Atypical Carcinoid Syndrome in a Patient Presenting With Pericarditis and Supraventricular Tachycardia: A Case Report

Atypical carcinoids are more uncommon than typical carcinoids, and carcinoid syndrome in general is quite rare. Mediastinal atypical carcinoid is a rare neuroendocrine tumor (NET) that spreads aggressively and rapidly. Morphologically, neuroendocrine tumors are classified into typical carcinoid, atypical carcinoid, small cell carcinoma, and large cell neuroendocrine carcinoma, and the latter two are high-grade tumors. The incidence of atypical carcinoid is rare, and the prognosis is poor, which makes larger trials difficult. It may affect the liver, lungs, or mediastinum with or without metastasis. We present a case of a 47-year-old male patient who presented with chest pain and was found to be in supraventricular tachycardia (SVT) on initial presentation to the hospital. A repeat electrocardiogram (ECG) showed widespread ST-segment elevation. A bedside echocardiogram showed a moderate pericardial effusion, and the patient underwent a coronary angiogram, which showed normal coronary arteries. A computed tomography pulmonary angiogram (CTPA) showed a right mediastinal mass, and the patient was referred to oncology following a discussion in a multidisciplinary team (MDT) meeting. He was commenced on neoadjuvant chemotherapy and has been followed up since in the outpatient clinic. This case is unique due to the initial presentation of supraventricular tachycardia and pericardial effusion.