Basanti, a 30yearold girl, presents with complaints of fever and weakness. On examination there is splenomegaly of 3 cm below the costal margin. Hb is 8 gm/ dL. TLC is 3, 000/ mm3, platelet count is 80, 000 mm3. Which of the following is the LEAST likely diagnosis: March 2013

**Core Concept**
The patient's presentation with fever, weakness, splenomegaly, anemia, leukocytosis, and thrombocytopenia suggests a hematological disorder. The differential diagnosis includes infectious, inflammatory, and neoplastic conditions affecting the bone marrow.

**Why the Correct Answer is Right**
The correct answer is the diagnosis that is least likely to present with these specific laboratory and clinical findings. The patient's anemia (Hb 8 gm/dL) and leukocytosis (TLC 3,000/mm3) suggest a reactive process, while the thrombocytopenia (platelet count 80,000/mm3) could be due to splenic sequestration or bone marrow infiltration. The presence of splenomegaly further supports a diagnosis involving the spleen or bone marrow.

**Why Each Wrong Option is Incorrect**
**Option A:** Chronic Myeloid Leukemia (CML) - CML can present with anemia, leukocytosis, and thrombocytosis, but the thrombocytopenia in this case makes it less likely.

**Option B:** Sickle Cell Disease - Sickle cell disease can cause anemia and splenomegaly, but the leukocytosis and thrombocytopenia are not typical findings.

**Option C:** Infectious Mononucleosis - Infectious mononucleosis can cause fever, weakness, and splenomegaly, but the anemia and thrombocytopenia are not characteristic.

**Option D:** Autoimmune Hemolytic Anemia - Autoimmune hemolytic anemia can cause anemia, but the leukocytosis and thrombocytopenia are not typical findings.

**Clinical Pearl / High-Yield Fact**
The patient's presentation with fever, weakness, and splenomegaly should prompt an evaluation for a hematological disorder, including a complete blood count, reticulocyte count, and bone marrow biopsy if indicated.

**Correct Answer: A. Chronic Myeloid Leukemia (CML)**

✓ Correct Answer: A. Aplastic anemia