A 60-year-old woman has a vulvar lesion with pruritus and ulceration. Biopsy shows large cells with pale cytoplasm and vesicular nuclei scattered through the epidermis, predominantly in the basal and parabasal layers. These cells are PAS-positive and diastase-resistant. Which is the most likely diagnosis?
- A Squamous cell carcinoma in situ (Bowen disease)
- B Paget disease of the vulva ✓
- C Malignant melanoma
- D Mycosis fungoides
Correct answer: B. Paget disease of the vulva
Explanation
Paget disease of the vulva shows large pale cells (Paget cells) infiltrating the epidermis, PAS-positive due to mucin content. It represents intraepidermal adenocarcinoma, usually from skin adnexal glands or underlying rectal/genital adenocarcinoma. Bowen disease is squamous CIS without pale cells. Melanoma cells are S100 positive and PAS negative.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.