Chronic Lymphocytic Leukemia (CLL)

What tissue is required to diagnose CLL?

Peripheral blood only — diagnosis is made by flow cytometry on circulating lymphocytes, not bone marrow.

What immunophenotype confirms CLL?

Clonal B‑cells expressing CD5(t cell marker), CD19, CD23, weak CD20, and light‑chain restriction (kappa or lambda only).

Why is bone marrow NOT required to diagnose CLL?

Because circulating neoplastic B‑cells are present in peripheral blood (and CLL cells are only cells in the body with +CD5, CD19, CD23) and flow cytometry is definitive. CLL is a B-Cell Malignancy

When should CLL treatment be initiated?

Only when symptoms outweigh chemo risks: symptomatic lymphadenopathy, symptomatic splenomegaly, or cytopenias caused by marrow infiltration (Rai stage III–IV).

Why is absolute lymphocyte count NOT an indication for CLL treatment?

Because lymphocytosis alone does not correlate with symptoms or prognosis.

What immune deficiency is common in Chronic Lymphocytic Leukemia (CLL)?

Hypogammaglobulinemia — low IgG causing recurrent or severe infections

What autoimmune cytopenia can CLL cause?

Autoimmune hemolytic anemia (AIHA) — diagnosed by ↑LDH, ↑bilirubin, ↓haptoglobin, and positive Coombs test.

What autoimmune platelet disorder can CLL cause?

Immune thrombocytopenia (ITP) — diagnosed when platelets are low but bone marrow shows normal or increased megakaryocytes.

How do you distinguish ITP from marrow infiltration in CLL?

Bone marrow biopsy: ITP shows normal/increased megakaryocytes

What is hairy cell leukemia?

A rare, slow‑growing B‑cell malignancy with CD19/20/22 positivity, aberrant CD103 expression, and TRAP positivity.

What is the classic peripheral blood morphology of hairy cell leukemia?

“Hairy cells” with cytoplasmic projections.

What is the classic bone marrow morphology of hairy cell leukemia?

“Fried egg” appearance with extensive fibrosis and dry tap on aspiration.