A Severe Case of Nuclear Matrix Protein-2-Positive Dermatomyositis With Negative Malignancy Workup

Area of Science:

• Rheumatology
• Immunology
• Oncology

Background:

• Dermatomyositis (DM) is an idiopathic inflammatory myopathy characterized by muscle weakness and skin manifestations.
• Nuclear matrix protein 2 (NXP-2)-positive DM is a rare subtype with a significant association with underlying malignancy.

Observation:

• A 63-year-old male presented with proximal muscle weakness, subcutaneous edema, and severe dysphagia, consistent with NXP-2-positive DM.
• The patient required prolonged hospitalization and percutaneous endoscopic gastrostomy (PEG) tube placement due to refractory symptoms.

Findings:

• The patient demonstrated significant improvement following treatment with prednisone, azathioprine, rituximab, and intravenous immunoglobulin (IVIG).
• No evidence of malignancy was detected in the patient for over two years post-treatment.

Implications:

• This case emphasizes the severe presentation potential of NXP-2-positive DM.
• Aggressive, multi-agent immunosuppressive therapy, including second-line agents like rituximab and IVIG, may be necessary for managing severe NXP-2-positive DM.
• Early recognition and management are crucial for improving outcomes in patients with this rare DM subtype.