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Recurrent Cardiogenic Syncope From Extrinsic Organ Anomaly

      Case Presentation

      A 40-year-old woman presented with recurrent syncope. She reported multiple (>20) episodes of non-prodromal loss of consciousness, periodically provoked by physical exertion. One episode resulted in a nasal fracture due to the abrupt nature of her syncope. The characterization of each episode was inconsistent with a neurogenic seizure. Other causes of syncope (vasovagal, situational, carotid hypersensitivity, and orthostasis) were also deemed unlikely. On physical examination, a low-pitched, brief adventitious sound was appreciated after each S2 sound in the right lower sternal border. The remainder of the physical examination was unremarkable. Initial workup, including complete blood count, comprehensive metabolic panel, cardiac enzymes, and ECG yielded normal results. The chest radiograph did not show any gross cardiac or pulmonary parenchymal pathologic condition (Fig 1). Telemetry did not demonstrate any malignant arrhythmias, and video-guided EEG did not document any seizure activity.
      A transthoracic echocardiogram was subsequently obtained and demonstrated a freely mobile, homogenously-echogenic mass, measuring 3.4 x 2.6 cm, within the right atrium (RA). The structural integrity of the tricuspid valve was not compromised. The remainder of the transthoracic echocardiogram demonstrated normal biventricular chamber size and systolic function. Transesophageal echocardiography confirmed the mass within the RA. It intermittently occluded the tricuspid valve and resulted in transient “ball valve” obstruction of blood flow (Fig 2). It appeared to originate from the inferior vena cava (IVC) and was not adherent to the RA, interatrial septum, or tricuspid valve.
      Figure thumbnail gr2
      Figure 2A, Mass occupies the right atrium and obstructs the tricuspid inflow in this mid-esophageal view by transesophageal echocardiography. B, Mass in the right atrium extends from the inferior vena cava as demonstrated in the bicaval view by transesophageal echocardiography.
      What is the diagnosis?
      Diagnosis: Accessory hepatic lobe within the right atrium.
      Based on available data, atrial myxoma, primary or metastatic cancer, and thromboembolism were considered. Cardiovascular magnetic resonance (CMR) imaging demonstrated a large, encapsulated, noninfiltrating mass (3.0 × 2.1 cm) within the RA. The mass was homogenous in appearance without a central fibrous scar. It was pedunculated with its stalk originating from the main body of the liver and traversing the IVC (Fig 3F). The stalk was contiguous with the hepatic vein. The remaining structures were deemed normal without overt congenital defects detected. The tissue characteristics of the mass were identical to the adjacent liver parenchyma (Fig 3A-E). A diagnosis of an accessory hepatic lobe (AHL) within the RA was made.
      Figure thumbnail gr3
      Figure 3A-F, Cardiovascular magnetic resonance tissue characterization of accessory hepatic lobe compared with myocardium. A, Isointense on steady-state free precession imaging. B, Isointense on T2-weighted imaging. C, Isointense on early gadolinium enhancement. D, Low signal intensity on late gadolinium enhancement. E, Contrast uptake on first-pass perfusion imaging correlates with hepatic perfusion. F, Sagittal imaging clearly shows attachment of accessory hepatic lobe to liver.
      Given the clinical context of recurrent syncope, surgery was performed. A 4.0 × 2.5 × 2.5-cm specimen was resected successfully (Fig 4A). Histopathologic analysis was consistent with typical liver parenchyma encapsulated by fibrous tissue (Glisson’s capsule) (Fig 4B-C). A central fibrous scar was not detected. The stalk measured 0.5 × 0.9 cm and contained biliary ductal and hepatic vascular elements without evidence for cholestasis.
      Figure thumbnail gr4
      Figure 4A, Resected specimen, measuring 4.0 × 2.5 × 2.5 cm. Histopathology of resected specimen shows B, liver parenchyma with portal triad and C, fibrovascular stalk with biliary and vascular elements.
      The postoperative course was unremarkable. On follow up, there has been no recurrence of syncope. Repeat CMR performed 6 months later demonstrated complete surgical resection of the mass with no evidence for recurrence (Fig 5).
      Figure thumbnail gr5
      Figure 5Postsurgical cardiovascular magnetic resonance shows complete resection of accessory hepatic lobe without residual mass on corresponding steady-state free precession images. A, Axial four-chamber view as compared with A; B, sagittal view as compared with F.

      Discussion

       AHL

      AHL is a rare congenital anatomic malformation characterized by accessory hepatic tissue attached to the main body of the liver.
      • Lin H.
      • Chen C.
      • Kong M.
      Accessory lobe of the liver in a 14-year-old girl.
      Ectopic liver lobes, in contrast, maintain no such connection with the main body of the liver.
      • Yeh B.
      • Hudson A.J.
      • Reoma J.L.
      • Popa C.
      • Andersen J J.
      • Lichtenberger J J.
      Intracardiac heterotopic liver presenting as a right atrial myxoma: a case report.
      AHL typically develops in the infrahepatic region, below the diaphragm.
      • Wang C.
      • Cheng L.
      • Zhang Z.
      • et al.
      Accessory lobes of the liver: a report of 3 cases and review of the literature.
      As a result, most patients are asymptomatic, and detection is predominantly incidental.
      • Glenisson M.
      • Salloum C.
      • Lim C.
      • et al.
      Accessory liver lobes: Anatomic description and clinical implications..
      This report describes a rare case of recurrent cardiogenic syncope due to an AHL located within the RA.
      There are only six other reported cases of this particular type of AHL.
      • Yeh B.
      • Hudson A.J.
      • Reoma J.L.
      • Popa C.
      • Andersen J J.
      • Lichtenberger J J.
      Intracardiac heterotopic liver presenting as a right atrial myxoma: a case report.
      ,
      • Chapman-Fredricks J.
      • Birusingh R.
      • Ricci M.
      • Rodriguez M.
      Intracaval liver with cardiac extension: a new developmental anomaly?.
      • Trocciola S.M.
      • Balsam L.B.
      • Yee H.
      • Gianos E.
      • Srichai M.B.
      • DeAnda A.
      Ectopic liver: an unexpected finding in a right atrial mass.
      • Xu L.
      • Jeudy J.
      • Burke A.P.
      Ectopic hepatic tissue presenting as right atrial mass.
      • Forest S.J.
      • Kaplan K.C.
      • Michler R.E.
      Accessory liver in the right atrium: a rare cause of syncope.
      • Soliman M.
      • Akanbi O.
      • Salem A.
      • Khreis M.
      • Abdel-Latif A.
      Ectopic liver tissue mistakenly diagnosed as a right atrial myxoma.
      Patient ages have ranged from 12 years
      • Chapman-Fredricks J.
      • Birusingh R.
      • Ricci M.
      • Rodriguez M.
      Intracaval liver with cardiac extension: a new developmental anomaly?.
      to 69 years.
      • Forest S.J.
      • Kaplan K.C.
      • Michler R.E.
      Accessory liver in the right atrium: a rare cause of syncope.
      There was modest female preponderance in this population (female, 67%
      • Yeh B.
      • Hudson A.J.
      • Reoma J.L.
      • Popa C.
      • Andersen J J.
      • Lichtenberger J J.
      Intracardiac heterotopic liver presenting as a right atrial myxoma: a case report.
      ,
      • Trocciola S.M.
      • Balsam L.B.
      • Yee H.
      • Gianos E.
      • Srichai M.B.
      • DeAnda A.
      Ectopic liver: an unexpected finding in a right atrial mass.
      ,
      • Xu L.
      • Jeudy J.
      • Burke A.P.
      Ectopic hepatic tissue presenting as right atrial mass.
      ,
      • Soliman M.
      • Akanbi O.
      • Salem A.
      • Khreis M.
      • Abdel-Latif A.
      Ectopic liver tissue mistakenly diagnosed as a right atrial myxoma.
      ; male, 33%
      • Chapman-Fredricks J.
      • Birusingh R.
      • Ricci M.
      • Rodriguez M.
      Intracaval liver with cardiac extension: a new developmental anomaly?.
      ,
      • Forest S.J.
      • Kaplan K.C.
      • Michler R.E.
      Accessory liver in the right atrium: a rare cause of syncope.
      ). Forest et al
      • Forest S.J.
      • Kaplan K.C.
      • Michler R.E.
      Accessory liver in the right atrium: a rare cause of syncope.
      reported the largest AHL with a maximum diameter of 3 cm. At a maximum diameter of 4 cm, the case described herein represents the largest AHL reported to date.
      Prior publications have not described characteristic physical examination findings for an AHL within the RA. This report postulates that a “tumor plop,” as was detected in this case, may be auscultated during physical examination due to a mechanism comparable with an atrial myxoma.

       Role of Imaging

      Multimodality imaging played an instrumental role in diagnosing this rare anomaly. Echocardiography permitted prompt mass detection and cursory anatomic characterization. CMR was critical in (1) anatomic localization, (2) assessment for myocardial infiltration, (3) detection of attachment to the liver via a stalk, (4) tissue characterization to exclude malignancy, and (5) assessment of other cardiac structures and adjacent organs.
      CMR is emerging as a mainstay diagnostic tool for the evaluation of cardiac masses. Basic protocols delineate mass size, location, and border. Additional sequences perform complementary roles: fast spin-echo and steady-state free precession sequences establish basic anatomic location; steady-state free precession cine sequences allow assessment of mobile masses due to its high spatial resolution; T2-weighted imaging allows for assessment of edema. With gadolinium-enhanced CMR imaging, vascularity and fibrosis can be demonstrated.
      CMR imaging was instrumental in elucidating the diagnosis of AHL and facilitating surgical planning.

       Surgical Approach

      The mass was excised with the use of a standard sternotomy approach. After direct aortic artery cannulation, the femoral vein (short 25F) and superior vena cava (24F angled cannula) were cannulated. The patient was cooled to 25° C, and the heart was arrested with the use of antegrade cardioplegia. Right oblique atriotomy was performed after circulatory arrest. The pedunculated mass was visualized extending from the IVC. The base of the stalk was tied with a heavy silk that was used for retraction. The base was ligated flush with the IVC with a pledgeted 4-0 Prolene suture (Ethicon Inc). The stalk was amputated with a harmonic scalpel, and the stump was cauterized. Care was taken to confirm absence of leakage of bile or blood.

       Pathology

      Histopathologic analysis was performed to confirm the diagnosis. It demonstrated benign hepatic parenchyma, with hepatocytes and portal triad elements, encapsulated by a fibrous tissue (Fig 4B). The associated stalk encased both venous and biliary ductal elements further affirming the diagnosis. AHL can be distinguished from a focal nodular hyperplasia by the absence of a central fibrous scar containing blood vessels.
      • Rosai J.
      Rosai and Ackerman’s Surgical Pathology.
      In contrast, AHL histologically consists of normal liver parenchyma.

      Conclusion

      • This report adds to the current literature the largest AHL detected within the RA. It demonstrates that an AHL can present as an intracardiac mass and can result in recurrent cardiogenic syncope. Knowledge of this rare condition lifts the barrier to its early diagnosis.
      • CMR can be used to establish the diagnosis and guide patient care. In the contemporary armamentarium of multimodality imaging, CMR differentiates itself from other imaging modalities by its superior ability to noninvasively perform tissue characterization of cardiac masses and comprehensively assess the heart and its neighboring structures.
      • With the present tools available in today’s clinical practice, detection of an intracardiac mass is not sufficient to proceed with surgical resection; rather, a comprehensive preoperative investigation must be the standard of care.
        • Xu L.
        • Jeudy J.
        • Burke A.P.
        Ectopic hepatic tissue presenting as right atrial mass.

      Acknowledgments

      Financial/nonfinancial disclosures: None declared.
      Other contributions: CHEST worked with the authors to ensure that the Journal policies on patient consent to report information were met.

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