Week 10 Part 1 - Lymph Node Cytopathology Flashcards
Goal of Lymph Node FNA
To make a positive diagnosis of specific benign lesions
To identify non-specific benign/reactive nodes which can be followed up without excision
To make a positive diagnosis of metastatic lesions
To make a positive specific lymphoma diagnosis
To identify probable/definite cases of lymphoma which require excision for confirmation/grading etc.
To obtain material for ancillary testing to guide therapy
Missed Goals of Lymph Node FNA
Insufficiently specific malignant diagnosis for management
Unable to make definite malignant diagnosis when management affected
- H&N SCC
- axillary lymph node for breast ca
Histology of Lymph Nodes
Function of the LN is to interact with antigens
Contact with antigens is constant, therefore most nodes show some degree of stimulation/activation
Four zones
1. Cortex - form precursors of AB forming cells and memory B cells
2. Paracortex - produces antigen-specific T cells and memory T cells
3. Medullary region - plasma cells reaction leads to formation of AB-secreting B cells
4. Sinuses - antigen processing
Types of Hyperplasia in Lymph Node During Stimulation
Follicular hyperplasia - primary/secondary follicles
Paracortical - dermatopathic, virus, drug, nodal reactions to malignancy
Sinusoidal - reaction to infection or malignancy, RDD, LCH, vascular transformation of sinuses
Medullary
Non-Specific Reactive Node - Clinical
Can be seen in any age, usually not elderly
Neck, axilla, groin are common sites
Usually <20mm, soft
May be an obvious infectious/inflammatory association
Often a waxing/waning history
Normal Nodal Aspirate
Usually highly cellular
Lymphoglandular bodies (rounded cytoplasmic fragments)
Predominantly small lymphocytes
Histiocytes
Dendritic cells
Tingible body macrophages
Plasma cells, mast cells, eosinophils, neutrophils
Reactive Germinal Centre
Centrocytes - variable size with inconspicuous nucleoli
Centroblasts - large with vesicular nuclei and multiple distinct nucleoli
Immunoblasts - very large, single nucleoli, basophilic cytoplasm
Dendritic reticulum cells - bean shaped, fine nuclear membranes
Tingible body macrophages
Granulomatous Lymphadenitis - Cytology
Syncytial aggregates of activated macrophages
- epithelioid histiocytes
- giant cells
Granulomatous Lymphadenitis Types
Necrotising (e.g. Mycobacterial, fungal)
Suppurative (e.g. Cat scratch, LGV)
Well formed non-necrotising (e.g. sarcoid)
Foreign material
Reaction to tumour
Toxoplasma (“semi-granulomas”)
Examples of Non-Infectious Granulomatous Disorders
Sarcoidosis lymphadenitis
Sarcoid-like lymphadenitis
Berylliosis
Examples of Suppurative Infectious Granulomatous Disorders
Tularemia lymphadenitis
Cat Scratch lymphadenitis
Yersinia lymphadenitis
Fungal Infection
Examples of Non-Suppurative Infectious Granulomatous Disorders
Tuberculous lymphadenitis
Atypical mycobacterial infection
BCG lymphadenitis
Toxoplasma lymphadenitis
Syphilis
Fungal infection (Cryptococcus, Histoplasma, coccidioidomycosis, Pneumocystis)
Tuberculosis
Classical appearance is (caseating) necrotising granulomatous inflammation
May see granulomas only, necrosis only or suppurative appearance
Mycobacteria Testing
“Negative images” (where mycobacteria seen on MGG as negative stained rods)
ZN for AFB on smear or cell block (50%)
Gold standard is mycobacterial culture
Immunological testing (QuantiFERON-TB Gold)
PCR (TB)
Cat-Scratch Disease
Caused by Bartonella Henselae
Typically affects cervical nodes in young people, but can involve any node
DDx includes LGV and other suppurative lymphadenitis
Cat-Scratch Disease Cytology
Suppurative granulomatous inflammation is the classical finding
Neutrophils and dispersed macrophages may be only finding
Sarcoidosis
Multisystem granulomatous disease called sarcoid nodules
Susceptible organs are; lungs and hilar lymph nodes (80%), eyes (50%), skin (20%) and other lymph nodes
Will appear very similar to Tuberculosis however Sarcoidosis has a very clean bg compared to TB
Toxoplasma
Infection by protozoan, Toxoplasma gondii
Most common clinical manifestation is lymphadenopathy
Typically involves posterior cervical lymph nodes
Toxoplasma Cytology
Follicular hyperplasia - polymorphs, TBMs, lymphohistiocytic aggregates
Prominent small clusters of histiocytic cells with round/ovoid nuclei
Toxoplasma Laboratory Findings
PCR positive
Toxo serology:
- IgG >300Iu/ML
- IgM positive
Suppurative Lymphadenitis
Typically bacterial infection
More common in children
Cytology is usual appearance of pus
EBV Lymphadenopathy
Usually cervical lymphadenopathy in adolescents/young adults
DDx - viral lymphadenitis, post vaccinal lymphadenitis and malignant lymphoma
EBV Lymphadenopathy Cytology
Cellular smears, with a follicular hyperplasia pattern/reactive lymph node of NS type
Prominent population of plasmacytoid cells and a florid population of immunoblasts with prominent nucleoli and atypical lymphoid cells
- n some cases cells with double nuclei may be seen and may mimic Reed Sternberg cells
EBV IHC
Some CD30 positive
CD15 negative
