In contrast to NKCE and LG, extranodal NK/T cell lymphoma, nasal type: is malignant and often aggressive; causes serious, persistent, and often progressive GI tract and other symptoms; commonly involves the head and neck areas and/or multiple organs outside of the GI tract; is deeply invasive, extending beyond the lamina propia of the GI tract; and consists of lesions which contain malignant Epstein-Barr virus-infected NK cells that have numerous gene mutations and chromosome abnormalities and that center around and destroy blood vessels. Monomorphic epitheliotropic intestinal T cell lymphoma (MEITL): MEITL is a malignant and extremely aggressive GI tract disease. It is manifested by serious, sometimes life-threatening GI tract symptoms such as GI tract obstructions and perforations; is usually localized to the small intestine but may involve other areas of the GI tact; is invasive, e.g. spreads to the submucosa; commonly metastasizes to GI tract lymph nodes; and is composed of lesions which contain Epstein-Barr virus-negative homogenously appearing, medium-sized, malignant T cells that may have mutations or other genetic abnormalities in their STAT5B, JAK3, TP53, SETD2, BRAF, KRAS, GNA12, CREBBP, and/or Myc genes. Indolent T cell lymphoproliferative disorder of the gastrointestinal tract: This recently described disease, while generally considered benign, has in rare cases been lethal with disease spreading to the bone marrow and blood. This disease is a potentially precancerous condition.
Symptoms of the disease usually remain vague and mild. == References ==