Tumor Biopsy and Specimen Submission

Chapter 70

Tumor Biopsy and Specimen Submission

Tumor biopsy specimens typically are submitted to obtain a diagnosis. This diagnosis, in conjunction with additional information in the pathology report, becomes the cornerstone on which therapeutic decisions and management of the patient are based. The information provided in the pathology report should be accurate, thorough, and reliable. Generation of such a report, in turn, relies upon the submission of quality specimens and necessary clinical information by the clinician requesting specimen analysis.

Tumor Biopsy and Tissue Procurement

Several biopsy techniques are available and the decision to use one over the others depends on specific details of the individual tumor and patient. These techniques, including incisional (needle-core, punch, wedge) and excisional biopsy, are addressed in Web Chapter 32. Specimens obtained endoscopically and via flushes or washes (e.g., nasal flush, traumatic catheterization) are also included.

Regardless of the technique employed, universal principles apply regarding tissue acquisition and handling. The fundamental purpose of a biopsy is to obtain a reliable diagnosis. This depends, at least in part, upon submission of quality diagnostic specimens. Acquiring viable tissue from representative regions and minimizing tissue artifact from time of acquisition to delivery at the laboratory help to ensure submission of a diagnostic sample.

Obtaining a Diagnostic Sample

Principles to follow to increase the potential for obtaining a viable and representative sample by incisional biopsy include the following (Box 70-1):

• Biopsy both mass and surrounding normal tissue—the tumor-nontumor junction. This region provides the highest diagnostic yield and in addition may provide information on invasion.

• Avoid obtaining tissue solely from the center of the mass. The center typically is the most necrotic, which often results in a nondiagnostic sample.

• Obtain ample tissue or, if possible, multiple samples from different areas. This increases the chance of obtaining a representative section.

• Biopsy an alternative area of the mass if the first specimen has the following characteristics:

Minimizing Tissue Artifact: Handling and Fixation

Regardless of biopsy technique, minimizing tissue artifact during and after the procedure is critical. Principles to follow include the following (Box 70-2):

• Avoid excessive tissue trauma. For example, be aware of the negative effect of suction on biopsy quality, avoid crush artifact by gentle handling with forceps, and minimize the degree of palpation before biopsy or physical handling of the specimen afterward.

• Electrocautery or lasers should be not be used to cut the tissue because these compromise tissue architecture, which hinders evaluation of margins and excisional completeness. After excision with a scalpel blade, electrocautery can be used for hemostasis as long as no tissue from the tumor bed will be collected.

• Ensure proper fixation to preserve tissue architecture.

• Avoid tissue freezing. Freezing causes ex vivo ice crystal formation, cell shrinkage, and lysis leading to extensive tissue artifact, which markedly compromises microscopic evaluation.

Sample Submission

Tissue specimens range from endoscopic biopsy samples to entire spleens and amputated limbs. There is no one way to handle all specimens, although the principles listed earlier universally apply. This section addresses methods of handling some unconventional biopsy specimens. Methods and principles of tissue marking (e.g., identifying surgical margins) as well as the benefits of providing thorough information on the submission form also are addressed. Further information on these topics is available in a recent consensus document (Kamstock et al, 2011), which readers are encouraged to review.

Fixation and Packaging

The most widely used fixative is 10% neutral buffered formalin. Others, such as Davidson’s and Bouin’s solutions, also are available and may be preferable for certain tissues (e.g., eyes, testes, brain). More recently, a number of low-hazard, formalin-free fixatives (e.g., ExCell Plus, FineFIX, RCL2), which also better preserve the tissue for molecular testing, are gaining interest. Many laboratories provide prefilled containers. The following principles apply to containers:

• The container should be a wide-mouthed plastic jar with a lid that seals securely.

• If the jar has a narrow neck, the neck must be wider than the specimen being submitted. Fresh tissue is malleable and can be squeezed through the neck easily; however, fixed tissue becomes rigid and will be impossible to retrieve without damage.

• The container (not lid) should be labeled with the patient’s name, case number, and anatomic site from which the specimen was obtained (e.g., dermal mass, thorax). If multiple specimens are submitted in one jar, a numbered list of the specimens and respective anatomic sites should be provided and the specimens themselves should be identified so that they correlate with the list.

• The container should be placed in one, if not two, secured and sealed plastic bags to contain any leakage during shipping and should be surrounded by absorbent packing material.

• Glass should be avoided because it carries a greater risk of breaking in transit.

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Jul 18, 2016 | Posted by in PHARMACOLOGY, TOXICOLOGY & THERAPEUTICS | Comments Off on Tumor Biopsy and Specimen Submission

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