Complete Heart Block and Cardiac Tamponade Secondary to Merkel Cell Carcinoma Cardiac Metastases

Abstract

This is a unique case of Merkel cell carcinoma, a rare neuroendocrine tumor, metastasizing to the heart and inducing a progression of cardiac complications such as new-onset atrial fibrillation, malignant pericardial effusion with tamponade physiology, first-degree heart block, and complete heart block. Metastases to the heart are relatively rare but should be suspected if a patient with a known neoplasm presents with new cardiac manifestations. This is the first case report of cardiac metastases from Merkel cell carcinoma causing cardiac tamponade or complete heart block. This case highlights the clinical decision-making involved in managing cardiac tamponade and complete heart block in the setting of metastatic disease to the heart.

Management and Prognosis of Cardiac Metastatic Merkel Cell Carcinoma: A Case–Control Study and Literature Review

“…Contrary to what was observed in the autopsy series, all patients in our cohort had endocardium lesions. Both within our series and previously reported cases, the predominance of endocardial lesions involved in the right side of the heart supports the hypothesis that cardiac mMCC disseminates via hematogenous spread [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. The predilection of the right atrium/ventricle may be a characteristic feature of cardiac metastasis in MCC.…”

“…There were 14 unique patients with cardiac mMCC reported in the published case reports between 1990 to 2019 ( Table 4 ) [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. The median age at diagnosis was 67.5 years (range 23–82 years) with a male predominance (male 9, female 5).…”

“…MCC metastasis to the heart is rare, with experience limited to isolated case reports [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Before the era of immunotherapy, the prognosis of metastatic MCC (mMCC) was limited to months [ 9 ].…”

Merkel Cell Carcinoma Metastatic to the Heart

“…5 Cardiac metastases from all tumors are relatively common, and autopsy series show a range of 8% to 12%. 10,11,12 There are no randomized controlled trials for the management of Merkel cell carcinoma. 8 Extramedullary plasmacytoma of the heart is rare, and few cases have been reported in the literature.…”

Metastatic Merkel Cell Carcinoma Masquerading as Multiple Immune-Related Adverse Events

“…While infrequent overall, since 2001, many cases of cardiac metastasis of MCC have been reported in the literature, with clinical consequences including symptoms of chest pain and shortness of breath, various degrees of heart block, and malignant pericardial effusion with resultant tamponade [ 28 – 33 ]. With an additional complication of acute kidney injury, the scattered cardiac metastases observed on autopsy probably drove the acute hypertroponinemia observed in this patient's case, as has been observed in other head and neck cancers metastatic to the heart.…”