Fine Needle Biopsy
Fine Needle Biopsy (FNB) is obtaining histological evidence of cancer through tissue or fluid to diagnose and stage the extent of GI diseases. The goal of FNB is to obtain evidence of cancer through core tissue samples, allowing for a more representative sample of the suspect lesion. Core biopsies may allow for additional testing or stains needed to verify specific, hard to diagnose disease states.
Although the diagnostic yield of EUS-FNA for pancreatic masses remains high, it continues to be suboptimal for non-pancreatic lesions. Technical limitations include availability of cytologic expertise, scant cellularity of specimens and inability to demonstrate lesion morphology and architecture. Histologic specimens or core biopsies may:
- improve assessment of tissue architecture,
- provide a more representative sample of the lesion,
- allow for immunohistochemistry or vital stains and
- potentially eliminate the need for OCE (On-site Cytopathology Evaluation), resulting in significant cost savings.
Specimen Handling of FNB
Specimen handling of FNB is critical. The appropriate handling of a core specimen is essential to ensure optimal diagnostic yield. If OCE (On-site Cytological Evaluation) is NOT used in the room, the specimen should be expelled with air, stylet or water flush directly into 10% formalin.
If the tissue acquired is a visible core, standard touch preparation is used. The core is slowly and carefully touched to the slide and then placed into a specimen container with formalin, as seen in the first photo.
In the event that only fragmented or scant tissue is obtained, the tissue is placed on a slide and a second slide should be used to gently crush the tissue and prepare an air-dried crush preparation. Any residual tissue should be fixed in 10% formalin for subsequent hematoxylin and eosin staining.
