Dermatopathology
Dermatopathology is a specialized medical field that focuses on diagnosing skin diseases through the examination of external clinical features and microscopic changes in skin tissue. Practitioners known as dermatopathologists are trained in pathology and histology, allowing them to interpret tissue samples that have been biopsied from patients. These professionals play a crucial role in identifying various skin conditions, including allergies, infections, autoimmune disorders, and skin cancers, although they typically do not provide direct treatment.
The process begins with a dermatologist conducting a physical examination of the skin. If further analysis is needed, they send tissue samples to a dermatopathologist, who uses techniques such as staining and microscopic observation to assess the samples. Significant advancements in dermatopathology, including the use of artificial intelligence, have enhanced diagnostic accuracy by enabling the analysis of large datasets of digitized images. Overall, dermatopathology serves as an essential link in understanding and diagnosing skin-related health issues, contributing to informed treatment decisions.
Dermatopathology
Anatomy or system affected: Immune system, skin
Definition: The study of the causes and characteristics of diseases or changes involving the skin
Science and Profession
Dermatopathology is the medical specialty that utilizes external clinical features of the body’s surface, as well as histological changes that are observed microscopically, to define diseases of the skin. The dermatopathologist is a physician who has specialized in pathology, the clinical study of disease, and/or in histology, the microscopic study of cells and tissues. Although the specific clinical field of this specialty involves the skin, the practitioner has also received broader training in pathology.
The skin is the tough, cutaneous layer covering the entire body surface. In addition to the epidermal tissue of the surface, the skin contains an extensive network of underlying structures, including lymphatic vessels, nerves and nerve endings, and hair follicles. The dead cells on the surface of the epidermis continually slough off, to be replaced by dividing cells from the underlying basal layers. As these cells proceed to the surface, they mature and die, forming the outer layer of the skin.
When a disease or condition of the skin is diagnosed, the initial observations are often carried out by a general practitioner or dermatologist. This person will make a gross observation; if warranted, biopsies or samples of the lesion may then be provided to the dermatopathologist for examination. The most common forms of skin lesions are those associated with allergies, such as contact dermatitis associated with exposure to plant oils (such as poison ivy) or chemicals (such as antibiotics). More serious dermatologic diseases may also require diagnosis. Specific kinds of lesions often represent specific types of disease; these may include a variety of forms of skin cancers, lesions associated with bacterial or viral infections (such as impetigo or herpes simplex), and autoimmune disorders (such as lupus). The dermatopathologist may also be concerned with diseases of underlying tissue, such as lymphoid cancers or lesions penetrating mucous membranes.
The dermatopathologist is involved in the diagnosis of the problem but generally is not involved with specific forms of treatment. Nevertheless, their recommendations may certainly influence decisions. The major role of the dermatopathologist is observation; this may then be followed by an interpretation of results, including a possible prognosis or outcome.
Diagnostic and Treatment Techniques
The clinical examination of skin lesions initially falls within the realm of the dermatologist. If the gross observations are insufficient to warrant diagnosis, however, a sample of the lesion can be sent to the dermatopathologist for further examination. In addition to the tissue sample, information on the age, sex, and skin color of the patient should be included, along with any history of the suspected condition.
If the lesion is superficial, as in dermatoses such as warts or even certain types of cancer, a superficial shave biopsy is sufficient for examination. A deeper section of tissue is necessary if the lesion involves an infiltrating tumor, inflammation, or possible metabolic problems. The specimen is immediately placed in a fixative solution, such as formalin, to prevent deterioration.
The dermatopathologist initially embeds the sample in paraffin, which can be sectioned into thin slices after hardening. The tissue is stained, most commonly with hematoxylin and eosin (H & E), and observed microscopically.
Anything about the cells that is out of the ordinary may be helpful in the diagnosis of the problem. For example, in the case of basal cell carcinoma, the cells may be abnormally shaped, with enlarged nuclei. They may also be observed infiltrating other layers of tissue. With contact dermatitis, the lesion is characterized by infiltration of large numbers of white blood cells, particularly lymphocytes, with their easily observed large nuclei. Edema, the abnormal accumulation of fluid, is also common with these types of lesions.
The presence of bacteria, as with boils or impetigo, warrants the use of antibiotics, unlike other inflammatory lesions. In this matter, the dermatopathology of the sample can determine the appropriate form of treatment.
While dermatopathology is primarily observational, recommendations regarding treatment may be made by its practitioners. For example, the study of a sample for the type and extent of cancer may lead to a recommendation concerning how extensive the surgical removal of the tumor should be.
Perspective and Prospects
The use of the skin's physical appearance as a means of diagnosis represents one of the earliest attempts to understand disease. With the microscopic examination of tissue, first performed during the nineteenth century, it became possible to match the presence of histological lesions to specific diseases and to differentiate these diseases from one another.
The field of dermatopathology was greatly refined during the twentieth century. The development of differential and immunological staining methods allowed for a greater understanding of the roles played by the wide variety of cells in the body. For example, the dendritic cells of the skin were found to have a critical function in the immune responses that begin at that level.
In many Western countries, there was a significant shift during the twentieth century in the types of skin disease most commonly seen, mostly reflecting changes in lifestyle. The prevalence of malignant melanomas and basal cell carcinomas became much higher as a result of increased exposure to sun during leisure hours. Recognizing such problems has become an important aspect of training clinicians less specialized than dermatopathologists, such as family physicians.
A technological development that has reached critical maturity in the 2020s has been Artificial Intelligence (AI). Along with other industries and medical fields, dermatopathology is poised for AI to have significant impacts. A key area will be diagnosis. Analysis techniques had previously relied on practices such as inspecting samples through microscopes and glass slides. AI allows machines to perform analysis by inspecting large datasets of scanned, digitized images. Using an example of melanoma, AI allows learning to distinguish between malignant and benign melanoma lesions. These diagnoses are done with great accuracy and with precise classifications. These classifications will then inform the types of treatments that are delivered to patients.
Bibliography
Busam, Klaus J., ed. Dermatopathology. Philadelphia: Saunders/Elsevier, 2010.
Caputo, Ruggero, and Carlo Gemetti. Pediatric Dermatology and Dermatopathology: A Concise Atlas. Washington, DC: Taylor & Francis, 2002.
"Health Information Index." National Institute of Arthritis and Musculoskeletal and Skin Diseases, 2013.
Jartarkar, Shishira. "Artificial Intelligence: Its Role in Dermatology." Indian Journal of Dermatology, Venereology, and Leprology, 13 Dec. 2022, ijdvl.com/artificial-intelligence-its-role-in-dermatopathology. Accessed 7 Aug. 2023.
Jartarkar, Shishira, et al. "Artificial Intelligence in Dermatopathology." Journal of Cosmetic Dermatopathology, 22 Dec. 2022, https://onlinelibrary.wiley.com/doi/10.1111/jocd.15565. Accessed 7 Aug. 2023.
McKee, Phillip. A Concise Atlas of Dermatopathology. New York: Gower Medical, 1993.
Mehregan, Amir H., et al. Pinkus’ Guide to Dermatohistopathology. 6th ed. Norwalk, Conn.: Appleton & Lange, 1995.
"Skin Conditions." MedlinePlus, 10 July 2013.
Tierney, Lawrence M., Stephen J. McPhee, and Maxine A. Papadakis, eds. Current Medical Diagnosis and Treatment. New York: McGraw-Hill Medical, 2010.
Weedon, David. Skin Pathology. 3d ed. New York: Churchill Livingstone/Elsevier, 2010.
Wells, Amy, et. al. "Artificial Intelligence in Dermatopathology: Diagnosis, Education, and Research." Journal of Cutaneous Pathology, 26 Jan. 2021, onlinelibrary.wiley.com/doi/10.1111/cup.13954. Accessed 7 Aug. 2023.
"What Is a Dermatopathologist?" American Academy of Dermatology, 2013.