A 72-year-old female was referred to our hospital after having experienced fever and abdominal pain for 5 days and a skin rash for 3 days before admission. She also complained of polyarthralgia, predominantly on her distal extremities. At admission, her body temperature was 38.8 C and she had a skin rash composed of exudative maculopapules and erythema multiforme over most of her body. Based on a consultation with a dermatologist who made a tentative diagnosis, we suspended loxoprofen and famotidine, medications she had been taking, because of the suspicion that the eruptions may have been drug-induced. Concomitantly, she received antibiotic therapy (meropenem) under adequate hydration, and underwent repeated blood and stool cultures. Laboratory data showed systemic inflammatory response represented by an increased WBC, 7380/muL, and moderately elevated CRP, 7.74 mg/dL. Her computed tomography (CT) scan demonstrated thickening of mucosa and enlarged mesenteric lymph nodes (Figure 1). A colonoscopy examination showed a round mucosal elevation with hemorrhagic erosion and ulceration at the terminal ileum and cecum (Figure 2), for which the pathological finding was suspicious malignant lymphoma with an infiltration of atypical lymphocytes into necrotic mucosa (Figure 3). Immunohistochemistry determined CD3+ T-cell distribution in the submucosal tissue, but did not confirm clonality of lymphocytes. Based on the pathology results, we performed an 18-fluoro-deoxyglucose positron emission tomography (FDG-PET)/CT scan, which drew an accumulation of FDG isotopes into regional mesenteric lymph nodes (SUV max 2.6). In addition, an increased level of soluble interleukin-2 receptor (sIL-2R), 3095 IU/mL, and an expansion of a lymphocyte subset expressing gammadelta T-cell receptor in peripheral blood and bone marrow (10.9% and 3.9%, respectively) supported the diagnosis of malignant lymphoma. These results led to a tentative diagnosis of enteropathy-associated T-cell lymphoma (EATL, or gammadeltaT-cell lymphoma). The patient's febrile and abdominal symptoms ameliorated rapidly a few days after antibiotics were initiated, and her skin eruptions improved over the following 7 days.
Since we could not obtain a confirmation of the pathological diagnosis, we reevaluated all aberrant clinical findings after the remission of the patient's symptoms. Within the 2-week treatment course, her laboratory data recovered to normal ranges. The sIL-2R level decreased to 483 IU/mL, and gammadelta T cells in peripheral blood were almost nonexistent (0.04%). A CT scan and colonoscopy conducted a few weeks after onset revealed slight swelling of the mesenteric lymph nodes and completely normal mucosa. During the second evaluation of the tentative diagnosis, Yersinia pseudotuberculosis was identified from her stool culture at admission. In light of all of the findings, we made the final diagnosis of Yersinia enterocolitis.