Uncovering scleromyositis: no myth, just missed

Scleromyositis (SM), the muscle-specific manifestation of scleroderma, is increasingly recognized as a distinct myositis subset, yet it remains poorly captured by existing classification criteria and absent from therapeutic guidelines. This review provides recent advances in SM with emphasis on challenging presentations and propose a pragmatic diagnostic framework integrating clinical, serological, capillaroscopic, and histopathological data.

Recent studies identify capillaropathy as the unifying pathological hallmark of SM across muscle biopsy subtypes. Nailfold videocapillaroscopy reveals a predominantly scleroderma-active or scleroderma-like microangiopathy discriminating SM from potential myositis mimickers. Recent cohort studies demonstrate that SM confers independent mortality burden and substantial cardiac risk warranting immediate cardiac evaluation at diagnosis regardless of autoantibody profile or histological pattern. Pericyte dysfunction may link capillaropathy to fibrosis in SM, while autoantibodies appear to directly disrupt intracellular pathways, contributing to the shared vasculopathic and profibrotic signature that defines SM as a distinct entity.

SM represents a clinically severe and underrecognized disease spectrum that frequently escapes current classification frameworks. Early SM diagnosis requires systematic integration of clinical, serological, capillaroscopic, and histopathological data, with capillaropathy as the unifying thread. Establishing a consensus SM definition and securing clinical trial inclusion remain the most urgent research priorities.