 2
• Tenderness: Pain indicates either a large cyst causing pressure or early abscess formation 1
• Fluctuance: Palpate for fluid-filled characteristics typical of cystic lesions 2
• Unilateral vs bilateral: Most Bartholin pathology is unilateral 3

Differential Diagnosis to Consider

While Bartholin duct cyst is most likely given the anatomical location, other vulvar lesions in this region include: 2

• Epidermal inclusion cyst
• Skene's duct cyst (periurethral location)
• Hidradenoma papilliferum
• Lipoma

However, the specific location between urethra and vaginal opening at the posterior introitus strongly favors Bartholin pathology. 4, 2

Management Algorithm

For Cysts >2 cm (Symptomatic and Painful)

Office-based drainage is indicated, as cysts this size do not resolve spontaneously. 1 Treatment options with similar healing and recurrence rates include: 5

1. Word catheter placement (first-line for both cysts and abscesses) 2, 5
2. Marsupialization (for cysts only; contraindicated in active abscess) 2, 5
3. Alcohol sclerotherapy (96% success rate with low recurrence) 3

Critical Management Pitfalls

• Avoid simple needle aspiration or incision and drainage alone—these have significantly higher recurrence rates compared to other methods 5
• Do not marsupialize an abscess—this is only appropriate for cysts 2
• Antibiotics are NOT routinely indicated unless cellulitis is present 2

When to Refer

• Menopausal or perimenopausal women with irregular, nodular Bartholin masses require excisional biopsy to rule out adenocarcinoma 2
• Severe or recurrent infections may require surgical referral 1

Alternative Consideration: Lichen Sclerosus

If the lesion is actually at the urethral meatus rather than posterior to it, and appears as a non-erythematous plaque or pseudocyst, consider lichen sclerosus with clitoral hood adhesions forming a painful pseudocyst. 4 This would present with:

• Porcelain-white plaques or hyperkeratosis 6
• Keratinous debris buildup under adhesions 4
• Obstructive voiding symptoms 6

However, the description of location "between urethra and vaginal opening" anatomically corresponds to the Bartholin gland region, making this the primary diagnosis. 4, 2