Lymph Node & Bone Marrow Cytology

Three causes of lymphadenopathy

Hyperplasia (reactive node), lymphoma, lymphadentitis

What is the normal tissue composition of lymph nodes?

Adult and immature lymphocytes predominate

Lymphoblasts <20% of all cells

Occasional plasma cells

Rare macrophages and neutrophils

Very rare eos and mast cells

What cells are seen in lymphoma?

>50% lymphoblasts (up to 100%)

Mitotic figures

Little to no presence of adult lymphocytes and plasma cells

What cells are seen in a reactive lymph node?

Predominately small lymphocytes,

Many plasma cells present (5-20%)

Lymphoblasts <20%

Rare macrophages and neutrophils

What cells are seen in lymphadenitis

Purulent exudate, increased neutrophils and macrophages (up to 100%)

May see increase in eosinophils with granulomatous lymphadenitis

How can you determine metastasis?

The presence of any cell type not normal to the lymph nodes

What components make up normal adult bone marrow?

Nucleated cells 50%

• WBC precursors 5%

• WBC adults 25%

• RBC precursors 2%

• RBC Adults 17%

• Megakaryocytes and platelets - 1%

Fat 50%

What cells can be seen in normal young bone marrow

Nucleated cells 90%

• WBC Precursors 9%

• WBC adults 45%

• RBC Precursors 4%

• RBC adults 30%

• Megakaryocytes and platelets 1%

Fat 10%

What cells can be seen in normal geriatric bone marrow?

Nucleated cells 30%

• WBC Precursors 3%

• WBC adults 15%

• RBC Precursors 1%

• RBC Adults 10%

• Megakaryocytes and platelets 1%

Fat 70%