Extra-nasal types of Extra-nodal natural killer cell lymphoma (ENKL) have been known with poorer prognoses than nasal type with the worst responses to treatment. The current work introduces a case of ENKL with GI involvement with no nasal manifestations. We report a 56-year male farmer with fever, productive cough, dyspnea, anorexia, vomiting and chill in addition to malaise and cachexia of three months duration referred to a hospital with acute abdominal pain, and was diagnosed as peritonitis due to perforated terminal ileum ulcer before experiencing surgery as a case of acute abdomen. The pathologic study of the relevant biopsy showed "ulceration and necrosis with dense fibrinoleukocytic exudation and granulation tissue formation. CT scan determined a bilateral mass like haziness which was more likely to be metastatic. The review of the previous pathologic specimens raised Natural Killer/T cell Lymphoma (NKTL), the reason for which we focused on the patient's sinuses and nasal area as well as nasopharynx. There was no finding in examination and endoscopy of sinuses. Pathology also found malignant high grade non-Hodgkin T cell lymphoma in specimens obtained from debridement of ulcer at terminal ileum. It also showed that most of the tumor cells were positive for CD3, CD56, CD8, and LCA but negative for CD19, CD20 and AE1/AE3. Positive reactions for CD30 were shown by some cells. CD56, CD3, and CD8 were expressed by neoplastic cells and CD30 were positive in few cells. Proliferative activity (Ki67 index) was high (60-70%). This was the main base to diagnose an extra-nodal extra-nasal NK/T cell lymphoma. In conclusion, Intestinal changes at middle age, especially in men with nonspecific clinical manifestations is highly advised to be studied pathologically and genetically for T cell types like CD30 positive T cells which are usually engaged in ENKTL.