Histology USMLE Step 1 Practice Question
A 19-year-old male presents to dermatology with severe acne vulgaris affecting the face, chest, and back for the past 8 months. He reports multiple inflamed papules and comedones that have been unresponsive to topical benzoyl peroxide and clindamycin. Vital signs are stable. A punch biopsy is obtained from an inflamed lesion on the chest. Microscopic examination reveals a ruptured pilosebaceous follicle with sebaceous material in the dermis, surrounded by numerous multinucleated giant cells. Immunohistochemical staining shows CD68 positivity within these multinucleated structures and surrounding mononuclear cells. Which of the following cell types is primarily responsible for the formation of these foreign body giant cells?
Answer choices
- ALangerhans cells responding to antigen presentation
- BMacrophages undergoing fusion in response to persistent foreign materialCorrect answer
- CActivated fibroblasts producing collagen around the follicular rupture site
- DNeutrophils recruited from the peripheral circulation during acute inflammation
- ESebaceous gland epithelial cells attempting follicular repair
- FMast cells degranulating to recruit additional immune cells
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