It is reported in 1% - 3% of all primary breast cancers [2] . About 93% - 100% of MPD cases are associated with underlying breast cancer, usually centrally located close to the areola and often with multiple foci [3] . It is often associated with carcinoma in situ and/or invasive carcinoma of the breast [4] . MPD is often commoner in postmenopausal women in their sixth decades of life, though can be seen in adolescence and elderly patients [5] - [7] .

Mammary Paget’s disease is insidious in onset and appears as a thickened, sometimes pigmented whipping lesion on the nipple, may extend into the areola in centrifugal growth pattern and in advanced cases may involve the surrounding skin ( Figure 1 ). The changes and redness at onset may be mistaken for eczema [4] [8] [9] . Hyper pigmented lesions similar to superficial spreading melanoma have been reported. [3] MPD can also be seen in males but the prognosis is worse compared to females [3] [5] [9] . The lesion is unilateral but rarely bilateral, and may occur in ectopic and accessory nipples [6] [10] [11] [12] . A palpable underlying centrally located lump is seen in 93% - 100% and multifocality of the underlying carcinoma is between 42% to 63% in various studies [13] [14] . Chaudhary et al. reported that 455 of all palpable invasive cancers associated with MPD in their series were found at the upper outer quadrant [15] . Axillary lymph node enlargement may be seen in MPD with lumps [14] . MPD can be identified incidentally in the pathology of a resected mastectomy specimen [4] .

Bilateral mammography [MMG] will show suspicious lesions like masses, micro calcifications, multi-focal lesions and architectural distortions due to multicentricity. [16] [17] The sensitivity of MMG seems higher in the presence of a palpable

mass [16] . In a study MMG identified occult cancer in 8 (15%) out of 52 patients with Paget’s disease [17] . In another study, 65% of MPD patients with negative MMG had an underlying unifocal cancer [18] .

This pathological features and immunohistochemical analysis help in the diagnosis of MPD. Commonly confirmed markers cytokeratin 7 (CK7) and Mucin 1 (MUC1) [1] . Histological sections show stratified squamous epithelium that is intensely infiltrated by malignant epithelial cells. The cells are large, hyper chromatic with marked nuclear pleomorphic, irregular nuclei with prominent nucleoli and abundant pale cytoplasm. The underlying dermis is infiltrated with mononuclear inflammatory ( Figure 2 ). These cells may contain mucin and foamy cells with pale cytoplasm and hyper chromatic nuclei when stained with hematoxylin and eosin [19] [20] .

Patient 1 A 62 years old woman with itchy, discharge and superficial ulceration of left breast. Clinical evaluation confirmed nipple erosion with no palpable lump. Wedged biopsy with histology was consistent with Paget’s disease, mammography didn’t reveal any lesion. Immunohistochemistry shows hormone receptor positive

Treated by neoadjuvant chemotherapy, excision biopsy, radiotherapy, and hormone therapy. Currently on follow-up clinic visits.

Patient 2 A 60 years old woman itchy, superficial ulceration and hyper pigmented right breast. Clinical evaluation revealed an underlying palpable breast mass of 3 cm by 4 cm in diameter. Wedge biopsy with histology was consistent with Paget’s disease, mammography showed underlying breast mass and discreet ipsilateral axillary lymph nodes. Immunohistochemistry is hormone receptor positive.

Treated with neoadjuvant chemotherapy, modified radical mastectomy, adjuvant chemotherapy, radiotherapy, and hormone therapy.

On follow-up clinic visits.

Patient 3 A 70 years old woman with itchy, dry scaly, superficial ulcerated hypo and hyper pigmented left breast nipple and areola region. Clinical evaluation confirmed nipple erosion with no palpable lump. Wedged biopsy with histology was consistent with Paget’s disease, mammography didn’t reveal any lesion. Immunohistochemistry shows hormone receptor positive

Treated by neoadjuvant chemotherapy, excision biopsy, radiotherapy and hormone therapy. Currently on follow-up clinic visits.