How to assess if a patient with lymph node enlargement requires fine needle aspiration
(Aotea News, December 2009)
In community pathology practice, most requests for fine needle aspiration (FNA) consultations are for patients with lymphadenopathy. Evidence-based good practice assessments now question what role, if any, FNA has in their work-up.
Below are some guidelines to help you assess if a patient should be referred for FNA.
There are three clinical scenarios to consider.
Patients with a previous diagnosis of malignancy (usually head and neck cancers, breast cancer or malignant melanoma) who present with lymphadenopathy and the clinical questions is, “Does this adenopathy represent metastatic disease?”
In these situations, FNA of the node or nodes is a quick, cheap and highly sensitive test that can usually replace an open lymph node biopsy.
The two other scenarios are less straightforward.
Patients with a strong clinical suspicion of malignant lymphoma, either Hodgkin’s disease (HD) or non-Hodgkin’s lymphoma (NHL).
These are usually patients with very significant painless lymph node enlargement (usually greater than 20mm) often in groups of nodes. Constitutional symptoms (fever, night sweats, weight loss etc) may or may not be present and there may be no inciting causes for their adenopathy.
FNA of these patients, especially in combination with ancillary testing, as discussed below can lead to diagnosis of “atypical lymphoid population suspicious / highly suspicious for lymphoma”.
However, the FNA diagnosis does not significantly benefit these patients for the following reasons:
- The FNA was instigated because of a strong suspicion of lymphoma anyway.
- HD and NHL represent a very heterogeneous group of malignancies with considerably different treatment and prognosis across the spectrum. Accurate subtyping and hence treatment depends on special studies usually conducted on fresh lymph node tissue, not on FNA material.
- FNA assessment may lead to delays in obtaining fresh lymph node tissue or, more seriously, may make subsequent examination of fresh tissue impossible due to the risk of nodal infarction.
- FNA has a very poor sensitivity for the diagnosis of low grade NHL and most subtypes of HD.
The recommendation for this scenario is that, with a clinical suspicion of lymphoma, referral for formal lymph node biopsy is preferred to FNA in the initial workup.
The third scenario is patients with minor degrees of lymphadenopathy usually less then 15mm in size and where referral for FNA is simply a reflex action.
These patients are often concerned on discovering physiological shotty nodes in the neck or groin region or single occipital or jugulodigastric nodes. Alternatively there may be adenopathy at multiple sites with a clinical history suggestive of viral infection such as EBV.
Because of the sensitivity issues surrounding FNA and lymphoma diagnosis, morphologic assessment is usually combined with sophisticated, and therefore expensive, flow cytometric examination of cell suspension samples to improve accuracy. The combined cost to the funder or patient can often exceed $500 which seems hard to justify on clinical grounds.
It is recommended that practitioners are cautious in referring these patients for early FNA.
- carefully excluding potential causes for the lymphadenopathy through clinical examination and the use of viral (EBV, CMV) and toxoplasma serology.
- reassurance of the patient that shotty and small nodes are normally physiological or reactive and do not, in the first instance, require complex investigations.
- that most physiological and reactive lymphadenopathy will show evidence of subsiding over a 6 to 12 week period and that watchful waiting can be a powerful approach.
- However, adenopathy that persists or progresses after a three month follow-up is certainly worthy of consideration for FNA.
Talk to us for case-by-case information
Aotea Pathology regularly receives clinically inappropriate requests for FNA examination of enlarged lymph nodes. In such situations the pathologists will often send the patient away after examination without performing the FNA procedure.
We hope these guidelines are of use in assessing when to refer for FNA, and please remember that Aotea Pathology cytopathologists are very happy to discuss individual cases with referrers. Feel free to call Drs Bethwaite, McCafferty or Wood with any questions or concerns.