Paget disease of breast vs Paget disease of bone
How to tell Paget disease of breast and Paget disease of bone apart when a board question makes them look alike.
Breast Paget is nipple carcinoma spread; bone Paget is high-turnover disorganized bone remodeling with elevated alkaline phosphatase.
Side by side
Paget disease of breast causes eczematous nipple or areolar changes from malignant cells spreading through lactiferous ducts, often associated with underlying breast carcinoma.
Paget disease of bone causes disorganized bone remodeling with bone pain, enlarged skull, hearing loss, high alkaline phosphatase, and mosaic lamellar bone.
Breast Paget represents intraepidermal spread of ductal carcinoma cells to nipple skin.
Bone Paget has excessive osteoclast activity followed by disorganized osteoblast repair and structurally weak enlarged bone.
Nipple biopsy with Paget cells, underlying DCIS or invasive ductal carcinoma, and unilateral nipple dermatitis support breast Paget.
Isolated high alkaline phosphatase, normal calcium/phosphate, cotton-wool skull, and mosaic bone support bone Paget.
The trap
The shared name hides completely different tissues, mechanisms, and cancer associations.
The repair move
For Paget questions, identify the organ first: nipple epidermis or remodeling bone.
Try a free question
CoreA 58-year-old woman has 6 months of unilateral scaly, eczematous-appearing changes on the right nipple with crusting and erythema that does not respond to topical steroids. Punch biopsy of the nipple shows large cells with abundant pale cytoplasm scattered within the epidermis, staining positive for cytokeratin-7. Mammogram shows underlying microcalcifications. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Paget disease of the breast. Paget disease of the breast is intraepidermal extension of malignant ductal cells (Paget cells) that produces eczematous nipple changes; it is almost always associated with underlying DCIS or invasive ductal carcinoma.
Why the other choices are tempting
- B. Eczema of the nipple is bilateral, responds to topical steroids, and lacks Paget cells on biopsy.
- C. Paget disease of bone is a metabolic bone disorder with elevated alkaline phosphatase, not a skin disease of the nipple.
- D. Nipple psoriasis is typically bilateral with silvery scale and well-demarcated plaques.
- E. Cutaneous candidiasis produces erythema and satellite lesions and responds to antifungal therapy.
Flashcards
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What cancer association supports breast Paget disease?
Underlying ductal carcinoma supports Paget disease of the breast.
What skin finding supports breast Paget disease?
Unilateral eczematous nipple or areolar change supports breast Paget disease.
Quick answers
What is the fastest way to tell Paget disease of breast from Paget disease of bone?
Breast Paget is nipple carcinoma spread; bone Paget is high-turnover disorganized bone remodeling with elevated alkaline phosphatase.
What is the key clue for Paget disease of breast?
Paget disease of breast causes eczematous nipple or areolar changes from malignant cells spreading through lactiferous ducts, often associated with underlying breast carcinoma.
What is the key clue for Paget disease of bone?
Paget disease of bone causes disorganized bone remodeling with bone pain, enlarged skull, hearing loss, high alkaline phosphatase, and mosaic lamellar bone.
What is the common trap with Paget disease of breast vs Paget disease of bone?
The shared name hides completely different tissues, mechanisms, and cancer associations.