Benjamin Ellezam


Benjamin Ellezam1, Nathalie Langlais2

1Division of Pathology, CHU Sainte-Justine, Montréal, QC, Canada

2Division of Rheumatology, CHR de Lanaudière, St-Charles-Borromée, QC, Canada

Clinical Summary

A 48-year-old male with a history of Raynaud phenomenon and rheumatoid arthritis stable with hydroxychloroquine presented after 2 months of slowly progressive proximal weakness and myalgia. Lab results included elevated creatine kinase (10x normal), positive anti-nuclear antibodies (1/2560, granular pattern) and normal levels of rheumatoid arthritis activity serologic markers. Thoracic scan was normal except for a prominent esophagus. Electromyography or muscle MRI were not performed. Quadriceps muscle biopsy was obtained.

Discussion points

  1. What is the differential diagnosis on H&E?
  2. What is the differential diagnosis with the submitted immunohistochemistry?
  3. What further studies are needed to resolve the differential diagnosis?
Reveal Diagnosis

Case of Scleromyositis

Additional relevant investigations and comment.
-Collagen-4 IF revealed large-caliber endomysial capillaries with mild dropout
-MxA IHC showed lack of sarcoplasmic expression (ruling out dermatomyositis)
-EM revealed marked capillary basement membrane reduplication, confirming the diagnosis.
-In some cases, scleromyositis presents before the patient fulfills the clinical criteria for SSc (e.g. skin thickening). High dose
corticotherapy given for other auto-immune myositis can have detrimental effects in patients with systemic sclerosis. Early
organ surveillance is important in SSc patients.

Giannini et al (2023) Scleromyositis: A distinct novel entity within the systemic sclerosis and autoimmune myositis spectrum.
Implications for care and pathogenesis. Front. Immunol. 13:974078