Chronic Venous Insufficiency (CVI): This condition is a common cause of leg edema, especially in the absence of heart disease. CVI occurs when the veins have problems returning blood from the legs to the heart due to issues like valve problems or obstruction, leading to fluid accumulation in the legs.

Deep Vein Thrombosis (DVT): Although DVT can cause acute onset of leg edema, it's also a consideration in subacute or chronic presentations, especially if there's a history of recent immobility, surgery, or cancer.
Lymphedema: This condition involves the abnormal collection of protein-rich fluid in the interstitial tissue, leading to swelling of one or more extremities. It can be primary (genetic) or secondary (due to surgery, infection, or trauma).
Nephrotic Syndrome: Characterized by heavy proteinuria, hypoalbuminemia, and edema. The edema is typically more generalized but can be prominent in the legs.
Liver Cirrhosis: Leads to fluid retention and edema, often accompanied by ascites. The edema can be significant in the legs, especially in more advanced disease.

Pulmonary Embolism: While often associated with symptoms like dyspnea and chest pain, a large pulmonary embolism can lead to increased right heart pressures, causing leg edema. It's crucial to consider this diagnosis due to its high mortality rate if untreated.
Abdominal or Pelvic Tumors: Obstruction of the inferior vena cava or pelvic lymph nodes by a tumor can cause leg edema. These conditions are less common but critical to identify due to their implications for treatment and prognosis.
Superior Vena Cava Syndrome: Although more commonly associated with upper body edema, in rare cases, it can cause leg edema if there's significant obstruction of venous return.

Fabry Disease: A genetic disorder that can lead to edema among other systemic symptoms due to the accumulation of a particular type of fat in the body's cells.
Lipedema: A chronic condition characterized by the abnormal growth of fat cells in the legs, leading to swelling and edema, often symmetric and sparing the feet.
Sarcoidosis: A disease characterized by the growth of granulomas (inflammatory cells) in various parts of the body, which can rarely cause leg edema through lymphatic or venous obstruction.