Autoimmune fasciitis triggered by the anti-programmed cell death-1 monoclonal antibody nivolumab

Abstract

A 43-year-old woman with a history of recently diagnosed metastatic melanoma was commenced on systemic therapy with nivolumab, an anti-programmed cell death-1 monoclonal antibody and one of an increasing group of the so-called 'immune checkpoint inhibitors'. She experienced a dramatic complete response within 6 months of initiation. However, in addition to developing incident autoimmune hypothyroidism, she also developed progressive fatigue, proximal weakness, myalgia and dysphagia. Initial investigations with blood tests, electrophysiology and a muscle biopsy were non-specific or normal. Subsequent examination revealed 'woody' thickening of the subcutaneous tissues of the forearms, thighs and calves consistent with fasciitis. MRI and a full-thickness skin-muscle biopsy were ultimately diagnostic of a likely iatrogenic autoimmune myofasciitis. The clinical manifestations only responded partly to prednisolone 30 mg orally and treatment was escalated to include intravenous immunoglobulin. At 3 months, this has only resulted in a modest incremental improvement.

Keywords: muscle disease; musculoskeletal and joint disorders; musculoskeletal syndromes; oncology; unwanted effects / adverse reactions.

Figure 1

Coronal and representative axial T2 short-tau inversion recovery sequence MRI images of both thighs demonstrating marked signal hyperintensity in a perimysial and perifascicular distribution, consistent with fasciitis.

Figure 2

Coronal and representative axial short-tau inversion recovery sequence MRI images of both calves again demonstrating marked signal intensity in a perimysial and perifascicular distribution consistent with fasciitis.

Figure 3

CD3 immunostaining (original magnification ×100) of right thigh full-thickness biopsy demonstrating T-lymphocyte-mediated inflammation preferentially affecting fascia (above right) with minimal endomysial activity present in perifasicular muscle (below left).