What is the difference between fine needle aspiration and core biopsy?
Percutaneous needle biopsy includes two basic techniques for obtaining tissue samples: FNA and core biopsy.
FNA refers to sampling using thin hollow needles (20 gauge [G] and smaller) that extract loose cells for cytologic evaluation.
Core biopsy refers to the use of hollow needles (20 G and larger) with a cutting mechanism that extracts a thin cylinder of tissue, usually 1 to 2 cm long, for histologic evaluation.
The size of the needle and the use of aspiration or core biopsy depend on the target organ and the type of lesion that requires sampling. Most cancers can be diagnosed by cytologic analysis, but certain lesions require assessment of histopathologic architecture of tissue for diagnosis.
In most cases, needle aspirations are adequate for differentiating benign from malignant disease and can serve to stage patients with cancer.
However, the majority of patients do not undergo surgical resection, and specimens obtained for therapeutic planning purposes should allow for extended diagnoses, including the determination of biomarker profiles.
In the current era of personalized medicine and targeted chemotherapies, molecular studies of biopsy samples is increasingly necessary, and evaluation for these markers often requires core biopsy specimens.
Both types of biopsies can be performed during a single procedure, if needed, thus obtaining both cytologic and histologic specimens.
Which type of biopsy to perform is determined by the type of tumor suspected, the size and location of the lesion, and what information is necessary for treatment planning.
Because of the limited tissue retrieved with FNA, core biopsy has evolved as an alternative, using a 10- to 14-gauge coring needle to obtain cylindrical tissue blocks.
A block of tissue allows the pathologist to examine tumor architecture and cellular interrelation, improving the diagnosis of histologic subtype and grade compared to FNA.
Fine needle aspiration (FNA) and core biopsy are two different techniques used to obtain tissue samples from suspicious or abnormal areas in the body for diagnostic purposes. They are both minimally invasive procedures commonly performed to evaluate lumps, masses, or lesions found on imaging studies. Here are the key differences between FNA and core biopsy:
- Fine Needle Aspiration (FNA):
- Procedure: In FNA, a thin and fine needle is inserted into the suspicious area, typically guided by ultrasound, CT scan, or other imaging modalities. The needle is used to aspirate (suck out) a small sample of cells or fluid from the area of interest.
- Sample Size: FNA usually yields a small sample of individual cells or clusters of cells. The sample is then smeared on a glass slide for examination under a microscope by a pathologist.
- Applications: FNA is commonly used to investigate cysts, superficial masses, or to collect cells from organs or tissues that can shed cells easily (e.g., thyroid, lymph nodes).
- Core Biopsy:
- Procedure: Core biopsy involves the use of a larger, hollow needle that allows the extraction of a cylindrical or “core” tissue sample from the abnormal area. The procedure is also typically guided by ultrasound, CT, or other imaging modalities.
- Sample Size: Core biopsy provides a larger tissue sample compared to FNA. The sample contains intact tissue architecture and can be processed as a solid specimen for examination by a pathologist.
- Applications: Core biopsy is particularly useful when a more substantial tissue sample is needed for accurate diagnosis, especially in cases where FNA might not provide enough information. It is commonly used to assess solid masses, tumors, or lesions in organs like the breast, liver, kidney, or prostate.
In summary, FNA is a technique to obtain individual or clustered cells, while core biopsy involves the extraction of a larger, intact tissue sample. Both procedures have their specific applications, and the choice between FNA and core biopsy depends on factors such as the suspected diagnosis, the location of the abnormality, and the type of tissue or organ being evaluated. The decision on which method to use is often made by the treating physician or radiologist based on the specific clinical scenario.
