A 65-year-old woman had a chalazion of the left upper lid repeatedly excised over 18 months, each time recurring at the same site. The lesion now appears as a firm, yellowish, non-tender nodule with loss of lashes. Biopsy shows pagetoid spread of atypical cells positive for oil red O stain. The MOST likely diagnosis is:
- A Seborrheic keratosis
- B Squamous cell carcinoma
- C Sebaceous gland carcinoma ✓
- D Merkel cell carcinoma
Correct answer: C. Sebaceous gland carcinoma
Explanation
Sebaceous gland carcinoma classically masquerades as a recurrent chalazion or chronic blepharitis in elderly patients. Oil red O staining highlights intracellular lipid, and pagetoid spread into the conjunctival epithelium is characteristic, sometimes requiring map biopsies. Squamous cell carcinoma lacks lipid, Merkel cell carcinoma arises as a rapidly growing violaceous nodule, and seborrheic keratosis is a benign lesion.
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.