The interaction of lipomatous hypertrophy of the interatrial septum with pericardial adipose tissue biomarkers by computed tomography.

OBJECTIVE: Novel pericardial adipose tissue imaging biomarkers are currently under investigation for cardiovascular risk stratification. However, a specific compartment of the epicardial adipose tissue (EAT), lipomatous hypertrophy of the interatrial septum (LHIS), is included in the pericardial fat volume (PCFV) quantification software. Our aim was to evaluate LHIS by computed tomography angiography (CTA), to elaborate differences to other pericardial adipose tissue components (EAT) and paracardial adipose tissue (PAT), and to compare CT with [18F]FDG-PET. MATERIALS AND METHODS: Of 6983 patients screened who underwent coronary CTA for clinical indications, 190 patients with LHIS were finally included (age 62.8 years ± 9.6, 31.6% females, BMI 28.5 kg/cm2 ± 4.7) in our retrospective cohort study. CT images were quantified for LHIS, EAT, and PAT density (HU), and total PCFV, with and without LHIS, was calculated. CT was compared with [18F]FDG-PET if available. RESULTS: CT-density of LHIS was higher (- 22.4 HU ± 22.8) than all other pericardial adipose tissue components: EAT right and left (97.4 HU ± 13 and - 95.1 HU ± 13) PAT right and left (- 107.5 HU ± 13.4 and - 106.3 HU ± 14.5) and PCFV density -83.3 HU ± 5.6 (p < 0.001). There was a mild association between LHIS and PAT right (Beta 0.338, p = 0.006, 95% CI: 0.098-577) and PAT left (Beta 0.249, p = 0.030; 95% CI: 0.024-0.474) but not EAT right (p = 0.325) and left (p = 0.351), and not with total PCFV density (p = 0.164). The segmented LHIS volume comprised 3.01% of the total PCFV, and 4.3% (range, 2.16-11.7%) in those with LHIS > 9 mm. [18F]FDG-PET: LHIS was tracer uptake positive in 83.3% (37.5%: mild and 45.8%: minimal) of 24 patients. CONCLUSIONS: LHIS is a distinct compartment of PCFV with higher density suggesting brown fat and has no consistent association with EAT, but rather with PAT. CLINICAL RELEVANCE STATEMENT: LHIS should be recognized as a distinct compartment of the EAT, when using EAT for cardiovascular risk stratification. KEY POINTS: LHIS is currently included in EAT quantification software. LHIS density is relatively high, it is not associated with EAT, and has a high [18F]FDG-PET positive rate suggesting brown fat. LHIS is a distinct compartment of the EAT, and it may act differently as an imaging biomarker for cardiovascular risk stratification.

Importance of Multimodality Cardiac Imaging in the Diagnosis of Lipomatous Hypertrophy of the Interatrial Septum-A View beyond Standard Situations.

Lipomatous hypertrophy of the interatrial septum (LHIAS) represents a benign proliferation of lipoid cells at the level of the interatrial septum (IAS) inducing an important thickening of this structure. It respects the fossa ovalis (FO) region, having a typical "hourglass" echocardiographic appearance. There are certain cases though, with unusual appearances and/or with associated pathologies that may induce similar lesions in the heart, in which the differential diagnosis cannot be guaranteed using only the standard methods. The final diagnosis has important implications in these patients' treatment plan. In this paper, we present an unusual case of a female patient undergoing chemotherapy for lung carcinoma, suspected of right atrial thrombosis/metastasis. As the diagnosis was unclear after transthoracic echocardiography (TTE), inducing the suspicion of an IAS mass with atrial wall infiltration, bi- and tridimensional transesophageal echocardiography (TOE) was performed, revealing a severely and homogenously hypertrophied IAS respecting the FO, but lacking a clear visualization of the atrial wall. The diagnosis of LHIAS was established by cardiac magnetic resonance (CMR) that certified the adipose nature of the structure, excluding the need for invasive investigations and/or treatment options. Multimodality imaging is very important for the clinician in adopting the best management plan for each individual patient.

Visceral adiposity in patients with lipomatous hypertrophy of the interatrial septum.

Lipomatous hypertrophy of the interatrial septum (LHIS) is a benign cardiac mass determined by abnormal deposition of adipose tissue in the interatrial septum. The quantitative relationship between LHIS and visceral adiposity has not been explored to date.In this retrospective study, three groups of consecutive patients undergoing CT imaging were enrolled: L + with LHIS, L- without LHIS, and LO- without both LHIS and history of malignancies. Areas of total adipose tissue (TAT), visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) and LHIS areas were calculated on CT images. The relationship between LHIS and abdominal fat distribution was investigated with linear regression models. Bonferroni correction was applied to account for multiple testing. Statistical significance was set at 5%. In this study we enrolled a total of 175 subjects: 58 (33.14%) with LHIS (L +), 51(29.14%) without LHIS (L-) and 66 (37.71%) without both LHIS and medical history of malignancies (LO-). VAT (coeff: 105.82; 95% CI 59.37-152.27), SAT (coeff: 74.59; 95% CI 31.63-117.54), and TAT (coeff: 190.37; 95% CI 115.02-265.72), were significantly higher in L + patients. Moreover, VAT (coeff: 24.95; 95% CI 6.94-42.96) and TAT (coeff: 36.58; 95% CI 8.75-64.41) were statistically significant linear predictors for LHIS area. Here, we report a novel association between LHIS and visceral adiposity using a quantitative CT-based imaging approach. The results are of great importance also because they might drive early identification of subjects with LHIS at risk for visceral obesity, and trigger lifestyle interventions aimed at weight loss.

Uncommon Incidental Diagnosis of Lipomatous Hypertrophy of the Interatrial Septum.

Lipomatous hypertrophy of the interatrial septum (LHIS) is a benign non-neoplastic cardiac lesion that previously has not been readily described, but with the increasing usage of computed tomography and echocardiography, this is now becoming a more well-characterized incidental finding. This case highlights an incidental finding of LHIS while a patient was undergoing treatment for a routine gastrointestinal bleed.

Myocardial metastasis within lipomatous hypertrophy of the interatrial septum.

A 74-year-old lady with lipomatous hypertrophy of the interatrial septum presented with symptomatic anemia. Imaging revealed a new diagnosis of metastatic cancer of presumed lung origin, with a new soft tissue myocardial lesion adjacent to the right atrium within the region of lipomatous hypertrophy. This was favored to represent a myocardial metastasis within concurrent lipomatous hypertrophy of the interatrial septum.

Double trouble during the left atrial appendage occlusion procedure.

Percutaneous structural interventions are being performed at increased numbers and rare findings or complications occur more frequently. Lipomatous hypertrophy of the interatrial septum (LHIS) is a relatively uncommon finding on transthoracic echocardiogram (TTE). The major challenge is the difficulty in performing transseptal puncture. We aimed to report the difficulties that were experienced during the left atrial appendage (LAA) closure in a case with an extreme form of LHIS.

A Confounder in the Study of a Patient With Infective Endocarditis.

Positron emission tomography (18FDG PET-CT) is a widely used method to help in the diagnosis of infective endocarditis (IE). Lipomatous hypertrophy of the interatrial septum (LHIS) is an uncommon fat deposition in the region of the interatrial septum. PET-CT images of LHIS may be indistinguishable from changes associated with IE.

A rare case of cardiac tumor of the interventricular septum complicated with atrioventricular block.

Lipomatous hypertrophy of the interatrial septum is a rare benign condition characterized by adipocyte hyperplasia with fat infiltration between the myocardial fibers in the interatrial septum. Although lipomatous hypertrophy does not occur only in the interatrial septum, its location in the interventricular septum is extremely rare. A 45-year-old woman with no medical or family history of cardiac disease presented with an episode of syncope. Transthoracic echocardiography revealed an echogenic mass in the interventricular septum and no outflow obstruction. The mass-like area showed fat tissue-specific features on computed tomography and magnetic resonance imaging, and furthermore, it showed late gadolinium enhancement. We diagnosed it as lipomatous hypertrophy of the interventricular septum. An implantable loop recorder documented paroxysmal complete atrioventricular block with presyncope. A permanent dual-chamber pacemaker was implanted. This is the first reported case of lipomatous hypertrophy of the interventricular septum treated with a pacemaker for complete atrioventricular block with syncope. We have described the case and the treatment strategy in detail. Learning objective: To understand lipomatous hypertrophy, a rare disorder, and its characteristics and differences between lipomatous hypertrophy and cardiac adipose tumors on computed tomography and magnetic resonance imaging. To learn about the appropriate treatment and clinical management of this benign condition and treat symptomatic patients.

Transseptal Puncture Through an Interatrial Septum With Lipomatous Hypertrophy: A False Perception of Success and Failure.

Transseptal puncture is a standard procedure to access the left atrium during catheter ablation of arrhythmias. It is associated with high success and a meager complication rate in the contemporary era. The potential complications of transseptal puncture include aortic puncture, perforation of the right/left atrial free wall resulting in pericardial effusion/tamponade, and systemic thromboembolism. The dissection of the interatrial septum (IAS) is a rare complication of transseptal puncture, reported in less than 1% of the procedures. We report a case of a dissection of the IAS during an attempted transseptal puncture in a 72-year-old man with lipomatous hypertrophy of the interatrial septum.

Invasive Metastatic Well-Differentiated Liposarcoma to the Heart, Found in Intraoperative Transesophageal Echocardiography.

Hematogenous metastasis of liposarcoma to the heart is rare, even though other types of distant metastatic cardiac tumors are relatively more common than primary cardiac tumors. We experienced a case of distant metastasis of liposarcoma to the right interatrial septum, mimicking lipomatous hypertrophy in transesophageal echocardiography (TEE). There were no significant findings in the preoperative transthoracic echocardiography (TTE) or computed tomography (CT). TEE was the only tool to suspect the presence of a cardiac tumor. It also helped evaluate the spread of tumor invasion and make a decision for operation.

18F-FDG PET/CT helps rule out malignancy in lipomatous hypertrophy of the interatrial septum with atypical MRI manifestations, to avoid unnecessary surgical treatment.

Lipomatous hypertrophy of the interatrial septum (LHIS) is a rare benign heart disease characterized by excessive deposition of adipose tissue in the atrial septum with sparing fossa ovalis, which demonstrates a characteristic hourglass/dumbbell configuration. We reported a case of LHIS with inhomogenous characteristic on CMR and persistently no FDG uptake on 18F-FDG PET-CT, which is contrary to a few previous cases. This single case report suggests that in case LHIS present in-homogenous characteristic on CMR, metabolic PET imaging could be used as a complementary imaging model to decrease the concern of lipomatous neoplasms, thereby avoid unnecessary surgical therapy.

Imaging Findings of Lipomatous Hypertrophy of the Interventricular Septum: A Case Report.

Primary cardiac tumors are rare. We report a case of lipomatous hypertrophy of the interventricular septum in a healthy, asymptomatic, 16 year old female, diagnosed initially by echocardiogram. Non contrast Computed tomography (CT) and Cardiac magnetic resonance imaging (CMR) were also performed to confirm the diagnosis of this rarely reported condition. Lipomatous hypertrophy of the interventricular septum is a rare form of benign cardiac tumor characterized by the proliferation of adipose tissue (fat) in the interventricular septum. This clinical entity has to be differentiated from cardiac lipoma which is a benign, encapsulated tumor. CMR helps is differentiating between the 2 conditions. As the lesion was neither causing compression of the ventricle nor obstruction to blood flow, she was managed conservatively and advised follow up.

Right atrial mass in a patient with COVID-19 pneumonia: A case report.

Lipomatous hypertrophy of the interatrial septum can have an atypical appearance by transthoracic echocardiography. The authors emphasize on the importance of the multimodality imaging approach to reach the appropriate diagnosis in such cases.

Right atrial mass-multimodality imaging-Massive lipomatous hypertrophy of the atrial septum.

Asymptomatic cardiac masses are often diagnosed incidentally. Massive lipomatous hypertrophy can be confused for other cardiac masses and need careful evaluation including multimodality imaging to manage appropriately.

Tale of fat and fib - cardiac lipoma managed with radiofrequency ablation: A case report.

BACKGROUND: Cardiac lipoma and lipomatous hypertrophy of interatrial septum (LHIS) are very rare disorders with distinct pathological features. While cardiac lipoma is a well-circumscribed encapsulated tumor of mature adipocytes, LHIS is due to entrapment of fat cells in the interatrial septum during embryogenesis. Although a biopsy is the definitive diagnostic test, these disorders can be differentiated by a cardiac magnetic resonance imaging (MRI). Treatment of LHIS is not warranted in asymptomatic patients. In symptomatic patients, surgical resection is the only recommended treatment, which has shown to improve good long-term prognosis. CASE SUMMARY: A 63-year-old Caucasian woman with past medical history significant for hypertension, hypothyroidism, right breast ductal cell carcinoma treated with mastectomy and breast implant, platelet granule disorder, asthma requiring chronic intermittent prednisone use, presented to the outpatient cardiology office with recent onset exertional dyspnea, palpitations, weight gain and weakness. Initial workup with electrocardiogram and holter monitor did not reveal significant findings. During the subsequent hospitalization for community acquired pneumonia, the patient developed symptomatic paroxysmal atrial fibrillation. Transthoracic echocardiogram showed a right ventricular mass. A biopsy was not pursued given the high risk of bleeding due to platelet granule disorder. Cardiac MRI showed characteristic features consistent with cardiac lipoma and LHIS. Prednisone was discontinued. Genetic testing for arrhythmogenic right ventricular dysplasia and 24-h urine cortisol test was negative. As multiple attempts at rhythm control failed with sotalol and flecainide, pulmonary vein isolation and right atrial isthmus radiofrequency ablation were done. She is in follow-up with symptomatic relief and no recurrence of atrial fibrillation for 10 mo. CONCLUSION: Benign fatty lesions in heart include solitary lipoma, lipomatous infiltration and lipomatous hypertrophy of interatrial septum. Although transvenous biopsy provides a definitive diagnosis, Cardiac MRI is superior to computed tomography and aids in differentiating benign from malignant lesions. Surgical excision of cardiac lipoma along with capsule and pedicle removal generally prevents recurrence, but with our patient's unusual tumor features and comorbidities proscribed a surgical approach. Symptom management with antiarrhythmics and ablation techniques were successfully utilized.

Lipomatous hypertrophy of the interventricular septum.

BACKGROUND AND AIMS: Lipomatous hypertrophy of the interatrial septum is an uncommon type of cardiac adipose tumor. It is extremely rare for these lesions to be located in the interventricular septum. METHODS: We report this case of incidentally diagnosed lipomatous hypertrophy of the interventricular septum with right ventricular outflow obstruction which caused minimal symptoms and Wolff-Parkinson-White pattern on EKG. CONCLUSION: We also discuss the diagnosis and management of this condition.

Multimodality imaging of tumefactive lipomatous hypertrophy of the right ventricle extending to the right ventricular outflow tract.

Lipomatous hypertrophy of the right ventricle is a rare entity that is usually asymptomatic and diagnosed incidentally in an otherwise healthy individual. Accurate diagnosis and assessment of possible hemodynamic consequences of this pathology is, however, necessary to secure an appropriate treatment. Multimodality imaging with echocardiography, CT, and cardiac MR can provide useful functional and anatomic information that can help to reach this goal.

Lipomatous Hypertrophy of the Interatrial Septum Manifesting as Third Degree Atrioventricular Block.

A 55-year-old patient was found to have complete heart block during preoperative assessment. Cardiac magnetic resonance imaging revealed an interatrial mass suggestive of primary cardiac tumor. Extensive evaluation including intracardiac biopsy and finally open resection revealed lipomatous hypertrophy masquerading as tumor. (Level of Difficulty: Intermediate.).

Massive labial lipomatous hypertrophy in familial partial lipodystrophy seen on computed tomographic angiography.

We present a 28-year-old female with a rare familial partial lipodystrophy. Originally presenting at the age of 14, she began experiencing hypertrophy of the fat in the mons pubis and labia majora regions. By the age of 24 she had disfiguring hypertrophy of these areas with severe fatty overgrowth, similar in nature to that experienced by her father and paternal grandmother. During her workup and planning for suction lipectomy, she underwent computed tomography angiography with the imaging manifestation of severe massive subcutaneous fat hypertrophy; the imaging appearance was only able to be explained after a thorough review of the patient's history and medical literature.

Atypical presentation of lipomatous hypertrophy of the interatrial septum: a case report.

BACKGROUND: Lipomatous hypertrophy of the interatrial septum (LHIAS) is a common finding on transthoracic echocardiogram (TTE). Occasionally, the appearance of LHIAS is atypical and multimodality imaging is helpful to make the diagnosis. We present a case of atypical LHIAS to highlight the potential aetiologies for an interatrial septal mass and review features on multimodality imaging that help decrease uncertainty and establish a diagnosis. CASE SUMMARY: A 64-year-old man with a history of hypertension, diabetes mellitus, and coronary artery disease with multiple percutaneous coronary interventions presented to the emergency room with chest pain. Transthoracic echocardiogram showed a homogenous echo-dense, intracardiac mass present within the interatrial septum. Computed tomography (CT) angiogram of the chest showed a homogenous mass similar in radiodensity to extracardiac and pericardial fat. Cardiac magnetic resonance (CMR) confirmed LHIAS by homogenous signal that was nulled on fat suppression images. DISCUSSION: This case highlights that while most LHIAS has the standard 'dumbbell' appearance on TTE, there are instances where it can appear more like an adherent mass prompting a wider differential. Unenhanced CT of the heart can be used to confirm LHIAS by the presence of low attenuation values for tissue. Alternatively, CMR can be used for tissue characterization and confirmation of LHIAS. Precontrast T2/T1-weighted CMR images with steady-state free precession show high signal intensity in the area of LHIAS and produce a black/hypointense boundary effect between fat and myocardium. A multimodality approach is crucial in arriving at the appropriate diagnosis using the tissue characterization capabilities of CT and CMR.