Sclero-myositis 4.75/5 (4)

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Scleroderma myositis overlap syndrome "sclero-mositis"

Histopathologic muscle-biopsy images of SSc-PM overlap patient versus PM patient. Left side (A, C, E): SSc overlap patient. Right side (B, D, F): PM patient. (A) Hematoxylin & eosin (H&E) stain; upper marker, necrosis; lower marker, lymphocytic infiltrate; (B) H&E stain; marker, lymphocytic infiltrate; (C) MAC stain; markers, MAC upregulation; (D) MAC stain, no upregulation; (bv 02D7; (E) MHC class I stain, sarcolemmal MHC class I upregulation; (F) MHC class I stain, sarcolemmal and diffuse cytoplasmic MHC class I upregulation.

Scleroderma-myocyte overlap is also called scleromyositis. Bhansing KJ, 2014. CC BY 4.0


Scleromyositis is one systemic connective tissue disease which overlaps between Systemic sclerosis (scleroderma) and (dermato) Myositis. Not all systemic connective tissue diseases can be classified into one or other defined diagnosis. Some show features that overlap between the diagnoses.

In the case of systemic sclerosis, myositis overlaps (scleromyositis as described here), but overlaps occur also in Rheumatoid arthritis, Sjögren's syndrome, MCTD og SLE.

Many of the patients with scleromyositis have a characteristic Antibodies (pm-scl 100 / 75) in the blood samples indicating that this is a separate disease group.


Scleromyositis is defined as one rare disease.

Characteristics of the disease

Symptoms and medical findings are as with systemic sclerosis and myositis (reference: Bhansing KJ, 2014). The lists below are based on selected patients with partial disease progression and are not necessarily representative of the patient group in general:

  • Scleroderma signs (%)
  • Myositis symptoms
    • Muscle weakness (proximal muscle groups) almost 100%
    • Creatine kinase (CK) in blood is elevated 96%
    • Electromyography (EMG) shows pathological changes 88%
    • Muscle biopsy shows the same as in myositis
  • Internal organs
    • Impaired pulmonary function near 100%
    • Lung fibrosis 83%
    • Reduced diastolic heart function 37%
    • Pulmonary hypertension By ultrasound of the heart
      • Pulmonary hypertension is detected at the right catheter in some patients
  • Antibodies
    • ANA 100%
      • pm-scl 75 / 100 34% (reference: Pakozdi A, 2011)
      • Centromer (CENP) 10%
      • SSA / Ro 8%
      • RNP 8%
      • Jo-1 8%
      • Topoisomerase (scl 70)
  •  Muscle biopsy (tissue test)
    • Necrotic fibers 96%
    • Lymphocyte infiltrates 63%
    • Positive MHC Class I Coloring 92%
    • Inflammation 79%
    • COX negative fibers 30%


Typical medical history, clinical findings, laboratory tests, capillaroscopy, EMG, MRI examination of muscles. Biopsy from muscle (most often from the thigh).

Course of disease

The prognosis is individually different depending on whether internal organs are affected. It is also crucial which organs are attacked and if the treatment has a good effect. The overlap syndrome between systemic sclerosis and myositis generally has a high incidence of pulmonary fibrosis. Heart failure occurs in some patients.


As long as disease activity is suspected, patients should be monitored at least annually for measurement of pulmonary and cardiac function, as well as clinical controls. This to detect and treat any complications that may occur.


Basically, one does not want to use corticosteroids. One is reluctant to provide other immunosuppressive treatment without disease manifestations of internal organs. Myositis component is currently treated as myositis, but corticosteroids must be used with caution in order not to trigger "Renal crisis" This is seen in systemic sclerosis. Treatment choices at scleromyositis are therefore highly dependent on the individual disease.


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