Board Review: Dermatologic Pathology Patterns

Overview / Definition Dermatologic pathology encompasses a wide range of skin disorders characterized by distinct morphologic patterns. These patterns can aid in the diagnosis of various conditions, including inflammatory, infectious, autoimmune, and neoplastic diseases. Recognizing these patterns is essential for effective patient management and treatment planning. Epidemiology The prevalence of dermatologic conditions varies widely depending on the specific pathology. Some key points include: Acne vulgaris affects approximately 85% of adolescents and young adults. Psoriasis has a prevalence of about 2-3% in the general population. Melanoma incidence has been steadily increasing, particularly in fair-skinned individuals. Pathophysiology / Mechanism The pathophysiology of dermatologic conditions is diverse. Below are some examples illustrating common mechanisms: Acne vulgaris: Results from follicular occlusion, increased sebum production, and Propionibacterium acnes proliferation. Psoriasis: Characterized by increased keratinocyte proliferation due to dysregulated immune responses. Melanoma: Arises from mutations in melanocytes, often linked to UV exposure. Clinical Presentation Each dermatologic condition presents with unique clinical features: Acne vulgaris: Comedones, papules, pustules, and cysts primarily located on the face, back, and shoulders. Psoriasis: Well-defined erythematous plaques with silvery scales, commonly found on extensor surfaces. Melanoma: Asymmetrical, irregularly bordered, multicolored lesions often larger than 6 mm. Diagnosis / Workup Diagnosis typically involves a combination of clinical examination, patient history, and sometimes histopathological evaluation: Clinical examination: Detailed assessment of the lesions and associated symptoms. Dermatoscopy: Useful for evaluating pigmented lesions and differentiating melanoma from benign nevi. Biopsy: Indicated for atypical lesions or when a definitive diagnosis cannot be made clinically. Treat