Introduction

Lymph nodes were probably the first organs to be investigated by fine needle cytology (FNC) and the last in which this technique has been accepted by clinicians as a useful diagnostic procedure. Risk of seeding, false negatives, failure to discriminate between reactive hyperplasia and lymphoma, have been put forward as a limitation or useless of FNC. Nonetheless, as this technique is fast, inexpensive and effective, it is often required by general practitioners, specialists and surgeons as first diagnostic approach to lymph nodes; moreover, ancillary techniques such as immuocytochemistry, flow cytometry, fluorescence in situ hybridization and molecular techniques are successfully employed on cytological samples, conferring to FNC of lymph nodes credibility and a definite role in the diagnosis of lymphadenopaties. There are exhaustive books and excellent articles providing lymph nodal cytopathologists with the necessary knowledge of the different pathologies encountered, and the limitations of the technique; however, a small dose of audacity is also a useful complement when practicing this field of cytology.

Preliminary suggestions

• Perform FNC of lymph nodes by yourself: clinical evaluation, correct FNC, management of the diagnostic material, perfect smears and their immediate evaluation are very important for a correct diagnosis.
• Distrust smears prepared by others and do not try to diagnose on sub-optimal or technically poor smears.
• Evaluate preliminary clinical, serological, and imaging data but leave your mind open: the microscope can disprove any reasonable diagnostic hypothesis .
• Use ancillary techniques on the basis of the cytological features and clinical indications.
• Do not delay, if possible, essential information to the clinicians (benign-malignant), awaiting further microscopic evaluation, results from special techniques or bibliographic researches.
• Draw up your diagnosis in an regular and consequential manner, reporting, if possible:
  1. the anatomical identification of the target (i.e. a lymph node)
  2. the diagnostic category: negative, positive, suspicious, inadequate
  3. a brief and pertinent cytological description
  4. the final diagnosis, considering what may be asserted, what may only be assumed and what cannot be maintained or excluded.