RESUMO
Histiocytoses are a heterogeneous group of disorders that are characterized by the proliferation and accumulation of reactive or neoplastic histiocytes. Three classes of histiocytoses have been defined: class I, Langerhans cell disease; class II, non-Langerhans cell histiocytic disease without features of malignancy; and class III, malignant histiocytic disorders. Although the disorders in classes I and II usually have a benign appearance on histology and are commonly non-aggressive and self-healing, some can cause debilitating or even fatal outcomes. Such cases beg the question: what stimulates aggressive behavior of a classically benign disease? New molecular information may now provide insight into the driving force behind many of the aggressive histiocytoses. In this article, we review Langerhans cell disease and seven aggressive histiocytoses that can involve skin, discuss histologic features that may forecast a poor prognosis, and discuss the molecular findings that help to explain the pathophysiology of these aggressive histiocytic disorders.
Assuntos
Dermatopatias , Histiocitose/classificação , Histiocitose/patologia , Histiocitose/fisiopatologia , Histiocitose de Células de Langerhans/diagnóstico , Histiocitose de Células de Langerhans/patologia , Histiocitose de Células de Langerhans/fisiopatologia , Histiocitose de Células não Langerhans/diagnóstico , Histiocitose de Células não Langerhans/patologia , Histiocitose de Células não Langerhans/fisiopatologia , Histiocitose de Células não Langerhans/terapia , Humanos , Linfo-Histiocitose Hemofagocítica/patologia , Linfo-Histiocitose Hemofagocítica/fisiopatologia , Transtornos Necrobióticos/diagnóstico , Transtornos Necrobióticos/patologia , Transtornos Necrobióticos/fisiopatologia , Transtornos Necrobióticos/terapia , Prognóstico , Síndrome do Histiócito Azul-Marinho/patologia , Síndrome do Histiócito Azul-Marinho/fisiopatologia , Síndrome do Histiócito Azul-Marinho/terapia , Dermatopatias/diagnóstico , Dermatopatias/patologia , Dermatopatias/fisiopatologia , Dermatopatias/terapia , Xantogranuloma Juvenil/patologia , Xantogranuloma Juvenil/fisiopatologia , Xantogranuloma Juvenil/terapiaRESUMO
Evoked muscle contractions at different stages of necrobiosis were investigated by stimulating impedance myography in patients with vascular pathology and acute or chronic ischemic syndrome of the lower extremities. The threshold and maximum amplitudes and current strength for contraction responses were determined, and the dependence of evoked contractions on stimulating current was evaluated. Approximation of the obtained curves with the well-known force-time excitation curves demonstrated the relationship between excitability and contractility parameters depending on the stage of ischemic necrobiosis. This regularity is a more universal interrelation between muscle electrical characteristics. Electrical characteristics of evoked contractions depend on various factors influencing muscle structure and function.
