Primary Hodgkin lymphoma of the gastrointestinal tract is exceedingly rare to the point that some authors regard with skepticism the existence of this entity. Cases of gastrointestinal Hodgkin lymphoma have been reported previously; however, most of these cases represented secondary involvement of the digestive tract in the context of systemic disease. Other cases have been reclassified in retrospective studies as non-Hodgkin lymphomas after the application of immunohistochemical techniques. We report a case of primary Hodgkin lymphoma of the gastrointestinal tract in a patient who presented with obstructive symptoms at the site of a gastroileal bypass; the bypass had been performed years earlier because of morbid obesity. Some non-Hodgkin lymphomas may morphologically mimic Hodgkin lymphoma and vice versa; therefore, an accurate pathologic diagnosis is important, since the therapeutic approach and prognostic implications differ significantly for these diseases. In this context, immunohistochemistry should be used to confirm or to exclude the histologic diagnosis of Hodgkin lymphoma.