FNA vs. FNB
Pathologists look at tissue samples two different ways: FNA or FNB. FNA shows tissue samples at the cellular level, with slides prepared in Cytolyt. When using FNB, the sample is that of an intact core sample, revealing the true architecture of the tissue, which is preserved in Formalin. FNB does not improve the diagnostic yield of malignancy compared with FNA. However, the ability to obtain histologic specimens can aid in diagnosing benign conditions such as autoimmune or chronic pancreatitis, in which the assessment of tissue architecture is necessary to achieve a diagnosis. In addition, EUS-FNB should be considered in lesions with prior non-diagnostic EUS.
Compare the slides showing the differences between FNA and FNB from a pathologist’s perspective. The sample came from a 65-year-old man with a pancreatic mass in the head of the pancreas with EUS. EUS showed a well-defined round-shaped and slightly hypoechoic solid tumor in the uncinate. An FNB of the lesion was performed with a 25-gauge core biopsy needle.
| FNA-cellular level; cytological analysis |
FNB-architecture of cells; histological analysis |
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- The specimen was expelled onto a glass slide. Macroscopic evaluation showed visible core, measuring 40 mm in length.
- The macroscopic visible core was picked up and placed into a formalin bottle for histologic analysis.
The remaining specimen was submitted for cytologic analysis. Cytologic and histologic findings showed neuroendocrine tumor.
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