Eva Kusmirek, MD; John D. Grizzard, MD; Kathryn M. Olsen, MD

KEY FACTS

Terminology
Imaging

TERMINOLOGY

Synonyms
- Pseudomasses
Definitions
- Entities that appear as masses on initial imaging (usually echo) but often are either normal structures or clinically insignificant variant lesions; usually resolved with cross-sectional imaging (CT or MR)
  - Normal cardiac variants
    - Crista terminalis
      - Normal fibromuscular ridge indenting right atrium (RA)
      - Demarcates site of fusion of embryologic primitive RA with sinus venosus
    - Eustachian valve
      - Variably prominent ridge of tissue at junction of inferior vena cava (IVC) with RA
      - Directs blood flow toward foramen ovale in fetal life
      - When prominent, can be mistaken for mass on echo
    - Other congenital remnants of valve of sinus venosus in RA
      - Thebesian valve: At junction of coronary sinus with RA
      - Chiari network: Net-like structure though to be variant of eustachian valve but much more mobile
    - Taenia sagittalis
      - Most prominent pectinate muscle in RA
      - Remnant of septum spurium
    - Coumadin (warfarin) ridge
      - Band-like structure in left atrium (LA), between left superior pulmonary vein and left atrial appendage (LAA)
      - Described as Q-tip sign on transesophageal echocardiography (TEE)
      - Mistaken for thrombus or mass in echocardiography
  - Intracardiac benign abnormalities
    - Lipomatous hypertrophy of interatrial septum (LHIAS)
      - Hyperplasia of normal fat cells often contiguous with epicardial fat
      - Fat infiltrates interatrial septum and expands it to diameter > 2 cm but spares fossa ovalis, creating dumbbell shape
      - May be hot on FDG PET due to composition of brown fat, which is FDG avid
    - Mitral annular calcification (MAC)
      - Calcification of fibrous annulus of mitral valve usually occurs as degenerative change
      - Occurs earlier and is more extensive in renal failure
      - May appear mass-like in some cases, especially if caseous MAC
    - Sinus of Valsalva aneurysm
      - Abnormal enlargement of single sinus, usually right (~ 80%)
      - Usually congenital in origin, less commonly due to endocarditis
    - Membranous septal aneurysm associated with ventricular septal defect (VSD)
      - Redundant septal tissue arising adjacent to membranous VSD that may appear mass-like
      - May partially occlude VSD
    - Hypertrophic cardiomyopathy (asymmetric variant)
  - Extracardiac lesions: Less common causes of confusion on imaging
    - Hiatal hernia
    - Complex/loculated pericardial effusion or prominent pericardial fat
  - Thrombus
    - Actually mass, not pseudomass, but not neoplasm

IMAGING

General Features
MR Findings
CT Findings
Imaging Recommendations

DIFFERENTIAL DIAGNOSIS

PATHOLOGY

Staging, Grading, & Classification

CLINICAL ISSUES

Presentation

DIAGNOSTIC CHECKLIST

Consider
Image Interpretation Pearls

Selected References

Tumma R et al: Evaluation of cardiac masses by CMR-strengths and pitfalls: a tertiary center experience. Int J Cardiovasc Imaging. 32(6):913-20, 2016
Terpenning S et al: Imaging pitfalls, normal anatomy, and anatomical variants that can simulate disease on cardiac imaging as demonstrated on multidetector computed tomography. Acta Radiol Short Rep. 4(1):2047981614562443, 2015
Anavekar NS et al: Computed tomography of cardiac pseudotumors and neoplasms. Radiol Clin North Am. 48(4):799-816, 2010
Weinsaft JW et al: Detection of left ventricular thrombus by delayed-enhancement cardiovascular magnetic resonance prevalence and markers in patients with systolic dysfunction. J Am Coll Cardiol. 52(2):148-57, 2008
Salanitri JC et al: Cardiac lipoma and lipomatous hypertrophy of the interatrial septum: cardiac magnetic resonance imaging findings. J Comput Assist Tomogr. 28(6):852-6, 2004
Meier RA et al: MRI of right atrial pseudomass: is it really a diagnostic problem? J Comput Assist Tomogr. 18(3):398-401, 1994
Mirowitz SA et al: Fibromuscular elements of the right atrium: pseudomass at MR imaging. Radiology. 182(1):231-3, 1992

Related Anatomy

Related Differential Diagnoses

References

Tables

KEY FACTS

Terminology
Imaging

TERMINOLOGY

Synonyms
- Pseudomasses
Definitions
- Entities that appear as masses on initial imaging (usually echo) but often are either normal structures or clinically insignificant variant lesions; usually resolved with cross-sectional imaging (CT or MR)
  - Normal cardiac variants
    - Crista terminalis
      - Normal fibromuscular ridge indenting right atrium (RA)
      - Demarcates site of fusion of embryologic primitive RA with sinus venosus
    - Eustachian valve
      - Variably prominent ridge of tissue at junction of inferior vena cava (IVC) with RA
      - Directs blood flow toward foramen ovale in fetal life
      - When prominent, can be mistaken for mass on echo
    - Other congenital remnants of valve of sinus venosus in RA
      - Thebesian valve: At junction of coronary sinus with RA
      - Chiari network: Net-like structure though to be variant of eustachian valve but much more mobile
    - Taenia sagittalis
      - Most prominent pectinate muscle in RA
      - Remnant of septum spurium
    - Coumadin (warfarin) ridge
      - Band-like structure in left atrium (LA), between left superior pulmonary vein and left atrial appendage (LAA)
      - Described as Q-tip sign on transesophageal echocardiography (TEE)
      - Mistaken for thrombus or mass in echocardiography
  - Intracardiac benign abnormalities
    - Lipomatous hypertrophy of interatrial septum (LHIAS)
      - Hyperplasia of normal fat cells often contiguous with epicardial fat
      - Fat infiltrates interatrial septum and expands it to diameter > 2 cm but spares fossa ovalis, creating dumbbell shape
      - May be hot on FDG PET due to composition of brown fat, which is FDG avid
    - Mitral annular calcification (MAC)
      - Calcification of fibrous annulus of mitral valve usually occurs as degenerative change
      - Occurs earlier and is more extensive in renal failure
      - May appear mass-like in some cases, especially if caseous MAC
    - Sinus of Valsalva aneurysm
      - Abnormal enlargement of single sinus, usually right (~ 80%)
      - Usually congenital in origin, less commonly due to endocarditis
    - Membranous septal aneurysm associated with ventricular septal defect (VSD)
      - Redundant septal tissue arising adjacent to membranous VSD that may appear mass-like
      - May partially occlude VSD
    - Hypertrophic cardiomyopathy (asymmetric variant)
  - Extracardiac lesions: Less common causes of confusion on imaging
    - Hiatal hernia
    - Complex/loculated pericardial effusion or prominent pericardial fat
  - Thrombus
    - Actually mass, not pseudomass, but not neoplasm

IMAGING

General Features
MR Findings
CT Findings
Imaging Recommendations

DIFFERENTIAL DIAGNOSIS

PATHOLOGY

Staging, Grading, & Classification

CLINICAL ISSUES

Presentation

DIAGNOSTIC CHECKLIST

Consider
Image Interpretation Pearls

Selected References

Tumma R et al: Evaluation of cardiac masses by CMR-strengths and pitfalls: a tertiary center experience. Int J Cardiovasc Imaging. 32(6):913-20, 2016
Terpenning S et al: Imaging pitfalls, normal anatomy, and anatomical variants that can simulate disease on cardiac imaging as demonstrated on multidetector computed tomography. Acta Radiol Short Rep. 4(1):2047981614562443, 2015
Anavekar NS et al: Computed tomography of cardiac pseudotumors and neoplasms. Radiol Clin North Am. 48(4):799-816, 2010
Weinsaft JW et al: Detection of left ventricular thrombus by delayed-enhancement cardiovascular magnetic resonance prevalence and markers in patients with systolic dysfunction. J Am Coll Cardiol. 52(2):148-57, 2008
Salanitri JC et al: Cardiac lipoma and lipomatous hypertrophy of the interatrial septum: cardiac magnetic resonance imaging findings. J Comput Assist Tomogr. 28(6):852-6, 2004
Meier RA et al: MRI of right atrial pseudomass: is it really a diagnostic problem? J Comput Assist Tomogr. 18(3):398-401, 1994
Mirowitz SA et al: Fibromuscular elements of the right atrium: pseudomass at MR imaging. Radiology. 182(1):231-3, 1992

KEY FACTS

Terminology

Imaging

TERMINOLOGY

Synonyms

Definitions

IMAGING

General Features

MR Findings

CT Findings

Imaging Recommendations

DIFFERENTIAL DIAGNOSIS

PATHOLOGY

Staging, Grading, & Classification

CLINICAL ISSUES

Presentation

DIAGNOSTIC CHECKLIST

Consider

Image Interpretation Pearls

Selected References

Tables

KEY FACTS

Terminology

Imaging

TERMINOLOGY

Synonyms

Definitions

IMAGING

General Features

MR Findings

CT Findings

Imaging Recommendations

DIFFERENTIAL DIAGNOSIS

PATHOLOGY

Staging, Grading, & Classification

CLINICAL ISSUES

Presentation

DIAGNOSTIC CHECKLIST

Consider

Image Interpretation Pearls

Selected References