Paraneoplastic dermatomyositis: a study of 12 cases

Area of Science:

• Dermatology
• Oncology
• Rheumatology

Background:

• Adult dermatomyositis is associated with cancer in up to 25% of cases.
• No definitive clinical, histologic, or laboratory markers identify paraneoplastic dermatomyositis.
• Frequency of cutaneous features in cancer-associated dermatomyositis is underreported.

Purpose of the Study:

• To review the characteristics of paraneoplastic dermatomyositis in patients treated at a single hospital.
• To identify potential clinical and laboratory features associated with malignancy in dermatomyositis.

Main Methods:

• Retrospective review of 12 cases of paraneoplastic dermatomyositis.
• Data collected included patient demographics, associated cancers, time between diagnoses, cutaneous and muscle involvement, dysphagia, lung disease, and autoantibody levels.

Main Results:

• Mean patient age was 61 years; common cancers included ovarian and bladder.
• Cancer was diagnosed before dermatomyositis in most cases, with a mean interval of 7 months.
• Amyopathic dermatomyositis occurred in 7 patients; characteristic rashes included heliotrope and violaceous photodistributed rash. Superficial cutaneous necrosis was noted in 3 cases. Myositis-specific autoantibodies were absent in tested patients.

Conclusions:

• Paraneoplastic dermatomyositis can be amyopathic.
• No specific cutaneous markers reliably indicate malignancy in dermatomyositis.
• Myositis-specific antibodies are not linked to paraneoplastic dermatomyositis.