Viral, Rickettsial, and Chlamydial Diseases

Verruca vulgaris (VV): the common wart, commonly HPV-2, most common on acral skin of the hands and fingers (1.56). The vulgaris can be left off, except this is used in dermatology to indicate the common prototype of certain disorders (acne vulgaris, lupus vulgaris, psoriasis vulgaris, pemphigus vulgaris, ichthyosis vulgaris, etc).

Plantar wart: located on plantar aspect of the foot (1.48), commonly HPV-1, less papillomatosis, more hypergranulosis.

Myrmecia wart: “ anthill wart “ (Myrmicinae is the subfamily name for fire ants) with tremendous mounds of hypergranulosis and koilocytes resembling specks of dirt of an anthill, HPV-1, mostly on soles and toes.

Filiform wart: more extreme delicate papillomatosis, more on the face.

Verruca plana (flat wart): children or young adults, often face, legs (spread by shaving), commonly HPV-3, often multiple, papules less than 4 mm in diameter with flat-topped smoother surface, may be subtle, minimal papillomatosis and no parakeratosis.

Condyloma acuminatum (venereal wart, plural is condylomata acuminata): genital warts , found on the penis (1.107), vulva (1.149), or groin (1.55), commonly due to low risk HPV-6 and 11 (most common), and 42, 43, and 44. Less often related to oncogenic high risk types 16, or18 (most common), and 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68 which may evolve to Bowen’s disease or bowenoid papulosis (below). Less hyperkeratosis than ordinary warts, more massive acanthosis, and more gentle papillomatosis instead of pointed projections (condyloma means “fist” or “knuckle”). See related discussion of LSIL and HSIL (18.8), Bowen’s disease (18.10) and p16 ( Chapter 30 ). Don’t use the word condyloma by itself because the less common condyloma lata is a completely different entity (12.13). HPV typing by PCR or in situ hybridization can be done from paraffin embedded tissue when it is questionable whether a genital lesion is HPV-induced or not, but technical problems are common, so a negative result might be viewed with skepticism when HPV is strongly suspected. About 40% of vulvar warts in children are thought not likely to be related to sexual abuse, when HPV-2 is found instead of the other types. On adult vulvas, HPV-2 is rare. HPV typing can thus become evidence in legal battles or child abuse accusations.

Condyloma acuminatum after podophyllin application: a pseudomalignancy (1.118), many mitoses arrested in metaphase , which may resemble squamous cell carcinoma or bowenoid papulosis.

Epidermodysplasia verruciformis (EDV): familial (inactivated EVER1 or EVER2 genes) or acquired cellular immunity defect, warts become confluent, mostly HPV-5 or 8 and less commonly many other types, may clinically resemble tinea versicolor or pityriasis rosea (2.4), often bubbly bluish cytoplasm in keratinocytes, sometimes cytologic atypia (hyperchromatic pleomorphic cells), may evolve to squamous cell carcinoma.

Bowenoid papulosis (18.10): condyloma acuminatum in which bowenoid changes are found, often multiple and more brownish papules , more sessile and less acuminate, usually due to HPV-16, -18, or other oncogenic strains, a euphemism for squamous cell carcinoma in situ, but is not usually aggressive. This term is favored by dermatologists who wish to downgrade the significance of these lesions as carcinoma in situ, so that conservative local destruction can be justified. The name is not favored by most gynecologists, gynecologic pathologists, or urologists, some of whom do therapy that is too aggressive.

Pruritic vulvar squamous papillomatosis: small , itchy , subtle papules of the labia minora (1.149), which may appear normal, with variable koilocytic changes, lichenification, submucosal edema, and perivascular lymphocytes, polymerase chain reaction (PCR) may be needed to find HPV, which may not be the cause in all cases.

Focal epithelial hyperplasia (Heck’s disease): HPV-13 or -32 produces multiple papules on the mucosal lip (1.74) or elsewhere in the mouth (1.82), often familial in patients with Native American heritage .

Squamous papilloma: a term used for HPV infection (usually HPV-6 or -11) on mucosal surfaces, such as the conjunctiva, tongue, pharynx, larynx, esophagus, vagina, or anal canal.

Other papillomas (1.102) do not have koilocytes, but this may be confused with other causes of epidermal vacuolization (1.144). Electron microscopy, immunoperoxidase staining, or molecular genetic techniques may be needed if proof of HPV is desired.

Verrucous carcinoma (18.11) is more massive, and bowenoid papulosis (18.10) has more mitoses and cytologic atypia.

Other causes of keratinocyte vacuolization (1.144).

Eczema herpeticum: eczema (2.1) becomes secondarily infected with herpes virus.

Ballooning degeneration to a lesser degree can sometimes be seen in smallpox or vaccinia (14.3) and orf or milker’s nodule (14.5), but multinucleated keratinocytes are rarely seen, and inclusion bodies, if found, are more likely to be intracytoplasmic.

Other acantholytic diseases (1.2) or those with necrotic keratinocytes (1.86).

Other diseases with intraepidermal vesicles (1.147, Chapter 5 ).

Other genital ulcers (12.13).

Herpes simplex and varicella zoster (14.2) exhibit more multinucleated giant cells and the inclusion bodies are intranuclear.

The diagnosis is obvious once molluscum bodies are identified, but they may be sparse in some densely inflamed lesions. Rarely molluscum might be confused with warts (14.1).