Case Presentation: A 54-year-old Japanese man presented to his primary care physician with a 3-month history of epigastric pain, fever, and unintentional weight loss. Upper endoscopy showed only a gastric polyp. Abdominal computed tomography showed small intestinal dilatation accompanied by adhesion to the sigmoid colon, and perianal abscess. Crohn’s disease was suspected and he was referred to our hospital for further evaluation. At presentation, vital signs were within normal limits. Physical examination was notable for lower abdominal tenderness. Laboratory data showed 155 U/mL lactate dehydrogenase, 978 U/mL soluble interleukin-2 receptor, and 9.5 U/mL thymidine kinase . Colonoscopy showed no abnormalities. Small bowel series revealed segmental small intestinal dilatation. We performed double-balloon endoscopy (DBE) to evaluate the jejunum and ileum. DBE showed a dilated jejunal segment with distal stenosis. There was a sharply demarcated ulcerated jejunal tumor with well-circumscribed granular mucosa. These gross findings were consistent with primary intestinal lymphoma; thus, we obtained a mucosal specimen from the lesion. Biopsy revealed malignant T cells positive for CD8, granzyme B and TIA-1, confirming diagnosis of enteropathy-associated T-cell lymphoma (EATL). Bone marrow evaluation was positive for lymphoma cells. The clinical course was complicated by small bowel obstruction, for which urgent tumor resection was performed. The patient subsequently started chemotherapy with CHOP.

Discussion: Most primary gastrointestinal lymphoma is B-cell lineage, and T-cell lymphoma is rare. The most common symptoms are abdominal pain, fever, and weight loss. Diagnosis of EATL can be delayed because lesions are most frequently found in the small intestine and symptoms are not specific. In our case, DBE and pathological examination led to final diagnosis. EATL is classified into type I and II. The latter type is more common in Asians , who have lower incidence of celiac disease. Type II has a high risk of intestinal perforation and obstruction, as in our case, and is now called monomorphic epitheliotropic intestinal TCL (MEITL) because of its morphological features. MEITL tends to be complicated by perianal abscess, and thus is often difficult to distinguish from Crohn’s disease. Consequently, we should actively suspect MEITL when a patient presents with B symptoms. The standard therapy is not yet established, although CHOP is most frequently administered, with an anticipated 5-year survival rate of 19.7%. While the prognosis of MEITL is still poor, new therapeutic approaches and research offer hope for improved prognosis. In fact, our case experienced recurrence after six cycles of CHOP, and currently requires third-line therapy with HDAC inhibitor .

Conclusions: EATL should be one of the differential diagnoses if a patient has intestinal ulcerous lesions with B symptoms.