Mammary Paget disease
* Synonym: Paget disease of the breast and Paget disease of the nipple.
* An uncommon skin cancer characterized by a chronic eczema-like rash of the nipple and adjacent areolar skin. It is caused by the invasion of the epidermis by cells from an underlying intraductal carcinoma of the breast (Paget cells).
* Age: Most commonly between 50 and 60 years of age.
* Sex: women > men (very rare in men)
* Usually Mammary Paget disease is associated with an underlying breast adenocarcinoma.
* Between 1% and 4% of breast carcinomas present with PD.
* About 5% of patients have PD without confirmed evidence of underlying carcinoma, and the remaining 95% have either an invasive or an intraductal carcinoma.
* Sometimes it is difficult to detect underlying breast Ca on clinical examination or by mammogram.
* In rare cases, even when no underlying carcinoma is found on surgical removal, the sentinel node may be positive.
* Extramammary Paget disease is a similar condition that involves the skin of female and male genitalia.
Clinical Presentation:
* Most patients present with an itchy, burning erythematous rash on and around the nipple area. There may be swelling, oozing nipple discharge, bloody nipple discharge, scaling, ulceration and an inversion (retraction) of the nipple. The condition usually is sharply marginated and in most cases unilateral and recalcitrant to treatment (only one nipple is affected although rare cases of involvement of both nipples have been seen).
* In advanced cases, a subjacent mass and ipsilateral axillary adenopathy may be palpable.
* At times, PD may be hyperpigmented and may mimic melanoma.
Differential Diagnosis:
Clinically:
1. Eczema: Atopic eczema, contact eczema and LSC.
2. Papillary adenoma of the nipple.
3. Hyperkeratosis of the nipple and areola (Unilateral).
Histopathologically:
1. Pagetoid melanoma.
2. Bowen’s disease.
Diagnosis:
It is confirmed by skin biopsy of the lesion which reveals the presence of Paget cells: large, round, pale-staining cells with large nuclei. Intercellular bridges are absent. The cells appear singly or in small nests between the squamous cells. Atypical cells may be “spat out” into the stratum corneum. Frequently, a layer of basal cells separates the Paget cells from the basement membrane and is seen crushed beneath the nests of Paget cells. This histologic feature helps to distinguish PD from pagetoid melanoma and Bowen’s disease. In the dermis, an inflammatory reaction is often present.
Paget cells have characteristic staining profile being positive to many cell markers.
Skin biopsy may also determine whether there is underlying cancer, although some breast carcinomas are not seen because they are situated more deeply in the breast tissue.
A mammogram may accurately locate the underlying Ca prior to breast biopsy.
Treatment:
Mastectomy (removal of the breast) is often necessary. Alternatively, it can be widely locally excised along with samples of tissue taken from nearby lymph nodes in the armpit. Sometimes conservative treatment such as partial nipple excision, wedge excision, cone excision, radiotherapy, or a combination of these may be used in women with less advanced stages of the disease. However, recurrence is common in these cases.
* Prognosis: Depends on extent of tumor invasion.
Patients presenting with a palpable breast mass typically have more advanced disease and lower 5-year survival.