Extramammary Paget’s disease

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A rare, slow-growing, usually non-invasive intraepithelial adenocarcinoma outside of the mammary gland and includes Paget’s disease of the vulva and the extremely rare Paget’s disease of the penis.

An epithelium malignant neoplasm in apocrine gland rich skin, including the vulva, scrotum and penis.

Involves primarily the epidermis but occasionally extends into the underlying dermis.

It mimics inflammatory conditions causing a delay in diagnosis.

Has a predilection for apocrine gland bearing areas, mostly the perineum, vulva, axilla, scrotum, and penis.

Is usually seen in isolation and is not usually associated with an underlying invasive malignancy, unlike Paget’s disease of the breast, which is almost always associated with an underlying invasive malignancy.

Considered in any patient with chronic dermatitis of the groin, vulva, or perianal area.

The most common primary location is the vulva, followed by extragenital skin, male genitalia, and perianal skin.

Mimics cutaneous disorders such as intertrigo, dermatitis, or lichen sclerosis.

Diagnoses typically delayed for two years after the onset of symptoms.

The cell of origin is a no unknown but suspected to be apocrine, but intraepithelial keratinocytes and Toker cells are also implicated.

Patients usually present with eczematous lesions in the groin, genitalia, perineum, or perianal area.

The most common symptom is intense pruritus in the affected area and no other symptoms.

Pain and bleeding may occur in long-standing lesions.

Lesions may appear as chronic intertrigo or presumed tinea cruris or eczematous.

Early lesions may be subtle with only slight erythema and crusting.

Maceration of the skin may be noted as may excoriations and lichenification.

Marginated plaque may occur.

A biopsy establishes the diagnosis.

The disease can be single site or multifocal in nature and is well known to the exhibit subclinical spread.

The histology of the lesion is the same as for Paget’s disease of the breast.

Paget’s disease of the vulva, may be a primary lesion or associated with adenocarcinoma originating from local organs such as the Bartholin gland, the urethra, or the rectum and thus be secondary.

Patients tend to be postmenopausal.

Paget’s disease of the penis is rarer than genital Paget’s disease in women.

Approximately 25% of cases are associated with an underlying neoplasm, usually adnexal apocrine carcinoma, but cases of carcinoma of the prostate, urethra, cervix, vagina, endometrium, bladder, and Bartholin’s glands have been described.

Perianal disease is more frequently associated with an underlying carcinoma of the rectum.

Investigation for an underlying carcinoma should be performed.

While Paget disease of the breast is closely associated with an underlying breast cancer in up to 86% of cases, with Extramammary Paget’s disease the association of underlying malignancy is not as well defined, with reported rates varying widely from 4 to 58%.

The diagnosis requires a high degree of clinical suspicion followed by skin biopsy.

Examination should include: full skin examination, rectal examination, sigmoidoscopy, cystoscopy, and additionally women require pelvic examination with a Papanicolaou test, breast examination, and colposcopy.

It is typically confined to in situ disease of the epidermis but can be invasive or arise from pagetoid or upward spread of an underlying malignancy.

It can invade the  dermis and penetrate soft tissues.

Invasive disease can metastasize to regional nodes and other organs.

Usually treated by surgical excision of all the involved epidermis,and is the most effective treatment, but recurrence is common.

Recurrence rate after standard surgical excision is 30-60%.

The average time to recurrence is 2.5 years.

Multiple biopsies performed before surgery may aid in planning initial excision.

Local recurrence rate after excision with Mohs surgery is 8-26%.

Successful treatment with 5-fluorouracil, imiquimod reported.

The prognosis depends on early diagnosis with definitive surgical treatment.

Mortality rates as high as 18% for patients without associated malognancy and 46% for those with underlying carcinoma.

Perianal disease, dermal invasion, and lymph node metastasis are associated with poor prognosis..