Histopathological knowledge of dermatologists and dermatological knowledge of histhopathologists and their cooperation help to more clearly diagnose and classify inflammatory skin diseases and skin cancers: it is no coincidence that they correlate positively and strongly. The fact is that the same pathology in different periods of its development is characterized by different, often complex, masking each other structural changes, which causes difficulties in differential diagnostics. Histological diagnosis is based on systematic analysis of pathohistological patterns. The pathohistological diagnosis of most inflammatory skin diseases is based on 6 pathohistological reactions: psoriatic (hyperkeratosis, acanthosis, parakeratosis, papillomatosis, etc.), lychenoid/ interface (compact orthokeratosis, diskeratosis, alternation of hyper- and hypogranulosis, lichenoid lymphocyte infiltration, vacuolar or hydropic changes in basal keratinocytes, etc.), spongious (intraepidermal spongiosis, exocytosis, neutrophilic and/or eosinophilic spongiosis, etc.), granulomatous (content of epithelioid and giant cells, asteroid and Schaumann bodies, necrobiosis, etc.), vesiculo-bullous (spongiosis, vacuolization, acantholysis, etc.), vasculopathic (inflammation of the vascular walls, hemorrhagic and ischemic changes of the vessels, infiltrative erythema, petechiae, purpura, nodules, livedo, etc.). The article considers dermatological and dermatooncological problems in the context of correlation of clinical and histological data with modern methods of optical skin diagnosis, which certainly increases the significance, especially for complex, dermoscopic, clinical and pathohistological evaluations.