Colposcopy of the Vulva

Chapter 8


Colposcopy of the Vulva




8 Colposcopy of the Vulva


8.1 Histology of the Vulva


The vulva is covered by three types of squamous epithelium:


Keratinized skin with hair follicles, sebaceous glands, and apocrine and eccrine sweat glands. This type of skin covers the mons pubis and the labia majora.


Modified mucosa with sebaceous glands but no hair follicles or sweat glands; no cornification on the interlabial sulci covers the outer aspect of the labia minora and the clitoris.


Glycogen-containing mucosa without sebaceous or sweat glands, hair, or cornification covers the inner aspect of the labia minora and the introitus (Fig. 8.1).


The transition between the keratinized and nonkeratinized epithelia (Hart’s line) is sometimes visible to the naked eye and always visible microscopically. Hart’s line is best seen at the posterior fourchette, and it marks the peripheral border of the vaginal vestibulum. The vaginal vestibulum comprises the outer aspect of the hymen, which separates the vestibule from the vagina, the frenulum clitoridis, the inner aspect of the labia minora, the vaginal introitus, and the external urethral orifice.


The epidermis is a stratified squamous epithelium composed of distinct layers. In a vertical section, the epidermis has an undulating appearance caused by the malpighian rete. The deepest layer, resting on the basement membrane, is the basal cell layer (germinative layer, stratum germinativum) from which the epithelium regenerates. The basal cells are undifferentiated and pluripotent. The basal layer also contains melanocytes, which are highly differentiated. The spinal cell layer (stratum spinosum) is the layer most variable in thickness. The next layer, the granular layer (stratum granulosum), is followed by the horny layer (stratum corneum), which also varies in thickness.


A variant of normal is the so-called micropapillomatosis. These are prominent, 1- to 3-mm vestibular papillae (Fig. 8.2), which are a common finding in premenopausal women and are not to be confused with condylomas. Micropapillomatosis can also be found at the inner aspect of the labia minora and at the external edges of the vestibule.


The glycogen-containing mucosa of the introitus and the vagina has the same appearance as the cervical epithelium and is very sensitive to hormonal influences. With lack of estrogen in childhood and after menopause, this layer is thin. With exposure to estrogen, the mucosa gains its characteristic multilayered appearance. Apart from the basal cell layer, which does not contain melanocytes, the next cell layers are generally uniform. All contain glycogen in the cytoplasm, which gives it a honeycomb appearance in hematoxylin–eosin sections. Apart from the basal cell layer, one can distinguish only an intermediate and a superficial cell layer.


The vulva can be affected nonspecifically by dermatologic conditions and by specific conditions. The vulva is an epithelial high-risk area with a predisposition to multifocal and recurrent malignant transformation.




8.2 Diagnostic Methods for Evaluating Vulvar Lesions


The diagnosis of vulvar disorders is based on the clinical history, inspection, palpation, colposcopy, histology, and, in some instances, confirmation with laboratory evaluation, including biomarkers.


8.2.1 History and Symptoms


In younger patients, the history is often brief and related to an acute condition. Older patients frequently have chronic lesions, and sometimes there is a marked discrepancy between the subjective complaints and the objective findings. Characteristic symptoms of vulvar lesions are itching (pruritus), soreness, burning sensations, paresthesias, and pain, including dyspareunia. The relevant surgical, medical (diabetes), and psychiatric history should be elicited. Medications, estrogen replacement, allergies, incontinence, and prior vaginitis and sexually transmitted diseases are of interest.


8.2.2 Inspection


Diseases of the vulva vary and overlap in appearance. Some patients have multiple conditions. Biopsy and histopathology are required for most diagnoses. Vulvar lesions that do not resolve within weeks of medical management have to be watched closely to detect progression. Photographic documentation is very helpful (Table 8.1).


8.2.3 Palpation


Many vulvar conditions are normal to palpation. However, even small invasive carcinomas show a tougher consistency around their base than the surrounding tissue. Small invasive foci may, on occasion, be suspected in large areas of abnormal findings by palpation alone. When these lesions grow, they are no longer at the level of the surrounding tissue and become less mobile against the dermis. The surface of vulvar conditions can also be smooth or rough on palpation; a rough surface is often due to either crust or scale.


8.2.4 Toluidine Blue Test (Collins’ Test)


This technique, now rarely used, consists of 1% toluidine blue dye applied to the vulva for 2 to 3 minutes and then washed off with 1% acetic acid (Fig. 8.3). The toluidine blue test can also be used during surgery to plan the margins of the excision. However, the test has become almost obsolete with the increased use of colposcopy with acetic acid. Colposcopy (vulvoscopy) provides much more detail, particularly for papillary lesions and the typical findings of punctations and mosaics. Toluidine blue is sometimes applied for forensic purposes to demonstrate injuries.


8.2.5 Colposcopy of the Vulva


Magnification of the vulvar skin with or without the application of acetic acid permits more precise evaluation and earlier detection of vulvar lesions than inspection with the naked eye. In contrast to colposcopy of the cervix, low magnification usually suffices.


Color can be described as red (erythroplakia), white (leukoplakia), or pigmented (melanotic). Skin-colored lesions are those that match the color of the surrounding normal skin. In the mucosal portion of the vulva, skin-colored lesions will be pink or red. Evaluation of color does not require colposcopy.


Redness (erythroplakia) can be due to acute or chronic inflammation, squamous intraepithelial lesions (SIL), differentiated-type vulvar intraepithelial neoplasia (dVIN), or invasive neoplasia. Erythroplakia can be circumscribed or diffuse (Figs. 8.4 and 8.5).


Leukoplakia is a general descriptive term for whitish lesions before application of acetic acid. It is caused by thickening of the superficial keratinized epithelial layers. Whiteness can be caused by dermatoses such as lichen sclerosus or lichen planus with decreased blood supply and hyperkeratosis as well as with malignant and premalignant conditions (Figs. 8.68.8).


Dark (melanotic) lesions: Apart from the lesions of malignant melanoma and its precursors, about 30% of all high-grade SIL (HSIL) are associated with irregular hyperpigmentation (Fig. 8.9).


Colposcopy of the vulva is used for the following:


• To define the extent of lesions.


• To direct biopsies to the area of the most clinically severe abnormality.


• To exclude overt invasive cancer.


• To direct treatment by visualizing anatomic landmarks.


The 2011 IFCPC Clinical/Colposcopic Terminology of the Vulva distinguishes normal findings, abnormal findings, miscellaneous findings, findings suspicious for malignancy, and abnormal colposcopic (magnification) findings. Sharp borders are also important. Mosaic is not included in the new terminology, although it can be detected in vulvar lesions. The vulvar terminology does not distinguish between minor and major abnormal colposcopic findings, as it does for the cervix and vagina.


Acetowhite epithelium. In contrast to the cervix, where acetic acid is an integral part of the examination, on the vulva, acetic acid is applied only when morphologic manifestation of HPV infection (SIL) or early invasive disease linked to high-risk HPV is suspected. Application of 3 to 5% acetic acid requires 2 to 3 minutes for lesions to become apparent.


Table 8.1 Secondary morphology presentation





























Type of lesion


Comment


Eczema


A group of inflammatory diseases that are clinically characterized by the presence of itchy, poorly marginated red plaques with minor evidence of microvesiculation and/or, more frequently, subsequent surface disruption


Lichenification


Thickening of the tissue and increased prominence of skin markings. Scale may or may not be detectable in vulvar lichenification. Lichenification may be bright red, dusky red, white, or skin-colored


Excoriation


Surface disruption occurring as a result of the “itch–scratch cycle”


Erosion


A shallow defect in the skin surface; absence of some, or all, of the epidermis down to the basement membrane; the dermis is intact


Fissure


A thin, linear erosion of the skin surface


Ulcer


Deeper defect; absence of the epidermis and some, or all, of the dermis





It is important to carefully inspect the vulva before acetic acid is applied in order to outline preexisting areas of leukoplakia. Diffuse and flat acetowhite epithelium can represent a normal finding that is most likely due to increased cell turnover secondary to mechanical stimuli or inflammatory conditions of the vulva. Flat acetowhite epithelium therefore should be considered nonspecific. In contrast, acetowhite epithelium from HSIL is more likely to be raised and sharply demarcated. The results after application of acetic acid are interpreted in combination with other signs such as punctation, mosaic, sharp borders, elevated lesions, and atypical vessels (Fig. 8.10).


Punctation and mosaic. Acetowhite epithelium, erythroplakia, and leukoplakia can show mosaics and punctations when studied with the colposcope. They are more common in the nonkeratinizing, glycogen-containing squamous epithelium of the introitus than in the remaining vulva (Figs. 8.118.14).


Sharp borders. Border zones (margination) represent the transition from normal skin to lesional skin. A sharply marginated lesion has an abrupt transition; a poorly marginated lesion has a more gradual transition. HSIL are often sharply demarcated from their surrounding normal epithelium, as are different types of abnormal epithelia among themselves (Fig. 8.15). The larger the difference in the differentiation of areas of adjoining HSIL, the clearer the border between them. In contrast, inflammation affects the stroma more than the epithelium and its borders are much less defined. Sharp demarcation is seen with carcinomas of all sizes (Fig. 8.16).


Surface irregularities. Leukoplakias with a rough and irregular surface are suspicious for dVIN (see section 8.3.2).


Atypical vessels. As at other locations, atypical vessels are suggestive of invasive lesions (Fig. 8.17).



The 2011 IFCPC terminology for the vulva distinguishes primary lesion types (Table 7.5) and secondary presentations (Table 8.1). These lesions can be evaluated with the naked eye, a magnifying glass, or a colposcope with low magnification.


8.2.6 Assessment of Colposcopic Findings


Acetowhite epithelium. Sharply demarcated and raised acetowhite epithelium generally corresponds to HSIL, whereas dVIN generally does not react to acetic acid.


Leukoplakia and erythroplakia. SIL and dVIN can cause marked hyper/parakeratosis visible as leukoplakia or inflammation and hypervascularization visible as erythroplakia. There are also erythroplakic areas in atrophic glycogen-containing squamous epithelium.


Punctation and mosaic. Punctations and mosaics in nonmalignant lesions correspond to thin epithelial ridges and wide stromal papillae. In premalignant and malignant lesions, the stromal papillae are much narrower and the epithelial ridges plumper and more irregular. In vertical sections, the differences between normal and atypical squamous epithelium are even more apparent. Papillae and papillary ridges of considerable height can be seen in hyperplastic epidermis as well as in all types of SIL. High and thin stromal papillae in papillary low-grade SIL (LSIL) are especially well seen. Papillomatous HSIL often show marked but irregular stromal papillae.













8.2.7 Biopsy


Biopsy should be performed on all suspicious lesions of the vulva, including white, gray, red, pigmented, or raised lesions and all conditions that do not resolve promptly with medical treatment. If the lesion is uniform, a single biopsy suffices. If the lesion is multifaceted, two or more biopsies should be obtained. In ulcerative lesions, a biopsy at the periphery can avoid nonrepresentative necrosis.


Biopsies can be performed quickly and simply with local anesthesia (lidocaine with or without adrenaline or topical lidocaine cream) on an outpatient basis using just a few instruments (Fig. 8.18). The hands of the patient can help expose the lesion. A 5-mm punch biopsy perpendicular to the surface is ideal. The defect on occasion requires a fine resorbable suture for hemostasis. Ideally, anticoagulants are discontinued before biopsy.


8.2.8 Exfoliative Cytology


Cytology has poor sensitivity and specificity for the detection of SIL. Liquid-based cytology may provide better results than conventional cytology, especially at the mucosal side of the vulva. Cytology is inadequate in the detection of dVIN, Paget’s disease, and melanoma in situ.


8.2.9 HPV Testing


HPV testing permits differentiation between low-risk and high-risk infections as well as between (pre) neoplastic conditions associated with HPV and lesions not associated with HPV. HPV testing is also important to define the risk of progression in LSIL because LSIL containing low-risk HPV is histologically indistinguishable from LSIL containing high-risk HPV. HPV testing has a role in the follow-up of patients after treatment for HPV-positive lesions (Figs. 8.19 and 8.20).


Apr 16, 2018 | Posted by in OBSTETRICS | Comments Off on Colposcopy of the Vulva
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