key: cord-0878202-9phmf9ra authors: Gandhi, Parth S.; Queen, Russell; Stowens, Justin; Nomura, Jason T. title: Soft tissue mass adjacent to the heart date: 2020-08-20 journal: Vis J Emerg Med DOI: 10.1016/j.visj.2020.100861 sha: 720cc8b128492b361bb58cceb1cdd96bf7657335 doc_id: 878202 cord_uid: 9phmf9ra nan A 45-year-old male with a history of hyperlipidemia presented to the Emergency Department complaining of a 2-week history of intermittent dizziness attributed by the patient to anxiety related to persisting psychosocial stressors. The episodes of dizziness were occurring more frequently; on the day of presentation an episode occurred while seated. The dizziness was associated with palpitations and tachypnea. He complained of some mild watery diarrhea but denied any chest pain, headache, photophobia, nausea, vomiting, extremity swelling, rash, dysuria, hematuria, or recent travelling. The patient endorsed tobacco use but denied alcohol or illicit drug use. Patient denied any prior history of similar symptoms. The patient was recently tested for SARS-CoV-2 and was reported negative. Upon presentation to the ED vital signs showed heart rate 96 beats per minute, blood pressure of 165/102 mm Hg, respiratory rate of 20 breaths per minute, temperature of 36.7 C, and a SpO2 97% on room air. The patient's physical exam was unremarkable and specifically no rhythm irregularity, murmurs, rubs, or gallops were noted on cardiac examination. Laboratory studies including CBC, BMP, Troponin, TSH, and D-Dimer, were within the normal ranges except for sodium of 135 mmol/L and WBC count of 10.9/nl. The patient's EKG was normal sinus rhythm with a ventricular rate of 72. A chest X-ray showed an enlarged cardiac silhouette, see Fig. 1 . Due to the reported symptoms and abnormal CXR the decision was made to perform a bedside echocardiogram to evaluate for potential pericardial effusion. The bedside echocardiogram showed no pericardial effusion; there was a pericardial fat pad present. Additionally there was a layer of soft tissue outside of the pericardial sac. This was noted in all views of the heart but clearest in the parasternal long axis. To obtain better resolution and imaging of the soft tissue a curved array probe in an abdominal preset was utilized, see Fig. 2 , Video supplement 1. Due to large soft tissue mass external to the pericardial sac a CT of the chest was performed for further evaluation with concern for potential mediastinal mass. The CT images revealed bilateral prominent paracadial fat pads without necrosis or inflammatory changes, see Fig. 3 . There is normally some adipose tissue in the cardiophrenic space, between the pericardium, diaphragm and visceral pleura. In this case the paracardial fat was larger than usual, measured over 30 mm, causing the abnormal findings on echocardiogram. The patient was discharged for primary care follow-up regarding his intermittent symptoms that were unrelated to the abnormal imaging studies. Pericardial and paracardial fat pads are typically an incidental finding that is present in a large proportion of the general population and is of little significance and measures less than 5 mm. Normally, fat tissue will surround coronaries and the apex of the heart, however T when a large amount of circumferential pericardial and/or paracardial fat is identified, a number of possible etiologies must be considered. R. Pruente et al. described lesions based on their location in and around the heart. 1 For example, a large lesion in the cardiophrenic (i.e. between the heart and diaphragm) space can possibly originate through a diaphragmatic defect. This specific herniation of fat tissue is referred to as a Morgagni hernia; however, due to its relationship with structural malformation, it is typically identified in the pediatric population. There is a 10-15% risk of strangulation of the contents and therefore must be addressed promptly in symptomatic patients. 2 Cystic lesions may also develop in the cardiophrenic space and are largely a benign, incidental finding. Typically, cysts are identified on imaging as having well-defined borders without any solid, soft tissue components or inflammatory changes. If, however, a cystic lesion is identified as having possible soft-tissue components, a malignant process along with fat tissue necrosis must be considered in the differential. Often in this scenario, lymphomas, lymphosarcoma, and disseminated metastases from distant primary tumors can be the source. 3 Identification of a soft tissue mass outside of the pericardial sac may also warrant further investigation and in this instance the 4 T's of the anterior mediastinal masses need to be considered and these include metastatic lymphadenopathy, thymomas, teratomas and thyroid masses. A thymolipoma is a tumor containing fat tissue that originates in the thymus. This is often confused with another fat containing tumor known as a teratoma. Usually, teratomas are benign, will have a fluid/ cystic component, and will not have an anatomic connection to the thymic bed. Pericardial and paracardial fat pads do not need any immediate intervention and can simply be monitored on an outpatient basis once a thorough differential is explored. It is appropriate to pursue ultrasound, CT imaging, and even MRI imaging to appropriately characterize such lesions especially in the setting of suspicious findings such as inflammatory changes, stranding, and heterogeneous make-up. A 4-year-old boy, with a history of reflux, presents to the emergency department with his parents for concerns of increased work of breathing over the last 2 h. The parents state that he has been complaining of mid-epigastric pain all morning after eating breakfast and is now having difficulty taking a deep breath in. A chest X-ray is performed and reveals a fat containing soft tissue structure above the diaphragm with linear opacities. What is the most likely diagnosis? a) Pericardial fat necrosis b) Morgagni hernia c) Enlarged lymph node d) Thymoma e) Lymphoma Although pericardial fat necrosis may also appear as a fat containing soft tissue structure, the question mentions that there were linear opacities identified. The opacities correspond to omental vessels which therefore would lend evidence to a diaphragmatic through which omental fat has herniated and now may be in danger of incarceration and/or strangulation. 3 Often you may even see loops of bowel but the absence of these does not necessarily exclude hernia as a differential as it may just be omentum herniating through. A 48-year-old female patient, with a history of rheumatoid arthritis, obesity, and CHF, presents to the emergency department with complaints of a mild, nonproductive cough for the past 3 weeks. Patient denies any other accompanying symptoms. She is on daily corticosteroid therapy as well as Lasix 40 mg daily. A chest x-ray is performed and an incidental finding of excessive, nonencapsulated fat is noted in the anterior mediastinum. What is the most likely diagnosis for this incidental finding? Mediastinal lipomatosis usually forms in the anterior mediastium of obese patients and patients who are on steroid therapy. The question did not make any mention of heterogeneity of the fat which would typically be seen in a liposarcoma. Futhermore, liposarcomas will usually arise in the posterior mediastinum. Teratomas and thymolipoma need to be considered for anterior mediastinal masses, however in teratomas there is usually a cystic component and thymolipomas are often associated with Myasthenia Gravis. There was no mention of the thymic gland either, which points away from this diagnosis as well. 1 Fatty lesions in and around the heart: a pictorial review Right cardiophrenic angle mass Lesions of the cardiophrenic space: findings at cross-sectional imaging Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.visj.2020.100861.