Mammary Paget's Disease Mimicking Benign and Malignant Dermatological Conditions: Clinical Challenges and Diagnostic Considerations

Abstract

Mammary Paget's disease (MPD) or Paget's disease of the breast is a rare dermatological malignancy of the nipple-areolar complex that manifests with a spectrum of symptoms spanning from itching and redness to more severe indications such as breast lump, nipple-areolar complex destruction, or nipple discharge. It is predominantly associated with an underlying ductal carcinoma in situ or invasive ductal carcinoma. MPD often masquerades as other benign and malignant dermatological conditions, including eczema, atopic dermatitis, psoriasis, and squamous and basal cell carcinomas, leading to delayed diagnosis and inappropriate treatment. Only one-third of the patients present with a palpable lump; therefore, advanced age with chronic and unilateral lesions should raise concern for MPD. Our review article presents case reports of MPD imitating other skin conditions and underscores the key findings of clinical features and diagnostic workup to help differentiate the condition. A literature review revealed that studies emphasize caution regarding the sole use of mammography and ultrasound in diagnosing MPD, particularly in cases lacking a palpable lump. This highlights the MRI as a superior and more accurate imaging tool. However, any suspicious lesion must be biopsied to allow histopathological and immunohistochemical examination, since there are some cases where MRI findings were negative in the presence of a biopsy-proven MPD. This highlights the need for clinicians to investigate any suspicious lesion of the nipple or breast using the complete triple assessment approach to exclude an underlying malignancy. It is imperative to establish therapeutic guidelines to approach any nipple lesion to minimize the risk of misdiagnosing any underlying cancer, which can be potentially fatal if left alone.

Keywords: ductal carcinoma; eczema; mammary paget's disease (mpd); paget cells; paget's disease of the breast.

Figure 1. MPD with underlying carcinoma

MPD: mammary Paget’s disease Figure made using biorender.com Image Credit: Humza F. Siddiqui

Figure 2. Pathogenesis of MPD

(A) Epidermotropic theory: Paget cells originate in the underlying adenocarcinoma, and neoplastic epithelial cells migrate through the ductal system of the breast to reach the nipple epidermis. (B) Intraepidermal transformation theory: Paget cells originate through degeneration or in situ transformation of epidermal keratinocytes in the nipple-areola complex. MPD: mammary Paget’s disease Image made using biorender.com Image Credit: Humza F. Siddiqui

Figure 3. Diagnostic flowchart of the differential diagnosis of nipple-areola complex diseases

Image Credit: Renee Scott, Sana Altaf, and Kaushik NR