Skin biopsy Sophia Otto SA Pathology
RCPA (Royal College of Pathologists of Australasia) The RCPA is the leading organisation representing pathologists in Australasia. Its mission is to train and support pathologists and to improve the use of pathology testing to achieve better healthcare. For those who are not already familiar with this area of medicine, pathology is about the study of the causes of disease and pathologists are the specialist medical doctors involved in the diagnosis and monitoring almost of all acute and chronic illnesses. As a way of background, the College was first established in 1956 and has been responsible for the training and professional development of pathologists since that time. College members come from across Australasia including Australia, New Zealand, Hong Kong, Singapore, Malaysia and Saudi Arabia. The RCPA is also responsible for the promotion of the science and practice of pathology. The RCPA offices are located in the heritage listed, Durham Hall in Surry Hills, Sydney. It is a not-for-profit organisation which is governed by its Council and Board of Directors. The College s current President is Associate Professor Peter Stewart and its CEO is Dr Debra Graves. The College management team consists of up to 30 staff members who administer all aspects of the running of the College.
Durham Hall
Anatomical pathology Chemical pathology Forensic pathology General pathology Genetic pathology Haematology Immunopathology Microbiology Disciplines
Anatomical Pathology Tissue diagnosis of disease Tissue taken from patients in the operating theatre, on the ward or from an autopsy This material is used to make a diagnosis of disease which determines prognosis and guides treatment planning. Diagnoses not only made on solid tissue samples but also separated cells in form of subspecialty of Cytopathology (FNA, exfoliative cytology, PAP)
Anatomical Pathology Histopathology involves the macroscopic examination of tissues, with material then taken for microscopic examination
Tissue Processing The laboratory produce glass slides that are viewed under the microscope by pathologists. The staff who do the tissue processing and make the glass slides are histotechnologists.
Request form
Transport media Formalin (histopathology) Michel s medium (tissue immunofluorescence) RPMI (flow cytometry) Saline or fresh (microbiological evaluation) Gluteraldehyde (electron microscopy)
Specimen Accessioning Tissue specimens received in the surgical pathology laboratory have a request form that lists the patient information and history along with a description of the site of origin. The specimens are accessioned by giving them a number that will identify each specimen for each patient.
A pathologist and/or trainee are also assigned to the case. Specimen accessioning
Gross examination Tissues removed from the body for diagnosis are examined by a pathologist or a technical grosser. A macroscopic description is dictated and all or part(s) of the submitted tissue are transferred into a small plastic cassette The cassette will then be processed to a paraffin block.
What Is Tissue Processing? Tissue processing is the technique of getting fixed tissue into paraffin Thin microscopic sections of the tissue sampled is produced. Automation consists of an instrument that moves the tissues around through the various agents on a preset time scale.
Principals of Tissue Processing Fixation-preserve tissues permanently in as life-like a state as possible and stops autolysis. Dehydration-the water from the tissues must be removed by dehydration. This is usually done with a series of alcohols, 75% to 85% to 100%. Clearing- consists of removal of the dehydrant with a substance that will be miscible with the embedding medium (paraffin) e.g. Xylene, Isopropanol. Impregnation of paraffin- tissues embedded in paraffin, which is similar in density to tissue).
What is a skin biopsy? Skin biopsy is a biopsy technique in which a portion of or all of a skin lesion is removed. This is sent to a pathologist for microscopic diagnosis. It is usually done under local anaesthetic in an outpatient setting. The pathology results are generally available within 2-4 days. Although commonly performed by dermatologists, these biopsies can be performed by any medical practitioner
Limitations When the biopsy is performed incorrectly, and without appropriate clinical information, a pathologist's interpretation of a skin biopsy can be severely limited.
Moh s surgery During the surgery, after each piece of tissue is removed, while the patient waits, the pathologist examines the tissue specimen for malignancy, and that examination informs the surgeon where to remove tissue from next. The surgeon performing the procedure is also the pathologist reading the specimen slides.
Skin biopsy Shave biopsy Punch biopsy Incisional biopsy Excisional biopsy
Normal skin Stratum corneum (Stratum lucidum) Stratum granulosum Stratum spinosum Stratum basale
Surgical Sieve 1. Congenital 2. Acquired Vascular Infective Traumatic Autoimmune Metabolic Inflammatory Neurological Neoplastic Degenerative Environmental Idiopathic
Important clinical information Patient demographics Requesting clinician s information Clinical history -duration -immunocompromised or not -overseas travel Clinical morphology (+/- photographs) Suspected diagnosis or diagnoses
What is the clinical question? Medical: rashes Surgical: tumours Infections: bacterial, fungal, Mycobacterial
Cherry angioma
Seborrhoeic keratosis
Sebaceous hyperplasia
Basal cell carcinoma (BCC)
Squamous cell carcinoma (SCC)
Keratoacanthoma
Additional Modalities Histochemical stains Tissue immunofluorescence Immunohistochemical stains
PASD
Gram stain
Ziehl Neelson stain
Fibrinogen at dermo-epidermal junction in lichen planus
IgG staining of intracellular cement substance in pemphigus vulgaris IgG positive intracellular cement substance in pemphigus vulgaris
Linear IgG and C3 at dermo-epidermal junction in pemphigoid
IgA of superficial dermal vessels in HSP (Henoch Schonlein purpura)