a. Mallory-Weiss syndrome has linear lacerations at the gastro esophageal junction that are produced by severe prolonged vomiting;the most common cause is acute alcohol ingestion and/or chronic alcoholism. Mallory-Weiss syndrome presents with hematemesis; it can be rarely complicated by esophageal rupture (Boerhaave syndrome).
b. Esophageal varices are dilated submucosal veins in the lower third of the esophagus, usually secondary to portal hypertension. The most common cause is cirrhosis. Clinically, the presentation is asymptomatic, though there is massive hematemesis when the varices are ruptured. Complications include potentially fatal hemorrhage. Treatment is generally with band ligation, sclerotherapy, or balloon tamponade.
In a Nutshell Mallory-Weiss tears vs. esophageal varices:
Although both are associated with alcohol abuse and can present with hematemesis, Mallory-Weiss tears typically occur acutely as a result of retching/vomiting. Esophageal varices result from portal hypertension and will usually present with a more significant bleeding episode.