Comparative analysis on efficacy of lymph node sampling through whole node excision versus core needle biopsy: focusing on diagnostic yield for interpretation

The interpretation of lymph node biopsy is influenced by factors inherent to the type of biopsy. In recent times, core needle biopsies (CNB) have increasingly been preferred over whole node excision (WNE) for sampling lymph nodes.

To compare the diagnostic efficacy of CNB and WNE in diagnosing lymph node pathologies and to evaluate the diagnostic challenges in interpreting CNB.

Lymph node biopsies (CNB and WNE) received over 5.5 years were analyzed using hematoxylin and eosin (H&E) stain and immunohistochemistry (IHC). The percentage of cases diagnosed on morphology alone and with IHC in each group was evaluated. Cases that did not have a definitive diagnosis, even after the application of IHC, were analyzed.

A total of 751 lymph node biopsies were studied, comprising 222 CNB and 529 WNE. Based on morphology alone (± special stains), the diagnosis could be established in 63/222 (28.4%) cases on CNB and 308/529 (58.2%) of WNE. After IHC, a diagnosis could be rendered in 65.8% of CNB, compared to 95.8% of WNE. Thus, 17.6% of CNB remained inconclusive even after IHC, and 16.7% of CNB had inadequate or nonrepresentative tissue. CNB was more prone to fragmentation, cellular distortion, crushing, and shrinkage, thereby challenging the interpretation.

WNE offers a significantly higher diagnostic yield and provides complete nodal architecture and fewer tissue artefacts, making it a superior sampling technique to CNB for diagnosing lymph node lesions. Inconclusive diagnoses on CNB are due to a lack of architectural pattern, limited tissue, nonrepresentative sampling, and procedural artefacts.