Histopathology Laboratory Services
...our specialist scientific and technical services
- Electron Microscopy
- Muscle biopsies
- Nerve biopsies
- Mohs Micrographic Surgery
- Research support
Immunocytochemistry (ICC) is a specialised section of histopathology and the technique involves the identification of specific targets (antigens) within cells and tissues. This involves the use of antibodies that are directed towards the specific targets of interest. The resulting antigen/antibody reaction is then visualised by tagging with a permanent label (chromogen). The presence of the antigen of interest can then be seen by microscopy.
Substances that can be identified by these techniques include micro-organisms, hormones, specific cell types, cellular components, enzymes and tumour markers.
These techniques allow a much greater range of targets to be identified in tissue sections and are of great value in the classification and understanding of disease processes. Examples of the diagnostic applications include the classification of lymphomas, prostatic cancers, skin cancers, hormone status of breast cancers and identification of soft tissue tumours. There is an increasing reliance on ICC as a diagnostic tool which has required a high degree of automation of techniques.
The application of antibodies labelled with a fluorescent tag is a procedure that is performed on fresh frozen skin, oral and renal biopsies. This specialist technique allows for the visualisation of immunoglobulins and complement fractions within the tissues. This technique must be carried out on fresh frozen biopsies because routine fixation affects their demonstration in paraffin sections. The fluorescence is then visualised using a microscope with an ultra-violet light source.
Another technique that is performed on fresh frozen biopsies is the acetylcholine esterase technique. This uses enzyme histochemistry to demonstrate the presence of ganglion cells in rectal biopsies and is employed in the diagnosis of Hirschsprungs disease.
In-situ hybridisation is also performed in the ICC section. This allows the detection of specific RNA sequences within a cell by using specific oligonucleotide probes. Probes currently in use are those for Epstein Barr virus, kappa and lambda light chains, HPV and Her2 gene.
Specimens of skin requiring immunofluorescence (IMF) should be sent to the laboratory in Michel’s medium supplied by the laboratory (contact 0191 282 4270 for supplies).
- Specimens sent in formalin are NOT suitable for IMF studies.
- If there is sufficient specimen it can be bi-sected, one fixed in formalin and one in Michel’s medium.
- Specimens for IMF should be sent to the laboratory immediately.
- Requests for reports on specimens from patients known to have, or suspected of having Transmissible Spongiform Encephalopathy (TSE),Tuberculosis (TB), Human Immunodeficiency Virus (HIV), hepatitis infection, Viral Haemorrhagic Fever (VHF) or any other category 3 or 4 pathogen must be clearly labelled as such and sent fixed and double bagged, marked with a biohazard label on both the request form and specimen container.
Transmission electron microscopy may aid in the diagnosis of routine surgical cases. In addition, as a University teaching hospital, research projects are undertaken and many cases are received as referrals.
The ability to resolve ultrastructure contributes in determining the histogenesis of tumours, especially those poorly differentiated tumours in which light microscopical markers are lacking. Seventy five per cent of cases are renal biopsies where visualisation of specific ultrastructural features is often of prognostic value.
Preparation of material is highly skilled requiring dexterity and patience to produce quality ultrasections (100-120nm). The interpretation of digital images is a collaborative effort between the scientific and medical staff.
A specialist area within the Department of Cellular Pathology, it is involved in the histopathological diagnosis of diseases of the central and peripheral nervous system. The service supports the work of the Neurology, Neuro-oncology and Neurosurgery departments within the NUTH Trust, as well as providing a regional specialist referral service. Both surgical and autopsy tissue samples are examined using the extensive resources of the Department.
The standard Histopathology Request Form (Form no. NUTH153) must be completed. Complete patient identification information is essential and full clinical details are also required (refer to Trust Sample Acceptance policy). In addition, details should be given of any previous biopsies with report numbers where available: previous reports should be found in the patient’s case notes. Please ensure that the Ward number, name of referring Consultant and a contact number are included on the request form.
Request forms with specimens from patients known to have, or suspected of having CJD, TB, AIDS, hepatitis B or C or other high-risk infection should identify the biohazard in the section on clinical details. Both request form and specimen container must be marked with a biohazard label. Note that as the processing of CJD material requires special techniques, reports from these cases may take substantially longer than average.
Neuropathology Frozen Sections
Requests for frozen sections should be telephoned to the laboratory, giving at least 30 minutes notice. If the specimen is likely to arrive in the laboratory after 17:00, you must inform the laboratory 0191 282 1482 before 16:00.
To ensure that the quality of a muscle biopsy sample is optimal for diagnostic evaluation, it should be handled like a specimen for intra-operative diagnostic evaluation. Thus, the sample has to be sent fresh NOT in formalin or other fluid), covered with a damp gauze, in a universal container immediately after the biopsy procedure to the Cellular Pathology Histopathology reception and the request form should be labelled as “urgent, fresh muscle sample!” Size of the muscle sample should be approximately 5mm x 5mm x 5mm.
The Cellular Pathology reception is located at the New Victoria Wing, Level 3. Preferably the Muscle and Nerve laboratory should be contacted (extension: 24270, or from outside the Trust: 0191-282 4270) at the time when the muscle sample is leaving the operation room, so that there is at least a few minutes warning. The fresh muscle sample will be orientated and snap frozen as soon as it is in the laboratory.
On the day of the Nerve Biopsy the Operating Theatre Staff needs to give a warning to the Muscle & Nerve Biopsy Service Staff at Cellular Pathology, RVI 0191 282 4270 to ensure they arrive in the theatre in time for the nerve biopsy
15 minutes warning is needed for RVI Operating Theatres
Mohs Micrographic Surgery is a highly successful treatment for skin cancer. The Royal Victoria Infirmary is currently the only hospital in the North East which offers this service. Our Mohs laboratory produce high quality frozen sections for Mohs trained dermatologists to read allowing them to see beneath the visible disease.
The exact location of the cancer cells is pinpointed using a special mapping technique. The cancerous tissue can then be removed in stages until only normal tissue remains. The main advantages of Mohs are its high cure rate and the removal of tissue only where cancer cells are present. This means that the surrounding healthy tissue remains unharmed and reduces the risk of scarring or skin disfigurement. This unique technique is particularly suited for areas where preserving as much normal tissue as possible is extremely important, such as tumours around the eyes, nose, lips and ears.
This service is accredited under the United Kingdom Accreditation Service to International Standard ISO 15189:2012.