What is dermatopathology?
Dermatopathology is a subspecialty of pathology.
- Pathology is the study of diseases. It includes the study of the causes, course and progression and the complications that arise from the disease.
- Anatomic pathology, or histopathology, refers to the study of the structural and compositional changes that occur in organs and tissues as a result of disease.
- A pathologist is a doctor trained in anatomic pathology that examines, describes and interprets pathological specimens to arrive at a specific finding or diagnosis.
- Dermatopathology is the study and description of structural and compositional changes that occur in skin disease.
From a practical point of view, dermatopathology involves the microscopic examination, description and interpretation of biopsy specimens obtained from the skin. This is usually carried out by a general pathologist (who may or may not have had specific training in dermatopathology) or by a dermatopathologist (a doctor trained specifically in dermatopathology, but who may not have fully trained in anatomic pathology). Dermatopathologists often have training in clinical dermatology.
The interpretation of skin specimens can be complicated and difficult, as many diverse inflammatory skin diseases share the same basic inflammatory process or pattern. The final diagnosis requires clinical input and clinicopathological correlation.
How are skin biopsy specimens examined?
Skin biopsy specimens are processed and then stained with Haematoxylin and Eosin (H&E). Eosin is acidic in nature and stains basic / alkaline structures red/pink. Haematoxylin is alkaline, and stains acidic structures (e.g. deoxynucleic acid, ribonucleic acid within cell nuclei) blue. Depending on the observed dermatopathological pattern present and/or the clinical features, special stains may be requested to identify agents causing the condition (e.g. bacteria or fungi), specific substances deposited in the skin (e.g. amyloid, iron or melanin) or specific markers to identify the origin, nature and distribution of cells in the specimen being examined.
The specimen is systematically examined by looking at the structure of the epidermis, dermis, subcutis, fascia and underlying structures. Based on the findings, the pathologist may come up with a definitive diagnosis, or list several possible explanations, creating a differential diagnosis. The integration of clinical information in conjunction with the pathological findings generates the final diagnosis. It is in this correlation of clinical and pathologic findings that experience in clinical dermatology can be very helpful.