A 45-year-old man with a history of recurrent deep vein thrombosis develops splenomegaly. Biopsy shows numerous clear, membrane-bound vacuoles within macrophages that stain positive with periodic acid-Schiff (PAS) and are resistant to diastase digestion. These findings are most consistent with accumulation of:
- A Glycogen
- B Cholesterol
- C Sphingolipid ✓
- D Iron
Correct answer: C. Sphingolipid
Explanation
PAS-positive, diastase-resistant material in macrophages indicates accumulation of a glycolipid or mucolipid, characteristic of sphingolipidoses such as Gaucher disease (glucocerebroside) or Niemann-Pick disease (sphingomyelin). Glycogen is PAS-positive but diastase-sensitive. Cholesterol and iron do not stain with PAS. The clinical picture of splenomegaly with such storage is classic for a lysosomal storage disorder.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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