A case report of recurrent Merkel cell carcinoma with synchronous metastases to the heart and stomach

RATIONALE: Merkel cell carcinoma (MCC) is an aggressive, rare neuroendocrine skin cancer. MCC metastasis to the heart is exceedingly rare and gastric metastases from MCC have rarely been reported. PATIENT CONCERNS: We described the case of an 82-year-old man diagnosed with recurrent MCC with cardiac and gastric metastasis who presented with poor oral intake and severe weight loss. The patient was diagnosed with MCC 3 years ago and treated with surgical resection and radiation. INTERVENTIONS: We performed stomach biopsy in edematous lesion. And fluoroscopy and ultrasound guided biopsy of the cardiac mass was performed. DIAGNOSES: MCC with synchronous metastases to the heart and stomach. OUTCOMES: The primary lesion had complete resolution and the patient remained disease free on regular follow-up every 6 months for 2 and half years. After MCC recurred, palliative anti-cancer therapy was considered but could not be performed due to the patient's poor performance status involved elderly, combined recurrent pneumonia. LESSONS: To our best knowledge, this is the first report of synchronous cardiac and gastric metastasis from cutaneous MCC worldwide. Although uncommon, MCC should be considered in clinical cases of synchronous metastasis.