Sir, We wish to report briefly on a case of cardiac lipoma—the unexpected finding of an autopsy on the body of a 50-year-old woman who suffered from atrial fibrillation. Using morphological findings and close histopathological study, we were able to explain this apparently “functional” symptom as the effect of early autonomous cardiac plexus infiltration. Cardiac lipoma is a benign neoplasm that occurs at a low rate and is currently well documented in the literature [4, 5, 8]. The original lesion generally develops at the pericardial surface or within the cardiac chambers, in the form of an encapsulated adipose mass that takes the parietal pericardium and occasionally expands over the rest of the heart. The affliction is apparent by non-specific symptoms, but quite often it is not and the diagnosis is instrumental. In the case under our observation, we were faced with a 50-year-old woman, admitted to the Universit Cattolica del Sacro Cuore Internal Medicine department with severe dyspnea and orthopnea symptoms. Suffering from atrial fibrillation since 1999, she had been administered beta-blockers for the last few years. Despite this, her recent electrocardiogram revealed atrial fibrillation at high ventricular frequency. The very night she was hospitalized, the patient passed away suddenly, and it was therefore impossible to carry out echocardiography or any other imaging method that could lead to a clinical diagnosis. At the necroscopy, a massive pulmonary embolism was identified as the ultimate cause of death. We observed clear-cut cardiac hypertrophy with in-toto dilatation of the heart, more pronounced in the right sector. Here, we found a well-encapsulated, globular, lobulated yellow mass, with a diameter of 5 cm (Fig. 1A). The mass protruded from the lateral wall of the right atrium and the superior vena cava right atrial junction. Microscopic examination of this mass showed proliferation of mature fat cells with large, clear, empty cytoplasm and eccentrically placed nuclei. Myocardial fibers and cells of the sinoatrial (SA) node (Fig. 1B) were interspersed within fat cells. Searching for the presence of nervous tissue, we focused on a careful morphological study of ganglionic structures pertaining to the atrial plexus (Fig. 2). The microscopic evidence of nervous structures trapped in the neoplasm clearly emerged from this study. In retrospect, this case epitomized for us the challenging situation of a cardiac lipoma with apparently “functional” symptoms that eventually turned out to have a very “organic” cause. Currently, cardiac lipomas are occasional findings of postmortem heart dissection. Reece et al. described 71 benign cardiac tumors, 3 of which were classified as lipomas [8]. McAllister et al. estimated that lipomas can represent approximately 8.4% of all primary cardiac Vincenzo Arena and Fabio De Giorgio contributed equally to this work.