part 5 - lymp nodes

Preferred sampling method OF LYMPH NODES

Needle-only (no suction)

Reason for avoiding suction OF LYMPH NODES

Prevent rupture of fragile lymphoid cell

Why is FNA of normal lymph nodes rarely done

Because knowing normal cytology mainly helps interpret abnormal findings

What is the predominant cell type in normal lymph nodes

Small lymphocytes (>90%), small round cells with thin rim of basophilic cytoplasm and dense nucleus (size ≈ RBC)

What proportion of intermediate to large lymphocytes are found in normal lymph nodes

Less than 10%

Describe intermediate to large lymphocytes

Larger cells with more cytoplasm, coarse chromatin, and up to 3 nucleoli

Which other cells are occasionally seen in normal lymph nodes

Few macrophages and plasma cells

What is lymphoid hyperplasia

Benign and reversible enlargement of lymphoid tissue secondary to antigenic stimulation

Can lymphoid hyperplasia affect a single lymph node

Yes, usually in response to localized inflammation

Where is localized lymphoid hyperplasia commonly observed in dogs and cats

In submandibular lymph nodes with periodontal disorders

When does generalized lymphoid hyperplasia occur

Secondary to systemic antigenic stimulation

Which conditions are associated with generalized lymphoid hyperplasia

FeLV, FIV, FIP, bartonellosis, and chronic ehrlichiosis

What does cytology of reactive lymph nodes show

Heterogeneous mix of lymphoid cells at various maturation stages, mainly small lymphocytes with fewer intermediate and large forms

Which additional cells may be seen in reactive lymph nodes

Variable numbers of plasma cells, Mott cells with Russell bodies, rare macrophages, eosinophils, and mast cells

Why can reactive hyperplasia be difficult to differentiate from early lymphoma

Both can show mixed lymphoid populations; histopathology may be required to confirm diagnosis