What's LASH on Echocardiography

 

Differentiating Lipomatous Hypertrophy of the Interatrial Septum (LASH) from atrial tumors on echocardiography can be challenging, but here are some key features to help with the distinction. Its Fatty infiltration of the proximal and distal portions of the atrial septum, generally with sparing of the fossa ovalis, without a stalk and most commonly seen in the elderly and obese.

Characteristics of LASH on Echo:

1. Location: LASH typically involves the interatrial septum, sparing the fossa ovalis.

2. Appearance: LASH appears as a homogeneous, hyperechoic (bright) mass with a smooth, well-defined border.

3. Size: LASH can be quite large, but it typically does not exceed 2-3 cm in thickness.

4. Shape: LASH often has a characteristic "dumbbell" or "hourglass" shape, with the narrowest part at the fossa ovalis.

5. Mobility: LASH is typically fixed and does not move with the cardiac cycle.

Characteristics of Atrial Tumors on Echo

1. Location: Atrial tumors can occur anywhere in the atria, including the interatrial septum.

2. Appearance: Atrial tumors can appear as heterogeneous, hypoechoic (dark) or hyperechoic (bright) masses with irregular borders.

3. Size: Atrial tumors can vary in size, but they often grow larger than LASH.

4. Shape: Atrial tumors can have an irregular shape and may have a more complex appearance.

5. Mobility: Atrial tumors may be mobile and move with the cardiac cycle.

Key Differences

1. Location and sparing of the fossa ovalis: LASH typically spares the fossa ovalis, while atrial tumors may involve this area.

2. Homogeneity and echogenicity: LASH is typically homogeneous and hyperechoic, while atrial tumors can be heterogeneous and have varying echogenicity.

3. Size and shape: LASH is often smaller and has a more characteristic shape, while atrial tumors can be larger and more irregular.

4. Mobility: LASH is typically fixed, while atrial tumors may be mobile.

Additional Imaging Modalities

If the diagnosis is still uncertain after echocardiography, additional imaging modalities such as cardiac MRI or CT scans may be helpful in distinguishing LASH from atrial tumors. These modalities can provide more detailed information about the mass, including its composition, size, and relationship to surrounding structures.

LASH:

Lipomatous Hypertrophy of the Interatrial Septum (LASH) is a rare, non-cancerous condition where there's an excessive buildup of fat in the wall of tissue that separates the heart's upper chambers, known as the interatrial septum. This accumulation of fat can be quite significant, measuring over 2 cm in thickness. Due to its unusual appearance, LASH is often considered in the differential diagnosis for both cancerous and non-cancerous tumors that can occur in the atria. Despite its benign nature, it's essential to accurately diagnose LASH to distinguish it from other potentially more serious conditions.

The differential diagnosis for Lipomatous Hypertrophy of the Interatrial Septum (LASH) includes:

Benign Tumors

1. Atrial myxoma: A benign tumor that can occur in the atria.

2. Lipoma: A benign tumor composed of fat tissue.

3. Hemangioma: A benign tumor composed of blood vessels.

Malignant Tumors

1. Atrial sarcoma: A rare, malignant tumor that can occur in the atria.

2. Metastatic tumors: Cancer that has spread to the heart from another location.

Other Conditions

1. Thrombus: A blood clot that can form in the atria.

2. Cystic lesions: Abnormal fluid-filled structures that can occur in the heart.

3. Pericardial cysts: Abnormal fluid-filled structures that can occur in the pericardium, the sac surrounding the heart.

Accurate diagnosis is essential to distinguish LASH from these conditions.