EXTERNAL GENITAL WARTS – CLINICAL PRESENTATION AND DIAGNOSIS

Genital warts are visible lesions that occur in the anogenital area and there is good correlation between physical findings and histological studies.

There are four variants of genital warts:

1. Skin-coloured filiform warts (condyloma acuminata) occur on moist mucosal skin.
2. Skin-coloured raised papules with a rough warty surface (verruca vulgaris) arise on drier areas of genital skin.
3. On either dry or moist skin, smooth flat-topped papules which may be pink, red, brown or black, can develop (carpet warts).
4. Giant condyloma up to 4cm in size with a cauliflower surface and red or pink in colour usually arise on dry genital skin.(48)

Genital warts are frequently multifocal (one or more lesions at one anatomic site, e.g. vulva), or multicentric (lesions on disparate anatomic sites, e.g. perineum and cervix).(49-51) It is important to examine the entire lower genital tract for the presence of multicentric visible warts before treatment.

Perianal lesions are common in both sexes, including heterosexual men. They are not exclusively associated with anal sex, due to the regional spread of HPV infection. They are, however, seen more commonly in MSM.

Lesions can also occur on the vagina, cervix, urethral meatus and anal canal.

Differential diagnosis

Most warts are clinically recognisable. However, some require examination under magnification (e.g. with a dermatoscope or colposcope) to distinguish from other lumps (e.g. vestibular papillomatosis or molluscum contagiosum). For many patients, the psychological impact of warts is significant. If the diagnosis is uncertain, it is useful to get a second opinion (either from a colleague or a specialist).

The differential diagnosis of genital warts includes:

• Normal anatomic variants in women such as vestibular papillae, prominent sebaceous glands (Fordyce spots) and skin tags (acrochordans).
• Normal anatomic variants in men such as sebaceous glands (Tyson’s glands), pearly penile papules, skin tags, angiofibroma.
• Infections such as molluscum contagiosum, condylomata lata (syphilis).
• Dermatoses and benign neoplasms such as seborrhoeic keratoses, melanocytic naevus, angioma, lymphangioma, psoriasis and lichen planus.
• High-grade squamous intraepithelial lesion (HSIL) (previously called VIN, vulval intrapepithelial neoplasia).(52) HSIL usually presents as white, red or pigmented papules or plaques which may be pruritic, but can be asymptomatic. The lesions may have a warty surface and can be unifocal or multifocal. A lesion may be small and discrete or may be an extensive plaque covering most of the vulval or perianal skin. It may be clinically indistinguishable from the papular form of external genital warts, but appears more disorganised.(53,54) Histological examination of these lesions shows high-grade intraepithelial neoplasia. HSIL is usually associated with HPV type 16 infection.
• Vulval cancer. This may arise from HSIL as a tumour or ulcer.

A number of clinical variants of PIN are recognised; many are associated with HPV type 16 (55) (see Clinical Presentations of Anogenital HPV for pictures).

Penile and anal cancer usually present as a small nodule which may be ulcerated. Untreated, it will progress to a large ulcerated plaque. On the penis the most common sites are the glans, coronal sulcus and prepuce.