What Is a Dermatopathologist?
A dermatopathologist is an expert in the microscopic diagnosis of diseases of the skin. This entails the examination and interpretation of specially prepared tissue sections, cellular scrapings, and smears of skin lesions by means of light microscopy, electron microscopy, and fluorescence microscopy (ABD, 2017). Dermatopathologists often have general training in clinical dermatology, pathology, or a combination of both.
Dermatopathology is a medical sub-specialty within the fields of dermatology and pathology that focuses on the study and diagnosis of diseases of the skin and associated mucous membranes, cutaneous appendages, hair, nails and subcutaneous tissues (Dermatologist, 2017).
Pathology is the study of the cause, course and progression of a disease, as well as any complications arising from that disease. Pathologists are trained to identify and interpret pathological specimens to diagnose diseases. Anatomic pathology, also known as histopathology, is the study of structural and compositional changes that occur in organs and tissues caused by a disease. Dermatopathology is the study and description of structural and compositional changes of the skin due to a skin disease.
A dermatologist is a physician who is trained to evaluate and treat children and adults with benign and malignant disorders of the skin, hair, nails and adjacent mucous membranes. A dermatologist has had additional training and experience in the following (ABD, 2017):
Dermatologists also manage cosmetic disorders of the skin, including hair loss, scars, and the skin changes associated with aging.
The Difference Between Dermatology and Dermatopathology
The difference between dermatology and dermatopathology is simple: dermatology is visual, whereas dermatopathology is analytical. Dermatologists examine skin, and Dermatopathologists examine microscope slides. There are many unknowns with a visual examination, and a dermatopathologist can help answer those questions to help narrow the scope or origin of the possibility of disease. Dermatologists directly interact with patients, and dermatopathologists typically work in a laboratory, with little to no patient contact.
Other Dermatology Sub-Specialties
A pediatric dermatologist is a dermatologist who has additional training and expertise in the evaluation and management of skin diseases which occur more commonly or exclusively in children. Examples include: all types of birthmarks, neonatal dermatology, genetic diseases of the skin, pediatric infections or inflammatory processes and skin diseases in children with complex medical conditions requiring coordinated multispecialty care (ABD, 2017).
Cosmetic dermatologists work with patients who have the desire for improvements to their appearance, although there may be no medical reason related to their treatment. Examples of cosmetic dermatology procedures include Botox, facelifts, diminishing the appearance of scar tissue, liposuction and eyelifts. Most cosmetic dermatology procedures are minimally invasive.
Immunodermatology is the practice of diagnosing and treating skin disorders that present due to a dysfunction of the immune system. Exposures to chemicals, biological agents or microorganisms and other foreign materials can lead to a defective response of the immune system displayed in symptoms such as irritation, rash, lesions, and many others.
Named after its founder, Dr. Frederic E. Mohs, Mohs surgery is a micrographic skin procedure that involves a precise removal of cancerous skin tissue or layers, leaving the cancer-free tissue behind. This type of surgery is considered the most effective technique for treating basal cell carcinomas and squamous cell carcinomas. There are multiple stages of this procedure, as each skin layer is analyzed by a dermatopathologist for the presence or absence of cancer cells or indications of the disease. This allows for the smallest amount of skin removal possible, thus preserving healthy tissue and skin cells.
Mohs surgery is performed by a team of physicians, including a surgeon to remove the diseased tissue, a dermatopathologist to analyze the specimen, and a surgeon to close the wound or perform reconstruction. The surgery is typically done in one day, and breaks are taken while the dermatopathologist analyzes the tissue removed.
Teledermatology involves the audio, visual and data telecommunication technologies that are used by medical professionals to exchange patient information. This allows for easier discussion and consultation between dermatologists and other medical specialists to provide comprehensive medical care and obtain second opinions for skin cancer or other diagnoses.
Skin Biopsy Examination
The interpretation of skin biopsies and specimens is an extremely complex task, as there are many skin diseases with similar inflammatory processes or patterns. The skin biopsy examination done by a dermatopathologist involves a scientific method and process to ensure accurate evaluation and diagnosis. The specimen is first processed and stained with a solution that will indicate the presence of cancerous skin cells, or the presence of other disease to identify the origin, nature and distribution of the cells that are present. In some cases, the dermatopathologist will look for substances deposited in the skin, such as iron or melanin.
The dermatopathologist evaluates the structure of the skin, including the epidermis, dermis, subcutis, fascia and underlying structures. In some cases, they may be able to definitively identify the disease, and in other cases, they may be able to provide several different possible diagnoses. The results of the biopsy are then integrated with additional clinical information to create a final diagnosis and treatment plan.
There is the possibility of an erroneous biopsy diagnosis, which is why it is important to evaluate the entire clinical record of the patient. Inaccurate diagnoses may be due to a variety of errors, including the following:
Dermatopathologists receive extensive education and training in skin biopsy examination, and they focus on reducing the possibility for error as much as possible. With any scientific method or examination, there is always a slight possibility for error, but if used in combination with clinical data, these errors can be significantly reduced.
Testing Methods for Skin Irritation
Patch testing for allergic response is used to obtain information on the irritancy of chemicals on human skin. The skin of laboratory animals is thinner and more sensitive to irritation than human skin. In-vitro testing using human epidermal cell cultures has been increasingly used to test the potential irritation factor of various materials including cosmetics, industrial chemicals, and pharmaceuticals. Models have been developed to compare the release of inflammatory mediators and mitochondrial response different chemicals produce in the epidermal cells. In addition, DNA microarray and proteomic analysis methods are used to identify cellular responses.
Chloracne is the most disfiguring type of acne in humans. It is caused by exposure to PCBs and TCDD and other chloracnegens. Chloracne is characterized by comedones and straw-colored cysts present behind the ears, around the eyes, shoulders, back, and genitalia. In additions, increased hair growth in odd locations, hyperpigmentation, brown discoloration of finger and toe nails, conjunctivitis, and eye discharge may be present. Liver, nervous system, and stem cell effects are also associated with chloracne.
Ultraviolet Skin Exposures
Ultraviolet (UV) rays are thought to be a both a mutagen and carcinogen. Both UVA and UVB exposures have been associated with the development of melanoma and nonmelanoma skin cancers. Most skin cancers in the United States are now UV-induced. Nonmelanoma Skin cancers (NMCS) and cutaneous malignant melanoma are the most common skin cancers. UVB exposure induces pyrimidine dimers and 8-oxoguanine modifications, which elicit genetic mutations.
P-53 (an amino acid protein) is a major target of UVB damage. P-53 is a protein that has a major role in regulating gene expression, specifically tumor-suppression. Tumor-suppression genes encode proteins to inhibit cell division, promote DNA repair or apoptosis on DNA damaged sites. It is detectable in most squamous cell carcinomas. The loss or damage to p53 prevents cell repair and apoptosis, therefore the mutated cells have a growth advantage. UV light also has immunosuppressive effects that may allow skin tumor survival.
The Stages and Progression of Skin Cancer
Initiation is the first step in the process and is considered a stable, heritable change. This stage is a rapid, irreversible process that results in a mutation induced by a carcinogen. Initiating agents lead to genetic changes such as mutations and deletions. Most chemical carcinogens that function in the initiation stage are indirect-acting genotoxic compounds that must be metabolized in the target cell to produce DNA damage. The initiating event is fixed when the DNA damage is not repaired, or repair is incomplete, which can lead to inappropriate base pairing and formation of mutations.
Once initiation begins, there are several possible outcomes for the initiated cells:
Promotion involves the selective clonal expansion of initiated cells to produce a pre-neoplastic lesion. Tumor promotors function in this stage. They act through several mechanisms involving gene expression changes that can result in cell proliferation and/or the inhibition of apoptosis. Nongenotoxic carcinogens function at this stage. Growth of pre-neoplastic lesions requires repeated applications or continuous exposure to tumor promotors. Promotion can be reversible, if the agent is removed, the cell may return back to the initiation stage. Typically, tumor promotors have a threshold for effects: at low doses they do not induce cell proliferation.
Progression is the final stage of the carcinogenesis process, and it involves benign preneoplastic lesion conversion into a neoplastic cancer. DNA synthesis in cell proliferation in the preneoplastic lesions is increased, and additional DNA damage and chromosomal damage can occur. This drives the transfer from preneoplastic into neoplastic cell populations. Cells accumulate mutations and can outgrow surrounding cells and to attract necessary nutrients for continued growth. Autonomous and/or lack of growth control is achieved, and spontaneous progression can also occur in mitotically active initiated cells.
Allergic Contact Dermatitis and Irritant Contact Dermatitis
Irritant contact dermatitis accounts for 80% of all contact dermatitis cases. It results from direct action of toxins or toxicants on the skin. Known contact dermatitis irritants cause adverse effects depending on concentration and exposure time. Some chemicals including strong acids, alkalies, and strong oxidizers and reducing agents can cause second degree burns that can lead to scarring. Some plants can also cause irritant contact dermatitis by stimulating the release of proinflammatory cytokines.
Cumulative irritation can also occur from repeated exposure to mild irritants such as soaps or detergents. Inflammation and eczema can occur from chronic cumulative irritation, in addition to skin thickening and/or hardening. Areas with sensitive skin, i.e. eyelids, are therefore more sensitive to toxin/toxicant exposure. There is also a large variation in response between individuals. Incidences are seen in 20% of children in industrialized societies, and individuals with a propensity of produce IgE antibodies to allergens and suffer from hay-fever have higher frequency of persistent dermatitis. In addition, a genetic defect in the protein filaggrin is associated with persistent dermatitis and can also lead to the development of asthma.
Allergic contact dermatitis is a delayed T-cell mediated hypersensitive response. The chemical penetrates the lipid barrier and is introduced into the immune system by attaching to carrier proteins. The antigens then attach to Langerhans cell surfaces, and over a 1-3-week period, memory T-cells are generated and enter circulation. Exposures to the same chemical subsequently cause clonal proliferation of Langerhans cells and release of inflammatory cells. Thousands of chemicals can induce allergic contact dermatitis.
With irritant dermatitis, the response is typically proportional to the dose concentration and exposure time; whereas allergic dermatitis is a response with very small doses, although higher doses are associated with increased sensitization, and smaller doses tend to have a cumulative effect. Many chemicals and some toxins are associated with both irritant and allergic contact dermatitis.
Equipment used by a Dermatopathologist
The total equipment needs of a dermatopathology lab can cost at least $50,000 but may far exceed that cost depending on the size of the laboratory and the process techniques utilized (Derm, 2017). Equipment includes a tissue processor, embedding center, microtome, water bath, incubator, manual or automatic slide staining system, fume hood and flammable storage cabinet. Computer systems and software for generating specimen and pathology reports are often used as well.
The History of the American Society of Dermatopathology
The American Society of Dermatopathology (ASD) was established by a group of nine men, some who also served on the Committee on Pathology of the American Academy of Dermatology (AAD) in December of 1962. In 1963, the first scientific meeting of the ASD was held, which is considered the beginning of significant developments in the sub-specialty field of dermatopathology.
Prior to the establishment of the ASD, the major forum for the presentation and discussion of anything new in dermatopathology was in the dermatopathology courses and the Clinicopathologic Conference (CPC) of the AAD (Freeman, 1993). Gradually, the ASD became the focal point for discussing advancements and innovations in the dermatopathology medical field.
The initial concept of the ASD was to maintain a small relatively exclusive group of physicians who were intensely interested in and actively practicing the subspecialty (Freeman, 1993). Free discussion was encouraged, and an organizational structure was developed, with requirements for attendance and acceptance established.
The Merging of Dermatology and Pathology
Although “dermatopathology” was first coined by Henry Seguin Jackson in 1792, progression toward the integration of clinical findings with pathological findings seen on a microscopic level was slow (Derm, 2017). Some of the earliest treaters of skin disease were pathologists who had already learned the skills of careful observation and analysis of morphological data that make up the core of work of both dermatology and pathology specialties (Freeman, 1993). The discovery of the stains used for microscopic analysis and the development of histological techniques led to the evolution of dermatology toward histopathology.
Today’s dermatopathology is done through microscopic evaluation using histological, histochemical, immunological, ultrastructural, molecular and microbiological techniques (Derm, 2017). There are more than 1,500 existing skin diseases or conditions that have been identified, which presents a significant challenge for clinical dermatologists.
How to Become a Dermatopathologist
It will take over a decade to become a licensed dermatopathologist, due to the extensive education and clinical training requirements. A future dermatopathologist should make sure they apply to an accredited medical school, residency or fellowship program to avoid issues with licensing and certification.
The first step toward becoming a dermatopathologist is to complete an undergraduate degree. Although there are no specific requirements for a major, most students major in a science such as chemistry or biology, while some may choose a social science major such as psychology or sociology. Maintaining a high grade point average, participating in extra-curricular activities, and volunteering at a medical center or hospital are all recommended for undergraduates aspiring to get into medical school.
During the third year of an undergraduate program, students will need to take and pass the Medial College Admissions Test (MCAT) examination to be accepted into an accredited medical school. The higher the MCAT score, the greater your chances are of being accepted, although there is a minimum score required to pass the exam.
A dermatopathologist must obtain a Doctor of Medicine (M.D.) or Doctor of Osteopathy (D.O.) degree from an accredited medical school or school of osteopathy. During the first two years of medical school, the focus will be on coursework including biochemistry, physiology, medical law, pharmacology and many others. The last two years of medical school involve hands-on training in a clinical setting under the direct supervision of a licensed physician. During this time, students gain exposure to a wide variety of medical specialties including dermatology, pediatrics, internal medicine, emergency medicine and other specialty fields.
A future dermatopathologist will complete residency training in dermatology, anatomic pathology or anatomic and clinical pathology, which may take anywhere from 3 to 5 years. The residency program should be accredited by the American Osteopathic Association (AOA), and a fellowship must be approved by the Accreditation Council for Graduate Medical Education (ACGME). The residency training provides additional practice in the clinical dermatology or pathology field, and provides some exposure to the sub-specialty of dermatopathology.
Although all general dermatology residents receive comprehensive training in each of these subspecialties, candidates who pursue the additional year(s) of training in subspecialty fellowships will have met additional standards and qualifications that will prepare them for specialized careers in teaching, research, and/or the practice of these subspecialties (Derm, 2017).
The fellowship program allows the student to receive additional hands-on experience in the sub-specialty field of dermatopathology. A minimum of 4 months of training must be exclusively devoted to dermatopathology, and be part of at least half of the entire fellowship program, with anatomic pathology or dermatology as the focus. The best fellowship training opportunities are at hospitals or medical centers who analyze a high volume of specimens, because the student gets more exposure to unique and challenging diagnoses.
Licensing and Certification
A dermatopathologist must be licensed in the state they wish to practice in, and each state has its own unique requirements, although many of them are similar in nature. Doctors in this medical field must pass an examination to become both licensed and certified. A valid and unrestricted license is required to qualify for and maintain certification, in addition to other eligibility requirements.
The certification process consists of a thorough evaluation and examination of the knowledge, experience and skills of a dermatopathologist. The American Board of Medical Specialties (ABMS) oversees 24 specialty boards, including the American Board of Dermatology (ABD) and the American Board of Pathology (ABP). Certifications have a 10-year limit, during which time continuing education and training is required.
In addition to a valid license to practice, eligibility requirements for certification include completing a M.D. or D.O. degree from an accredited institution, completing a residency program (assessment and documentation of performance may be required), and passing a written and clinical examination by the certifying organization.
Most dermatopathologists work in a laboratory setting within a hospital or medical center, although there are some opportunities to work in academic and government institutions. According to Salarylist.com, the average salary for dermatopathologists is over $219,000 annually.
ABD – American Board of Dermatology. What is a Dermatologist? 2017. Retrieved November 7, 2017 from: https://www.abderm.org/public/what-is-a-dermatologist.aspx.
Yung, Anthony, MD. Dermatopathology. Dermatologist, Waikato District Health Board, Hamilton, New Zealand, 2007. Retrieved November 7, 2017 from: https://www.dermnetnz.org/topics/dermatopathology/
Robert G. Freeman, MD. The History of the American Society of Dermatopathology. Journal of Cutaneous Pathology 1993: 279-287. Retrieved November 7, 2017 from: http://www.asdp.org/about-asdp/history/
The Dermatologist. Subspecialties in Dermatology: Dermatopathology. 2017. Retrieved November 8, 2017 from: https://www.the-dermatologist.com/content/subspecialties-dermatology-dermatopathology
Klaassen, Curtis D. Casarett and Doull’s Toxicology: The Basic Science of Poisons, 8 ed., 2013.