A Rare Localization of a Neuroendocrine Tumor

Abstract

A 58-yr-old man presented with multiple hepatic lesions found during a diagnostic evaluation for unintentional weight loss. Needle biopsy indicated a well-differentiated neuroendocrine tumor with a low proliferation index ( 2%). The patient denied flush or diarrhea, and the clinical investigation revealed no signs of heart failure. Biochemically increased levels of chromogranin A (1335.6 g/liter; reference, 19.4–98.1) and urinary 5-hydroxy indoleacetic acid (156 mol/liter/24 h; reference, 47) were found. Somatostatin receptor scintigraphy revealed a strong enhancement of the known liver lesions but no further uptake in the gastrointestinal or pulmonary area. However, a strongly positive lesion emerged in projection of the left atrium (Fig. 1A). Echocardiographically, this lesion translated into a solid tumor of 3 cm within the left atrium (Fig. 1B). Ventricular function was normal, without evidence of carcinoid heart disease. Surgical extraction was performed (Fig. 1C), and histologically the cardiac tumor consisted of neuroendocrine tissue with an identical immunohistochemical profile to the hepatic lesions and a similarly low proliferation index. Neuroendocrine tumors can arise in various locations (1), and the cardiac sequelae of increased levels of serotonin are well known (2). Although several reports have described tumors located within the myoand pericardium (3, 4), a tumor arising within the left atrium has not been reported so far. Based on the present findings and despite extensive immunohistochemical evaluation, it cannot be determined whether the cardiac lesion represents the primary tumor or a metastasis. Interestingly, the patient reported removal of a pulmonary tumor more than 40 yr ago in Turkey, indicating the possibility of a primary neuroendocrine tumor in the pulmonary system. Unfortunately, the corresponding medical documents could no longer be located.