SESSION TITLE: Student/Resident Case Report Poster - Genetic and Developmental Disorders SESSION TYPE: Student/Resident Case Report Poster PRESENTED ON: Tuesday, October 25, 2016 at 01:30 PM - 02:30 PM INTRODUCTION: Myocardial fatty foci (MFF) are benign computed tomographic (CT) findings that have recently been described in 50-64% of patients with tuberous sclerosis complex (TSC) [1,2]. MFF have distinguishing features on CT, including their well-circumscribed shape, left ventricular (LV) predominance, unique fat attenuation, and absence of invasive behavior [2]. These findings, however, have not been well described on transthoracic echocardiography (TTE). CASE PRESENTATION: A 43-year-old male with end stage renal disease (ESRD) secondary to bilateral renal angiomyolipomas from TSC presented with a linear hyper echoic left ventricular (LV) apical mass on TTE, concerning for thrombus. He was referred for a TTE as part of a pre-operative work-up for renal transplant. TTE demonstrated a LV apical hyper echoic mass in the presence of normal LV systolic function with an ejection fraction of 55%, mild LV hypertrophy, and no wall motion abnormalities [Figure 1]. These findings were further evaluated by cardiac gated CT, which showed a large area of fat deposition (-63.42 Hownsfield Units (HU)) in the apical septum corresponding to the reported muscle on echocardiography. In addition, multiple other focal areas of fat deposition were seen in the LV myocardial wall [Figure 2]. DISCUSSION: The most common causes of a LV apical mass on TTE include an LV thrombus and false tendons. However, there was no evidence of wall motional abnormality, no history of recent myocardial infarction (MI), and no history of valvular dysfunction or arrhythmia, making a thrombus less likely. Due to patient’s history of TSC, there was also concern for a cardiac rhabdomyoma, which is one of the major clinical features of TSC. In fact, 50% of patients with cardiac rhabdomyomas have a diagnosis of TSC. Cardiac rhabdomyomas are less likely in this patient, as they more commonly occur in children, are typically seen in the right ventricle or atrium, and are more invasive [3]. MFF, however, are benign, well-circumscribed round or linear deposits with unique fatty attenuation (demonstrated by -63.42 HU) and are more commonly present in the left ventricular wall [1,2]. CONCLUSIONS: Myocardial fatty foci are now being considered as part of the diagnostic spectrum for TSC in adult patients. Our case illustrates a unique presentation of MFF as a LV apical mass on TTE. Further characterization of these findings on TTE and cardiac gated CT can clinically distinguish MFF from more pathological findings and aid in the diagnosis of TSC. Reference #1: [1] Adriaensen M, Schaefer-Prokop C; Duyndam D et al. Fatty Foci in the Myocardium in Patients with Tuberous Sclerosis Complex: Common Finding at CT. Radiology 2009; 253(2): 359-363. Reference #2: [2] Tresoldi S, Munari A, Leo GD, Pompili G, et al. Myocardial Fatty Foci in Adult Patients with Tuberous Sclerosis Complex: Association with Gene Mutation and Multiorgan Involvement Reference #3: [3] Watson GH. Cardiac rhabdomyomas in tuberous sclerosis; Ann N Y Acad Sci 1991; 615: 50-57 DISCLOSURE: The following authors have nothing to disclose: Tarun Ramayya, Amudhan Jyothidasan, William Bates, Jayanth Keshavamurthy, Gyanendra Sharma No Product/Research Disclosure Information