I have a cyst on the external vulva (outside the labia); how should it be evaluated and managed?

Evaluation and Management of External Vulvar Cysts

A cyst on the external vulva should be initially evaluated with physical examination to characterize its features, followed by translabial or transvaginal ultrasound if imaging is needed, with management ranging from observation for small asymptomatic lesions to surgical excision for symptomatic or concerning masses. 1

Initial Clinical Assessment

Physical examination is the foundation of diagnosis for vulvar cysts and determines whether imaging is necessary. 1 During examination, specifically assess:

• Size of the cyst (measurements in centimeters) 2
• Mobility versus fixation to underlying structures 2
• Presence of pain, tenderness, or signs of infection 3, 2
• Surface characteristics (smooth versus irregular) 2
• Associated symptoms including bleeding or discharge 2
• Patient age (cysts in women >40 years require heightened attention for malignancy risk) 2

When to Obtain Imaging

Ultrasound is the initial imaging study of choice when physical examination findings are abnormal or the diagnosis is uncertain. 1 Specifically:

• Translabial or transvaginal ultrasound (or both) appropriately evaluates perineal and vaginal cysts that are subcutaneous but palpable 1
• Color Doppler should be included as a standard component to evaluate internal vascularity and distinguish cysts from solid tissue 1
• Combined transabdominal and transvaginal approach provides both anatomic overview and superior spatial resolution 1

MRI with gadolinium contrast is reserved for problem-solving when ultrasound identifies a mass requiring additional characterization, particularly to evaluate for enhancing soft-tissue components that might suggest infection or neoplasia. 1 MRI provides crucial anatomic detail for surgical planning but is not indicated as the initial imaging study. 1

CT has no role in primary evaluation of vulvar cysts. 1

Management Based on Clinical Features

Small, Asymptomatic Cysts

• Observation without intervention is appropriate for benign-appearing, asymptomatic cysts 2
• No routine imaging or follow-up is required for clearly benign lesions on examination 2

Symptomatic Cysts

• Surgical excision is indicated when cysts cause pain, discomfort, or impact quality of life 3, 4
• Complete excision has a high success rate and is the definitive treatment 2, 4
• Marsupialization may be appropriate for certain cyst types (particularly Bartholin's duct cysts) to preserve gland function 5

Concerning Features Requiring Specialist Referral

Refer to gynecology or gynecologic oncology when:

• Cysts in women >40 years (higher malignancy risk) 2
• Fixed or immobile masses 2
• Associated pain or bleeding 2
• Irregular or nodular appearance 5
• Rapid growth or changing characteristics 4

Common Pitfalls to Avoid

• Do not assume all vulvar masses are Bartholin's cysts – the differential includes epidermal inclusion cysts, Skene's duct cysts, mucinous cysts, hidradenoma papilliferum, and lipomas 5, 6
• Do not perform fine-needle aspiration of vulvar cysts, as this is contraindicated 7
• Do not dismiss masses in perimenopausal/postmenopausal women – excisional biopsy may be needed to rule out adenocarcinoma 5
• Do not overlook extension into deep perineal tissue – MRI is valuable for assessing depth and extent of large masses before surgery 6

Specific Cyst Types and Their Management

Bartholin's duct cysts/abscesses (located at 4 and 8 o'clock positions at posterior introitus):

• Word catheter insertion for office-based drainage 5
• Marsupialization for cysts (not abscesses) 5
• Antibiotics only when cellulitis is present 5

Epidermoid cysts:

• Total surgical excision is the definitive treatment 6
• MRI helpful for giant lesions to assess deep tissue extension 6

Mucinous cysts:

• Observation if asymptomatic 4
• Surgical removal if symptomatic due to size 4
• Long-term surveillance for recurrence after excision 4