Benign Cysts, Rests, and Adnexal Tumors of the Vulva


This chapter addresses benign tumors and cysts that may be seen in the vulva. The most important issues are properly identifying benign lesions and ensuring that they not be confused with malignant neoplasms and vice versa. Mammary type epithelium must be distinguished from neoplasms, and syringomas must be distinguished from basal cell carcinomas. Hidradenomas can be confused with adenocarcinomas, particularly when sclerotic. Exceedingly rare synovial sarcomas can mimic hidradenomas and must be considered in the setting of a deeply situated glandular neoplasm, even when cytologically bland. Attention to these pitfalls, as well as an understanding of the range of benign cysts, is the subject of this chapter.


hidradenoma, ectopic breast tissue, syringoma, Bartholin duct cyst



The clinician and pathologist must recognize benign cysts and adnexal lesions of the vulva to exclude more serious conditions and avoid misclassifying them as malignancies ( Table 5.1 ). They typically do not pose a diagnostic problem with the exception of (1) ectopic breast tissue, particularly when containing fibroadenomas; (2) endometriosis, particularly if it is gland-poor (stromatosis); and (3) hidradenoma papilliferum (HP), which may be interpreted as a malignancy by the uninitiated.

Table 5.1

Benign Cysts, Rests, and Adnexal Tumors of the Vulva

Entity Notes
Bartholin duct cysts and abscesses Posterior introitus; transitional epithelium
Skene duct cyst Near distal urethra; transitional epithelium
Epidermal inclusion cyst (EIC) Associated with prior trauma or circumcision; pseudoepitheliomatous change may mimic neoplasia
Mucinous and ciliated cysts Vulvar vestibule; urogenital sinus origin most plausible; mucinous with squamous metaplasia
Gartner duct cyst Rare in vulva, uncommon in vagina (see Chapter 11 )
Cyst of the canal of Nuck Unilateral labial swelling; cyst on labium majus and femoral region; derived from processus vaginalis
Syringoma Proliferations of adnexal eccrine epithelium separated by fibrous stroma; frequently multiple
Hidradenoma papilliferum (HP) Well-circumscribed painless discrete nodule usually <2 cm; papillary glandular epithelium with myoepithelial cells; may be confused with malignancies
Syringocystadenoma papilliferum Rare benign hamartomatous adnexal tumor of uncertain origin
Anogenital mammary-like glands and associated lesions Rare; may be misdiagnosed as neoplastic with ducts and lobules, but well-circumscribed mass; rarely contains fibroadenoma and phyllodes tumor
Endometriosis May be associated with prior trauma; rarely gives rise to carcinoma
Lymphangioma circumscriptum Numerous small cutaneous vesicles or blebs; dilated lymphatics
Cavernous lymphangioma Presents as a cystic mass
Angiokeratoma Multiple cysts of the vulva

Adapted in part from Heller DS: Benign tumors and tumor-like lesions of the vulva. Clin Obstet Gynecol 58(3):526-535, 2015.

These are covered in recent reviews as well.

Benign Cysts

Benign vulvar cysts generally fall into four categories: Bartholin duct cysts, epidermal inclusion cysts (EICs), mesonephric remnants, and mucous cysts. Additional rare cysts include Skene duct and prolapsed urethral tissue.

Bartholin Duct Cyst

Background and Clinical Presentation

Cysts in the region of the Bartholin gland often involve the duct and are termed Bartholin duct cysts . The orifices of the ducts draining the Bartholin glands are typically located in the posterior introitus (5 o’clock and 7 o’clock positions in lithotomy). Bartholin duct cysts presumably follow obstruction of the duct and may be accompanied by infection and an abscess formation ( Fig. 5.1 ). Rarely these lesions may be detected on imaging.

Fig. 5.1

Clinical appearance of Bartholin duct cyst. The labium minus is located on the middle axis of the cyst.

(Reproduced from Marzano DA, Haefner HK: The Bartholin gland cyst: past, present and future. J Low Genit Tract Dis 8[3]:195-204, 2004.)

Diagnostic Criteria

Histologically, a Bartholin duct cyst is lined by a transitional or squamous epithelium and the specimen often contains associated Bartholin gland ( Fig. 5.2 ). The diagnosis is made by identification of the transitional epithelium and gland (if obtained). Its distinction from a Skene duct cyst is based principally on its posterior rather than periurethral location ( Fig. 5.3 ). The clinical differential diagnosis also includes mucous cysts, EICs, benign adnexal tumors (hidradenoma), and soft tissue tumors, such as lipomas.

Fig. 5.2

A, Microscopic view of the Bartholin duct at the junction of the skin. B, Bartholin duct cyst with squamous metaplasia.

Fig. 5.3

Skene duct cyst on gross examination, located inferior to the left of the urethra.


Traditionally, the management of a Bartholin duct cyst/abscess consisted of insertion of a Word catheter. Another option is marsupialization for Bartholin duct cysts/abscesses. Antibiotic therapy is recommended in the setting of cellulitis. If a cyst recurs after marsupialization, removal of the entire cyst, duct, and gland (if possible) is recommended. As with all cysts, other vulvar neoplasms must be excluded, specifically carcinomas arising in the Bartholin gland or duct (see Chapter 7 ). The latter, however, are extremely rare.

Skene Duct Cyst

Background and Clinical Presentation

The Skene glands (also known as the periurethral glands, lesser vestibular glands, or paraurethral glands ) are located on the anterior wall of the vagina, around the distal part of the urethra (see Fig. 5.3 ). They secrete a viscous lubricating fluid upon sexual arousal, which drains into the urethra and periurethral openings. Skene duct cysts are rare and may occur in newborns, where they present as discrete periurethral pea-size swellings. In adults, they are occasionally reported in association with dyspareunia.

Diagnostic Criteria

Like Bartholin duct cysts, Skene duct cysts are lined by transitional epithelium and in some cases squamous epithelium if sampled near the surface. A variable amount of chronic inflammation is typically encountered.

Differential Diagnosis

The most important distinction is a clinical one between Skene duct cysts and similar entities, such as ectopic ureterocele, urethrocele, urethral diverticula, and benign or malignant urethral and paraurethral tumors.


Management consists of marsupialization or removal of the cyst.

Vulvar Cysts of Urogenital Sinus Origin (Mucous and Ciliated Cysts)

Background and Clinical Presentation

Mucous cysts occur over a wide age range but are usually seen in multiparous women in the third and fourth decades. They present exclusively in the region of the vulvar vestibule and in the majority are solitary lesions of 1 to 2 cm in diameter. They are usually asymptomatic, but patients may complain of pain if the cysts have recently enlarged or impinge on the urethra, where they may cause dysuria.

The origin of mucous cysts has been debated in the past. Theories of origin include invagination of overlying squamous epithelium with mucinous metaplasia, para-mesonephric (müllerian) origin, and origin from urogenital sinus epithelium. The first is unlikely, because most mucous cysts do not communicate with the overlying squamous epithelium, and the squamous differentiation in these cysts is of a metaplastic nature. The paramesonephric origin has been challenged by others who emphasize that the müllerian ducts terminate in the region of the hymen and play no part in the development of the vulvar vestibule. Moreover, the most caudal extension of müllerian epithelium seen in diethylstilbestrol exposure is cephalad to the hymen. Finally, clear cell carcinoma, a tumor arising in müllerian epithelium, has not been reported in the vulvar vestibule. Urogenital sinus epithelium remains the most plausible, inasmuch as both ciliated and mucous cells have been observed in derived epithelium, including the Bartholin gland.

The development of mucous cysts appears to be hormone related in that the lesions occur most frequently in the reproductive years, including during pregnancy.

Diagnostic Criteria

Histologically, mucous cysts contain mucinous epithelium identical in appearance to that lining the endocervix or vaginal adenosis ( Fig. 5.4 ). Less commonly, they contain squamous metaplasia ( Fig. 5.5 ). Ciliated cells have been reported in some cases and may be mixed with the mucinous epithelium.

Fig. 5.4

Mucous cyst beneath the squamous mucosa.

Fig. 5.5

Mucous cyst with squamous metaplasia.

Differential Diagnosis

The differential diagnosis of mucous cysts includes mesonephric remnants (cuboidal epithelium and a fibromuscular wall) and Bartholin duct cysts (transitional epithelium). The labium minus transverses over the middle of the Bartholin cyst.


Mucous cysts are managed by local excision, which is typically for diagnostic purposes.

Epidermal Inclusion Cyst

Background and Clinical Presentation

EICs occasionally occur in the vulvar region and are most commonly associated with prior trauma or circumcision. Vulvar EICs may become infected and management is similar to that of cutaneous EICs ( Fig. 5.6A ).

Fig. 5.6

A, Epidermal inclusion cysts (EICs) on superior vulva. B, At scanning magnification, a true EIC in the dermis with keratinaceous epithelial lining and central loose keratinous debris is noted. C, Higher power shows the squamous epithelial lining. D, Ruptured EICs with pseudoepitheliomatous hyperplasia might mimic a squamous carcinoma.

Diagnostic Criteria

The characteristic histopathologic features are similar to EICs elsewhere, with the cyst wall lined by keratinizing squamous epithelium with a granular cell layer and usually a central collection of keratinous debris (see Fig. 5.6B and C ).

Differential Diagnosis

Ruptured and inflamed EICs may pose a problem in diagnosis. First, the cyst lining may be obscured by the inflammation. In such instances, a careful search for keratin debris in areas of giant cell reaction usually reveals the source. Second, occasionally the inflammatory reaction is associated with a pseudoepitheliomatous change in the cyst lining itself, mimicking a squamous cell carcinoma. The pitfall in this case is the subepithelial location of the changes, which might create diagnostic confusion (see Fig. 5.6D ). Clinically, EICs can also be quite large and mimic clitoromegaly.

Urethral Prolapse

Background and Clinical Presentation

Prolapse of the urethral mucosa through the urethral meatus is not technically a cyst or a neoplasm but may mimic a neoplasm clinically and present with abnormal bleeding. This condition occurs primarily in childhood but may be seen after menopause. It has been linked to lack of estrogen or congenital redundancy of urologic mucosa and loss of support in the urethral tissues. It is often aggravated by increased intra-abdominal pressure. The majority of young patients are younger than 8 years old, with a preponderance of black patients in some series.

Diagnostic Criteria

The clinical diagnosis can usually be made, a malignancy excluded, and biopsy avoided by careful inspection of the location of the lesion and its soft consistency to palpation. If biopsy is performed, histologic examination will disclose benign-appearing transitional epithelium, with nonspecific inflammation, edema, and vascular thrombosis. Ulceration may be present.


Initially, urethral prolapse is treated with medical therapy. This consists of local hygiene with sitz baths and topical antibiotic, steroid, or estrogen creams (two to three times daily for 2 weeks). If that fails and the patient is symptomatic, simple excision of the prolapsed mucosa with careful re-approximation may be performed.

Hydrocele of the Canal of Nuck

Background and Clinical Presentation

A hydrocele of the canal of Nuck is analogous to an encysted hydrocele of the spermatic cord. These hydroceles are derived from the processus vaginalis, and their extent is determined by the degree to which the processus vaginalis remains after birth. Hence, a cyst of the canal of Nuck may present either as a small discrete cystic mass on the labium majus, extending into the femoral region, or as an indirect inguinal hernia, which, in extreme cases, may contain adnexa or other pelvic organs. The persistence of the canal of Nuck may also be responsible for unilateral labial swelling in response to intra-abdominal ascites.

Diagnostic Criteria

Histologically, hydroceles of the canal of Nuck are lined by a single layer of flattened epithelium closely resembling the peritoneal epithelial lining. The cyst wall is composed primarily of fibrous tissue, and bundles of smooth muscle not associated with the cyst wall vasculature have been reported on occasion.

Differential Diagnosis

Hydroceles can usually be distinguished from soft tissue neoplasms, such as lipomas or leiomyomas, by their tendency to transilluminate and the fact that they disappear when adequate pressure is applied to the mass. Bartholin duct cysts can usually be distinguished by their location. Malignant soft tissue masses typically form larger masses and may ulcerate.


The most appropriate approach to the persistent canal of Nuck is removal of the peritoneal-lined sac by ligation/excision.

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Feb 26, 2019 | Posted by in GYNECOLOGY | Comments Off on Benign Cysts, Rests, and Adnexal Tumors of the Vulva

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