American clinicians, including Andrew Mammen, the researcher behind the first descriptions of immune-mediated necrotizing myopathy (IMNM), take stock of this pathology and highlight its atypical forms:
- after recalling the usual framework of this myopathy characterised by muscle weakness and the positivity of autoantibodies against the SRP and/or HMGCR proteins,
- the authors have compiled the atypical observations of IMNM reported in the literature,
- They list forms which may mimic limb-girdle muscular dystrophy, facioscapulohumeral muscular dystrophy (FSHD), distal myopathy, oculobulbar involvement, megaconial myopathy or isolated hyperCKaemia,
- an algorithm summarising the steps to be taken to arrive at a diagnosis of definite IMNM.
The authors question the concept of seronegative IMNM, preferring the term overlapping myositis.
