Tartrate-resistant acid phosphatase (TRAP) staining positivity in neoplastic cells is a classic diagnostic feature of which haematological malignancy?
- A Chronic lymphocytic leukaemia
- B Hairy cell leukaemia ✓
- C Multiple myeloma
- D Acute promyelocytic leukaemia
Correct answer: B. Hairy cell leukaemia
Explanation
The abnormal B cells of hairy cell leukaemia are characteristically strongly positive for tartrate-resistant acid phosphatase, a property retained even after treatment with tartrate, which suppresses the ordinary acid phosphatase isoenzymes found in other lymphocytes. Modern diagnosis relies on flow cytometry demonstrating CD11c, CD25, and annexin A1 expression, but TRAP positivity remains a classical examination-linked diagnostic clue. CLL cells are TRAP negative, and APL is defined by t(15;17) rather than enzymatic staining.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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