Biopsy Specimens: Collection and Types Explained
Biopsy specimens are samples of tissue or cells collected from the body for microscopic examination. They play a crucial role in diagnosing various medical conditions, particularly cancer. Biopsy specimens are essential tools in medical diagnosis and research, as they provide insights into the cellular and structural characteristics of tissues and organs. These specimens are collected through various methods, each tailored to the location and nature of the suspected abnormalities.
Surgical specimens after removal should be placed in an adequate quantity of fixative (10% formal saline) as soon as possible. For optimal fixation a piece of tissue should be immersed in at least 10 times its own volume of fixative.
Jars or bottles with screw tops and of suitable capacity should be used. Large specimens should not be squeezed into a smaller container. This will result in inadequate fixation and will allow autolysis to proceed unchecked. The subsequent interpretation of microscopic appearances may thus be made difficult or impossible. If a specimen is too large to fit easily into the largest size of container it should be brought as such to the laboratory without delay in a bucket or other suitable container. Amputated limbs may be wrapped in a rubber sheet. Bulky solid specimens, e.g., large tumours, spleen, etc. should be bisected cleanly with a large sharp knife before being placed in fixative. Hollow viscera such as portions of stomach and intestine should be opened at both ends or cut open along their length (stomach should be opened along the greater curvature). If, for any reason, jars of fixative are not available, the specimen should be taken fresh to the laboratory or wrapped in moist cotton wool and put in the refrigerator overnight. The specimen should never be put into water or normal saline because this will hasten autolysis.
Rapid Frozen Section:
If a rapid frozen section is required the laboratory staff and pathologist must be notified at least 1 hour before the time of the operation and preferably on the preceding day. Arrangements should also be made to notify the laboratory as soon as the patient is taken into the theatre for the start of the operation. The specimen must not be put into a fixative but be brought with the least possible delay to the laboratory. If after the start of the operation, the surgeon decides that a rapid frozen section is unnecessary the laboratory should be notified at once.
If more than one biopsy is taken from the same patient at the same time, a single request form will suffice for all those specimens relating to a single pathological lesion. If two or more apparently unrelated pathological lesions are biopsied from the same patient, separate forms should accompany each specimen. If previous specimens from the same patient have been sent to the laboratory, this fact should be stated on the form together with the approximate date of previous histological examination. If this was done in another laboratory, this fact should also be clearly stated. The medical officer in charge of the case must complete the forms. Apart from the usual particulars required on any request form the clinical data must include any specific information contributing or relating to the present illness. In surgical cases the following additional information is required:
- Precise nature of the operation performed.
- Whether the entire specimen or only a part of it is being sent to the laboratory.
Labelling of Specimen:
It is the responsibility of the Medical Officer to see that the specimens are correctly labelled, including the name of the patient, ward, hospital and specimen; with date and time of obtaining the specimen. These particulars should tally with those stated in the accompanying request form.
1. Renal Biopsy:
The specimen of renal biopsy for histopathological examination should be collected in 10% formal saline. The request form should contain all the relevant clinical information and results of laboratory investigations. The specimen of renal biopsy for immunofluorescence should be submitted fresh in normal saline.
2. Liver Biopsy:
The liver biopsy specimen should be collected in 10% formalin/formal saline. Request form should mention the reports of LFTs and hepatitis markers tested besides the relevant clinical information. Liver biopsy specimen for the diagnosis of storage disorders should be collected in absolute alcohol.
3. Bone Specimen:
Bone specimen should be collected in 10% formal saline. Information regarding age, sex of the patient, site of biopsy, clinical history and x-ray with radiologists opinion are required for reporting on bone specimens and should accompany the specimen.
4. Endoscopic Biopsy:
Endoscopic biopsy procedures are carried out during endoscopy. An endoscope is a flexible tube with a camera that is inserted into the body to visualize and access the area of concern. This type of biopsy is commonly used for diagnosing gastrointestinal conditions, respiratory abnormalities, and urinary tract disorders.
5. Bone Marrow Biopsy:
A bone marrow biopsy involves the collection of a small sample of bone marrow from the hipbone (usually the iliac crest). It is crucial for diagnosing blood disorders, leukemia, and assessing the production of blood cells.
6. Punch Biopsy:
A punch biopsy uses a circular blade to remove a small, cylindrical sample of skin or mucous membrane tissue. It is often employed for diagnosing skin conditions, such as dermatitis, psoriasis, or skin cancers.
7. Needle Biopsy:
Fine-Needle Aspiration (FNA):
This minimally invasive technique uses a thin, fine needle to extract cells or a small amount of tissue from a suspicious lump or nodule. FNA is commonly used for diagnosing thyroid nodules, breast lumps, and lymph nodes.
Core Needle Biopsy:
It involves a larger, hollow needle to extract a core of tissue for more extensive examination. It is particularly useful for diagnosing breast, lung, and prostate cancers.
This method uses a vacuum to collect multiple samples of tissue through a single insertion of the needle. It provides a larger and more accurate sample for examination.
8. Brush Biopsy:
Brush biopsies use a small brush to collect surface cells from the mucous membranes, particularly in the cervix and esophagus. They are useful in diagnosing cervical abnormalities and esophageal conditions.
9. Lymph Node Biopsy:
Lymph node biopsies involve the removal and examination of lymph nodes. They help diagnose conditions like lymphoma, infections, and metastatic cancer.
10. Ultrasound-Guided Biopsy:
This technique utilizes real-time ultrasound imaging to guide the biopsy needle to the precise location of the abnormal tissue or lesion. It is commonly used for detecting abnormalities in various organs, including the liver, kidneys, and breast.
11. Surgical Biopsy:
This involves the removal of a part of the suspicious tissue or organ for examination. It is typically performed when taking the entire tissue is not necessary or feasible.
In contrast, an excisional biopsy removes the entire abnormal tissue or lesion. It is often done when the size and nature of the lesion allow for complete removal.
Biopsy specimens are processed and analyzed by pathologists to determine the nature of abnormalities, identify diseases, and guide treatment decisions. The choice of biopsy method depends on the suspected condition, the location of the abnormal tissue, and the patient’s overall health. Accurate diagnosis through biopsy specimens is crucial for effective medical care and treatment planning.