Bread loafing is a common method of processing surgical specimens for histopathology. The process involves cutting the specimen into 3 or more sections. [1] The cut sections are mounted by embedding in paraffin or frozen medium. The cut edge is then thinly sliced with a microtome or a cryostat. The thin slices are then mounted on a glass slide, stained, and covered with another layer of glass.
This method is used to determine the negative resection margin for skin tumors, and is also known as POMA (Post Operative Margin Assessment as referred to by the National Comprehensive Cancer Network). [2] It has a higher false negative error rate than the CCPDMA method of tissue processing. [3] The error rate is reduced when the surgical margin is increased, and the error rate is increased when the surgical margin is decreased. For this reason, it is not used near the eyelids, and in other cosmetically important areas of the body.
Bread loafing false negative error rate can be reduced by "cutting through the block". Basically, the entire surgical specimen is sliced, and mounted. Even though this method will approach CCPDMA, frequently, about 9 out of 10 sections are discarded. Thus, only 10% of the surgical margin is examined. If the whole "ribbon" was mounted, it would take an inordinate number of glass slides, and not be feasible.
Histology, also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures visible without a microscope. Although one may divide microscopic anatomy into organology, the study of organs, histology, the study of tissues, and cytology, the study of cells, modern usage places all of these topics under the field of histology. In medicine, histopathology is the branch of histology that includes the microscopic identification and study of diseased tissue. In the field of paleontology, the term paleohistology refers to the histology of fossil organisms.
Cytopathology is a branch of pathology that studies and diagnoses diseases on the cellular level. The discipline was founded by George Nicolas Papanicolaou in 1928. Cytopathology is generally used on samples of free cells or tissue fragments, in contrast to histopathology, which studies whole tissues. Cytopathology is frequently, less precisely, called "cytology", which means "the study of cells".
A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a disease. The tissue is then fixed, dehydrated, embedded, sectioned, stained and mounted before it is generally examined under a microscope by a pathologist; it may also be analyzed chemically. When an entire lump or suspicious area is removed, the procedure is called an excisional biopsy. An incisional biopsy or core biopsy samples a portion of the abnormal tissue without attempting to remove the entire lesion or tumor. When a sample of tissue or fluid is removed with a needle in such a way that cells are removed without preserving the histological architecture of the tissue cells, the procedure is called a needle aspiration biopsy. Biopsies are most commonly performed for insight into possible cancerous or inflammatory conditions.
A microscope slide is a thin flat piece of glass, typically 75 by 26 mm and about 1 mm thick, used to hold objects for examination under a microscope. Typically the object is mounted (secured) on the slide, and then both are inserted together in the microscope for viewing. This arrangement allows several slide-mounted objects to be quickly inserted and removed from the microscope, labeled, transported, and stored in appropriate slide cases or folders etc.
Basal-cell carcinoma (BCC), also known as basal-cell cancer, is the most common type of skin cancer. It often appears as a painless raised area of skin, which may be shiny with small blood vessels running over it. It may also present as a raised area with ulceration. Basal-cell cancer grows slowly and can damage the tissue around it, but it is unlikely to spread to distant areas or result in death.
Histopathology refers to the microscopic examination of tissue in order to study the manifestations of disease. Specifically, in clinical medicine, histopathology refers to the examination of a biopsy or surgical specimen by a pathologist, after the specimen has been processed and histological sections have been placed onto glass slides. In contrast, cytopathology examines free cells or tissue micro-fragments.
A cryostat is a device used to maintain low cryogenic temperatures of samples or devices mounted within the cryostat. Low temperatures may be maintained within a cryostat by using various refrigeration methods, most commonly using cryogenic fluid bath such as liquid helium. Hence it is usually assembled into a vessel, similar in construction to a vacuum flask or Dewar. Cryostats have numerous applications within science, engineering, and medicine.
A microtome is a cutting tool used to produce extremely thin slices of material known as sections. Important in science, microtomes are used in microscopy, allowing for the preparation of samples for observation under transmitted light or electron radiation.
Lentigo maligna is where melanocyte cells have become malignant and grow continuously along the stratum basale of the skin, but have not invaded below the epidermis. Lentigo maligna is not the same as lentigo maligna melanoma, as detailed below. It typically progresses very slowly and can remain in a non-invasive form for years.
The frozen section procedure is a pathological laboratory procedure to perform rapid microscopic analysis of a specimen. It is used most often in oncological surgery. The technical name for this procedure is cryosection. The microtome device that cold cuts thin blocks of frozen tissue is called a cryotome.
Mohs surgery, developed in 1938 by a general surgeon, Frederic E. Mohs, is microscopically controlled surgery used to treat both common and rare types of skin cancer. During the surgery, after each removal of tissue and while the patient waits, the tissue is examined for cancer cells. That examination dictates the decision for additional tissue removal. Mohs surgery is the gold standard method for obtaining complete margin control during removal of a skin cancer using frozen section histology. CCPDMA or Mohs surgery allows for the removal of a skin cancer with very narrow surgical margin and a high cure rate.
Surgical pathology is the most significant and time-consuming area of practice for most anatomical pathologists. Surgical pathology involves gross and microscopic examination of surgical specimens, as well as biopsies submitted by surgeons and non-surgeons such as general internists, medical subspecialists, dermatologists, and interventional radiologists.
Gross processing or "grossing" is the process by which pathology specimens undergo examination with the bare eye to obtain diagnostic information, as well as cutting and tissue sampling in order to prepare material for subsequent microscopic examination.
A resection margin or surgical margin is the margin of apparently non-tumorous tissue around a tumor that has been surgically removed, called "resected", in surgical oncology. The resection is an attempt to remove a cancer tumor so that no portion of the malignant growth extends past the edges or margin of the removed tumor and surrounding tissue. These are retained after the surgery and examined microscopically by a pathologist to see if the margin is indeed free from tumor cells. If cancerous cells are found at the edges the operation is much less likely to achieve the desired results. Residual tumour at the primary site after treatment is classified by the pathologist as :
Skin biopsy is a biopsy technique in which a skin lesion is removed to be sent to a pathologist to render a microscopic diagnosis. It is usually done under local anesthetic in a physician's office, and results are often available in 4 to 10 days. It is commonly performed by dermatologists. Skin biopsies are also done by family physicians, internists, surgeons, and other specialties. However, performed incorrectly, and without appropriate clinical information, a pathologist's interpretation of a skin biopsy can be severely limited, and therefore doctors and patients may forgo traditional biopsy techniques and instead choose Mohs surgery. There are four main types of skin biopsies: shave biopsy, punch biopsy, excisional biopsy, and incisional biopsy. The choice of the different skin biopsies is dependent on the suspected diagnosis of the skin lesion. Like most biopsies, patient consent and anesthesia are prerequisites.
Automated tissue image analysis or histopathology image analysis (HIMA) is a process by which computer-controlled automatic test equipment is used to evaluate tissue samples, using computations to derive quantitative measurements from an image to avoid subjective errors.
Complete circumferential peripheral and deep margin assessment (CCPDMA) is the preferred method for the removal of certain cancers, especially skin cancers.
Electrodesiccation and curettage is a medical procedure commonly performed by dermatologists, surgeons and general practitioners for the treatment of basal cell cancers and squamous cell cancers of the skin. It provides desiccation, coagulation/cauterization, and curettage to remove lesions from the skin.
A breast biopsy is usually done after a suspicious lesion is discovered on either mammography or ultrasound to get tissue for pathological diagnosis. Several methods for a breast biopsy now exist. The most appropriate method of biopsy for a patient depends upon a variety of factors, including the size, location, appearance and characteristics of the abnormality. The different types of breast biopsies include fine-needle aspiration (FNA), vacuum-assisted biopsy, core needle biopsy, and surgical excision biopsy. Breast biopsies can be done under ultrasound, MRI or a stereotactic biopsy technique. Vacuum assisted biopsies are typically done using stereotactic techniques when the suspicious lesion can only be seen on mammography. On average, 5-10 biopsies of a suspicious breast lesion will lead to the diagnosis of one case of breast cancer.
Microtechnique is an aggregate of methods used to prepare micro-objects for studying. It is currently being employed in many fields in life science. Two well-known branches of microtechnique are botanical (plant) microtechnique and zoological (animal) microtechnique.