LAUSR

To the Editor, Enterocolic lymphocytic phlebitis (ELP) is a phlebitis that occurs predominantly in the right colon to ileum without systemic vasculitis and is mainly seen in older persons. Segmental and circumferential enterocolic stenosis with erosions and ulcers is seen with intestinal involvement of ELP. Lymphocytic colitis (LC) is one form of microscopic colitis that is common in Europe and the United States, but rare in Japan. However, in recent years, its incidence has been increasing worldwide, including in Japan. The colonic mucosa of LC appears normal or mildly abnormal endoscopically. Chronic watery diarrhea without bleeding is a major symptom of LC. Since the coexistence of ELP and LC is unusual, the first case of ELP in association with LC in Japan is described. The patient was an 81‐year‐old, 60 kg man with a history of prostatic cancer, type 2 diabetes mellitus, and chronic renal failure. His chief complaints were watery diarrhea that appeared five to six times a day and weight loss of approximately 7 kg. He underwent blood tests, upper and lower gastrointestinal endoscopies, and stool culture tests. Endoscopically, the whole mucosa of the large intestine was rough and bled easily. No special findings, such as active inflammation or ulcers, were observed. A colon random biopsy was also performed, but the definite cause of the watery stool could not be determined. Two months later, he was admitted to the hospital because of acute‐onset fever and abdominal pain. Strangulation of the ileus was suspected on computed tomography examination, and emergency surgery was performed. At surgery, there was no strangulated ileus, but changes in the mucosal color of the peripheral ileum were found. The ileocecal region, 80 cm of ileum and 25 cm of cecum, was resected. In the specimen of the resected intestines, phlebitis was observed in vessels of diameter of about 50–1900 μm in submucosa, muscularis propria, subserosa and mesentery (Figure 1a), but no inflammation was observed in the accompanying arteries (Figure 1b). Vasculitis of capillaries in mucosa could not be assessed due to severe ischemic changes. The vessel walls were infiltrated with eosinophils, neutrophils, lymphocytes, and histiocytes. Fibrinoid necrosis was seen in affected vessels of various sizes from subserosa to mesentery (Figure 1c). Granulomatous vasculitis with multinucleated giant cells was also found in affected veins of diameter of about 100–200 μm in submucosa (Figure 1c). In the ileum showing changes in mucosal color, obstructive thrombus was observed in veins of submucosa, subserosa and mesentery, and the mucosa was extensively necrotic with ischemic changes. Of the lymphocytes infiltrating the vessel wall, T‐cells were dominant, including both CD4 and CD8‐positive cells (Figure 1d). Congo red staining was performed to differentiate from amyloidosis, and it was negative. Therefore, a diagnosis of ELP was made. The first case of ELP was reported by Stevens et al. in 1976, and the term ELP was first used by Saraga and Costa in 1986. Intestinal vasculitis without systemic vasculitis including ELP is uncommon compared to gastrointestinal manifestations of systemic vasculitis, and it is frequently associated with inflammatory bowel disease such as Crohn's disease. Vasculitis localized only in veins is also rare. ELP is characterized histologically by ischemic necrosis due to phlebitis and severe lymphocyte infiltration into the intestinal venous wall. Arteries are not normally affected. In intestines with ELP, the majority of infiltrating lymphocytes are T cells. As seen in the present case, necrosis and granuloma were frequently reported as histological characteristics of ELP. It was discussed that granulomatous phlebitis in ELP is related to immunologic reaction to material absorbed from the bowel lumen. The presence of venous thrombi was also reported as a histological feature of ELP. In the present case, occlusion of vessels by endothelial and myointimal hyperplasia was not found, but obstructive thrombi were found in the necrotic region. The pathogenesis of the disease is not yet known, but it has been suggested that the use of some drugs, such as hydroxyethylrutoside and the antiandrogen drug flutamide, is associated with this disease. Although surgical resection of the intestines with ELP was thought to be curative without recurrence, the