This case report describes a rare presentation of seronegative dermatomyositis primarily manifesting as severe myocarditis, reported to strengthen disease recognition and differential diagnosis.
Key Findings
Background
Seronegative dermatomyositis can present primarily with severe myocarditis, representing a rare and clinically significant manifestation.
The case involves a patient with seronegative dermatomyositis (negative autoantibodies) whose predominant presentation was severe myocarditis.
Dermatomyositis is described as a rare idiopathic inflammatory myopathy (IIM) primarily affecting skin and striated muscle.
Cardiac involvement in dermatomyositis is noted to typically be asymptomatic or subclinical, making this severe symptomatic presentation unusual.
Autoantibodies in this patient were negative (seronegative), which is notable as cardiac involvement cases are often associated with positive autoantibodies.
Background
Severe myocarditis as a complication of dermatomyositis is clinically rare but represents an important cause of mortality.
The abstract explicitly states that dermatomyositis complicated by severe myocarditis is 'clinically rare' (临床少见).
Despite its rarity, severe myocarditis in dermatomyositis is identified as 'an important cause of death' (重要死亡原因).
Cardiac involvement in dermatomyositis is described as most commonly asymptomatic or subclinical.
The case is reported specifically to improve clinical recognition and differential diagnosis of this presentation.
Conclusions
This single case report was published to provide clinical reference for improving identification and differential diagnosis of seronegative dermatomyositis with cardiac involvement.
The authors state the purpose is to 'strengthen disease cause identification and differential diagnosis' (强化病因识别和鉴别诊断).
The report involves one case (1例) of seronegative dermatomyositis with severe myocarditis.
The case is presented to 'provide clinical reference' (提供临床参考) for other clinicians.
The seronegative nature of the case adds diagnostic complexity, as autoantibody testing is commonly used in IIM diagnosis.
What This Means
This research presents a single patient case of dermatomyositis — an inflammatory disease that typically affects the skin and muscles — who unusually developed severe inflammation of the heart muscle (myocarditis) as the main symptom. What made this case particularly challenging was that the patient tested negative for the autoantibodies (proteins made by the immune system attacking the body) that are commonly used to help diagnose this condition, making it 'seronegative.' Most people with dermatomyositis who develop heart problems either have no symptoms or only mild, detectable changes, so a case with severe myocarditis as the leading feature is considered rare.
This research suggests that dermatomyositis should be considered as a possible underlying cause even when standard autoantibody blood tests come back negative and when the heart is the primary organ affected. The authors emphasize that severe myocarditis, though an uncommon complication of dermatomyositis, can be life-threatening and is an important cause of death in this disease. Recognizing this unusual presentation early may be critical for appropriate treatment.
The practical implication of this case report is that clinicians evaluating patients with unexplained severe myocarditis should consider inflammatory muscle diseases like dermatomyositis in their differential diagnosis, even in the absence of the typical skin and muscle findings or positive autoantibody results. This case adds to the medical literature on atypical presentations of dermatomyositis to help doctors recognize and diagnose similar cases in the future.
Zhang C, Li C, Liu X, Zuo H, Wang Q. (2026). [A case report of seronegative dermatomyositis primarily presenting as severe myocarditis].. Zhonghua nei ke za zhi. https://doi.org/10.3760/cma.j.cn112138-20260131-00068