A 53-year-old woman comes to the office due to an itchy rash she has had on her left breast for the past month. The patient has applied over-the-counter corticosteroid ointment with no relief of symptoms. The patient's last menstrual period was 2 years ago. She has a history of hypertension that has improved with weight loss and exercise, and she takes no prescription medications. Physical examination shows an eczematous plaque on the left nipple and areola. The remainder of the physical examination is unremarkable. Histologic examination of the skin lesion would most likely show which of the following?
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This patient likely has Paget disease of the breast (PDB), a malignant breast condition characterized by a unilateral, painful/pruritic, eczematous rash confined to the nipple and areola. Associated scaling and ulceration are also frequently seen.
PDB is diagnosed by tissue biopsy (eg, wedge, punch) that reveals Paget cells in the epidermis of the nipple-areolar complex. Paget cells are malignant, intraepithelial adenocarcinoma cells that appear enlarged with abundant cytoplasm and prominent nucleoli on microscopy. These cells and associated skin changes are thought to be caused by the spread of an underlying breast malignancy (eg, intraductal carcinoma, ductal carcinoma in situ) to the nipple surface via the mammary ducts, resulting in the eczematous nipple rash.
Because approximately 85% of patients have an underlying breast malignancy, all patients with PDB require diagnostic mammography even without a palpable breast mass.
(Choice B) Cutaneous angiosarcoma, which can arise in the radiation field following radiotherapy for breast cancer, typically presents as purple papulonodular lesions and bruise-like patches. Microscopy often shows anastomosing vascular channels infiltrating the dermis lined by atypical (ie, large, hyperchromatic) endothelial cells.
(Choice C) Fibroadenomas are small, firm, mobile breast masses that occur due to the proliferation of breast stroma and epithelium. Fibroadenomas are benign, and microscopy typically shows stromal proliferation compressing the breast ducts.
(Choice D) Breast lymphoma is extremely rare and typically presents as a painless, palpable breast mass without cutaneous manifestations in a postmenopausal woman. Moreover, cutaneous lymphomas typically involve the trunk and/or extremities rather than the breast.
(Choice E) Intraductal papillomas of the breast typically present with unilateral, bloody nipple discharge with no associated breast masses or skin/nipple changes. Microscopy shows papillae composed of epithelial and myoepithelial cells, which line a fibrovascular core.
Educational objective:
Paget disease of the breast is a malignant breast condition characterized by a unilateral, painful/pruritic, eczematous rash on the nipple/areolar skin. Diagnosis is with biopsy showing the infiltration of the nipple/areolar epidermis by Paget cells (intraepithelial adenocarcinoma cells).