Gastroenterologist Tucson, AZ - Mesquite Gastroenterology and Surgery Center At Mesquite Gastroenterology and Surgery Center our priority is to deliver quality care to informed patients in a comfortable and convenient setting. Mesquite Gastroenterology and Surgery Center (MGSC) was founded in 2009 by Dr. Miguel A Arenas.Office Staff‧Make an Appointment‧Patient Forms‧Surgery Center‧Contact Us‧Procedures.