Gastroduodenal tuberculosis is a very rare location of abdominal tuberculosis; it is usually secondary to pulmonary tuberculosis and is often associated with HIV infection. We report a case of a 45-year-old woman with no HIV infection and no evidence of pulmonary tuberculosis, with a history of duodenal ulcer treated for several months, who presented at the emergency department with severe gastric outlet obstruction of recent onset caused by ulcerohypertrophic antroduodenal tuberculosis. The lesion was misdiagnosed at endoscopy as a malignancy, although histological examination of biopsies showed only chronic inflammation. The diagnosis was established at surgery, when a frozen section of an enlarged lymph node showed the presence of giant cells and caseating granuloma. The treatment was gastric resection with Roux-en-Y gastrojejunal anastomosis. In this patient the rare gastroduodenal location of tuberculosis occurred as primary disease in the absence of other organ involvement.