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Q1. 56 years old male patient, physical check-up revealed WBC: 50,100/mm³, Hb: 8.8 g/dL; platelet count: 63,000/mm³; Seg: 14%, Lymph: 83%, Mono: 2%, Eo: 1%, Baso: 0%; PE showed a markedly enlarged spleen. Which disease would not typically have these clinical features?

  • (A) Splenic marginal zone lymphoma
  • (B) Follicular lymphoma
  • (C) Hairy cell leukemia
  • (D) B-cell prolymphocytic leukemia
  • (E) Chronic lymphocytic leukemia
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(C) Hairy cell leukemia

詳解

Based on the clinical presentation of a 56-year-old male with marked lymphocytosis (WBC 50,100/mm³ with 83% lymphocytes), cytopenias (anemia and thrombocytopenia), and marked splenomegaly, the question asks which disease would NOT typically have these features.

Why (C) Hairy Cell Leukemia is the CORRECT answer (the FALSE statement)

Hairy cell leukemia (HCL) does NOT typically present with marked lymphocytosis. The hallmark laboratory finding of HCL is pancytopenia with few circulating leukemic cells24. Classic HCL is characterized by cytopenias with a low percentage of leukemic cells in peripheral blood; leukocytosis with more numerous circulating cells occurs in only 10-15% of patients2. Most patients demonstrate significant cytopenias at presentation with leukemic cells often being rare in the peripheral blood4. The characteristic presentation includes pancytopenia, monocytopenia, and splenomegaly—but not the marked lymphocytosis (50,100/mm³ with 83% lymphocytes) seen in this case123.

Figure 1: Pathological and Immunophenotypic Features of Hairy-Cell Leukemia.

Why the OTHER options are INCORRECT (they DO typically have these features)

(A) Splenic marginal zone lymphoma - This entity DOES typically present with lymphocytosis, splenomegaly, and cytopenias. Patients commonly present with splenomegaly, lymphocytosis, and cytopenias as part of the typical clinical picture[^9]. The disease is often discovered incidentally with findings of lymphocytosis or splenomegaly, and symptoms related to cytopenia or massive splenomegaly may be present[7][10].

(B) Follicular lymphoma - Follicular lymphoma can present in a leukemic phase with circulating lymphoma cells, splenomegaly, and cytopenias, particularly in advanced stages with bone marrow involvement. While primarily nodal, leukemic presentation with these features can occur.

(D) B-cell prolymphocytic leukemia - This aggressive leukemia characteristically presents with marked lymphocytosis (often >100,000/mm³), massive splenomegaly, and cytopenias due to bone marrow infiltration. The clinical presentation described in the stem is classic for B-PLL.

(E) Chronic lymphocytic leukemia - CLL commonly presents with lymphocytosis (often marked), splenomegaly, and cytopenias (particularly in advanced stages). This presentation is entirely consistent with CLL, especially Rai stage III-IV or Binet stage B-C disease.

The key distinguishing feature is that HCL typically presents with pancytopenia and few circulating cells (often requiring bone marrow biopsy for diagnosis), whereas all the other options can present with the marked lymphocytosis described in this case.

詳解 · 中文翻譯

根據 56 歲男性患者出現明顯淋巴細胞增多症（WBC 50,100/mm³，淋巴細胞 83%）、細胞減少症（貧血和血小板減少症）和明顯脾腫大的臨床表現，問題要求哪種疾病不通常具有這些特徵。

為何 (C) 毛細胞白血病是正確答案（錯誤陳述）

毛細胞白血病（HCL）不通常呈現明顯淋巴細胞增多症。 HCL 的標誌性實驗室發現是 全血細胞減少症伴循環白血病細胞稀少24。經典 HCL 的特徵是細胞減少症伴 周邊血液中白血病細胞百分比低；僅在 10-15% 的患者中發生白血球增多症與更多循環細胞2。大多數患者在就診時表現出明顯細胞減少症，白血病細胞在周邊血液中常稀少4。特徵性表現包括全血細胞減少症、單核細胞減少症和脾腫大——但不是本病例中看到的明顯淋巴細胞增多症（50,100/mm³，淋巴細胞 83%）123。

為何其他選項錯誤（它們確實通常具有這些特徵）

(A) 脾邊緣帶淋巴瘤 - 此實體確實通常呈現淋巴細胞增多症、脾腫大和細胞減少症。患者通常呈現脾腫大、淋巴細胞增多症和細胞減少症作為典型臨床圖像的一部分[9]。疾病常偶然發現，伴隨淋巴細胞增多症或脾腫大的發現，與細胞減少症或巨大脾腫大相關的症狀可能存在[7][^10]。

(B) 濾泡淋巴瘤 - 濾泡淋巴瘤可呈現為白血症期，伴隨循環淋巴瘤細胞、脾腫大和細胞減少症，特別是在骨髓浸潤的晚期階段。儘管主要是節點性，但可能發生具有這些特徵的白血症表現。

(D) B 細胞前淋巴細胞白血病 - 此侵襲性白血病的特徵是呈現 明顯淋巴細胞增多症（通常 >100,000/mm³）、巨大脾腫大 和由於骨髓浸潤的細胞減少症。題幹中描述的臨床表現對 B-PLL 是經典的。

(E) 慢性淋巴細胞白血病 - CLL 通常呈現 淋巴細胞增多症（常明顯）、脾腫大 和 細胞減少症（特別是晚期）。此表現完全符合 CLL，特別是 Rai 第 III-IV 期或 Binet B-C 期疾病。

關鍵區別特徵是 HCL 通常呈現 全血細胞減少症和循環細胞稀少（常需要骨髓活檢進行診斷），而所有其他選項都可呈現本病例中描述的明顯淋巴細胞增多症。

參考文獻 (AMA)

  1. Falini B, Tiacci E. Hairy-Cell Leukemia. The New England Journal of Medicine. 2024;391(14):1328-1341. doi:10.1056/NEJMra2406376. PMID:39383460. ↩↩

  2. Troussard X, Maître E, Paillassa J. Hairy Cell Leukemia 2024: Update on Diagnosis, Risk-Stratification, and Treatment-Annual Updates in Hematological Malignancies. American Journal of Hematology. 2024;99(4):679-696. doi:10.1002/ajh.27240. PMID:38440808. ↩↩↩↩↩↩

  3. Robak T, Robak M, Majchrzak A, Krawczyńska A, Braun M. Atypical Hairy Cell Leukemia-the Current Status and Future Directions. European Journal of Haematology. 2025;114(5):747-762. doi:10.1111/ejh.14388. PMID:39930768. ↩↩

  4. Cheah CY, Seymour JF. Marginal Zone Lymphoma: 2023 Update on Diagnosis and Management. American Journal of Hematology. 2023;98(10):1645-1657. doi:10.1002/ajh.27058. PMID:37605344. ↩↩↩↩

  5. Rossi D, Bertoni F, Zucca E. Marginal-Zone Lymphomas. The New England Journal of Medicine. 2022;386(6):568-581. doi:10.1056/NEJMra2102568. PMID:35139275. ↩

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