Indolent T-cell lymphoproliferative disorder almost always presents with significant GI tract severe symptoms (chronic diarrhea, weight loss, abdominal pain, and/or GI bleeding); involves multiple lesions, most commonly located in the small intestine, colon, and, rarely, stomach, esophagus, and oral cavity; exhibits lesions that resemble those of NKCE and LG but involve infiltrations of T-cells that unlike the NK cells of NKCE and LG, are slowly proliferating, homogenously small-sized, CD56-negative, usually express CD4 and CD8, are not infected by the Epstein-Barr virus, are clonal in nature based on their T-cell receptor rearrangements, and, while located primarily in the lamina propria, may infiltrate into nearby submucosal tissue.Other diseases which NKCE and LG may superficially resemble and require consideration as being in their differential diagnoses include: peripheral T-cell lymphoma not otherwise specified, T cell lymphomas that consist of mature T cells and occur in the GI tact, MALT lymphoma of the stomach, and other types of stomach lymphomas. Treatment
Patients with NKCE or LG should be treated for symptom relief but, as currently recommended, not for the underlying NK cell proliferative disease. Regular follow-ups that include repeated endoscopic analyses of their GI tracts and tests for the spreading of the disease to other organs are recommended to insure the original diagnosis is correct. Prognosis
NKCE and LG usually follow a persistent or regressing-relapsing coarse but uncommonly spontaneously relapses without a recurrence even in cases that have been mistreated with chemotherapy, bone marrow transplantation, or gastric resection. Patients with LG are less likely to have persistent or regressing-relapsing coarse.
Natural killer cell enteropathy, also termed  NK cell enteropathy (NKCE), and a closely related disorder, lymphomatoid gastropathy (LG), are non-malignant diseases in which one type of lymphocyte, the natural killer cell (i.e. NK cell), proliferates excessively in  the gastrointestinal tract (GI tract). This proliferation causes red, sore-like spots, raised lesions, erosions, and ulcers in the mucosal layer surrounding the GI tract lumen. Both disorders cause either no or only vague symptoms of GI tract disturbances such as nausea, vomiting, and bleeding.In 2006, a persistent but apparently benign disease that involved the proliferation of NK cells at multiple sites throughout the intestines was described. This disorder appeared similar to and easily mistaken for a highly malignant disease, extranodal NK/T-cell lymphoma, nasal type. In 2010, a similarly non-malignant disorder that involved the proliferation of NK cells in the stomach was described. The disease mimicked gastrointestinal lymphomas. Since these first descriptions, several case series and case reports have been published on these enteropathies.The two NK cell proliferation diseases have been termed NK cell enteropathy and lymphomatoid gastropathy with NKCE being seen mostly in the United States and Korea and LG being seen mostly in Japan. Besides this geographical difference, the only other critical difference between the two diseases is that the lesions in NKCE occur in the small intestine, colon, stomach, and/or esophagus while those of LG are limited to the stomach.