Paraneoplastic Cardiac Involvement in Renal Cell Carcinoma With Dermatomyositis Sine Dermatitis.

Background: Dermatomyositis is an idiopathic inflammatory myopathy that has been established as one of the many paraneoplastic phenomena. Cardiac involvement can occur with dermatomyositis but has rarely been reported in the literature because symptoms are usually subclinical.

Case Report: A 72-year-old female presented with generalized weakness for 1 month after a recent diagnosis of renal cell carcinoma. Her weakness was attributed to a myopathic process that was identified as dermatomyositis after muscle biopsy. Laboratory tests revealed persistently elevated cardiac troponin I despite the absence of cardiac symptoms and a subsequent negative ischemic workup. After administration of intravenous steroids and treatment of the underlying renal cell carcinoma, the patient's cardiac enzymes normalized, suggesting a paraneoplastic etiology of her cardiac manifestations.

Conclusion: Cardiac involvement as a paraneoplastic process is a rare entity and can present with elevated troponin as shown in our case. Its underlying mechanism has not been clearly elucidated, but this case may shed some light on a new or unknown myocardial manifestation related to malignancy.