Pathomorphological Changes in Childhood Myositis

Idiopathic inflammatory myopathies (IIMs) occur in childhood and adulthood with different incidences. The key role of autoantibodies in pathogenesis has recently emerged and it has become clear that these autoantibodies are useful for prognostic purposes. The morphological aspects of different types of myositis differentiate them as well, and together with autoantibody profiles they define distinct entities. This classification allowing a precise attribution of these conditions (IIMs) to disease entities can be a valid and useful basis for clinical decisions with respect to follow-up of patients and their therapeutic approach.

The spectrum of myositis in childhood is broad, with dermatomyositis certainly forming the largest sub-entity, whereas some of them occur in adulthood exclusively (e.g., sporadic inclusion body myositis).

The aim of this presentation is to present the different myositis entities and their characteristic morphological features, to discuss the value of autoantibody testing and its combination with muscle biopsy. Differences and specificities of myositis in childhood as opposed to the respective diseases in adulthood will also be addressed.