The atypical cellular infiltrate

distorts the glandular architecture in the early stages of the disease, whereas glandular destruction is noted in advanced disease. Nevertheless, the atypical cells rarely infiltrate glandular epithelium (absence of epitheliotropism). In addition, angiocentric or angiodestructive growth pattern, a characteristic feature noted in ENKTL, is generally not observed in NK-cell enteropathy or lymphomatoid Selleck JNK-IN-8 gastropathy (10,11). The atypical cells express NK cell markers such as CD56, cytoplasmic CD3, CD7, TIA-1 and/or Granzyme B, but are non-reactive for CD4, CD8, CD5, CD10, CD20, CD30, CD68, or CD138. The proliferative index as evident by Ki-67 nuclear staining Inhibitors,research,lifescience,medical is usually low.

Furthermore, Inhibitors,research,lifescience,medical in contrast to ENKTL, NK-cell enteropathy or lymphomatoid gastropathy is not typically associated with EBV infection (10,11). Prognosis This lesion clinically behaves in a benign and an indolent manner. Disease persistence was observed in 67% to 75% of the patients, with recurrence in one patient two years after spontaneous regression of the disease (11). Moreover, none of the patients showed evidence of disease progression, and there was no reported mortality (10,11). It Inhibitors,research,lifescience,medical is therefore essential to distinguishing this entity from the more aggressive NK/T-cell lymphomas in order to avoid unnecessary therapy and its associated risks. Other GI hematopoietic neoplasms Extramedullary plasmacytoma (EMP) Extramedullary plasmacytoma is a neoplastic proliferation of monoclonal plasma cells outside of the peripheral blood circulation and bone marrow. The tumor cells show eccentrically located nuclei with speckled Inhibitors,research,lifescience,medical chromatin. The abundant deeply basophilic cytoplasm forms a distinct, partial

perinuclear hoff or clearing. The tumor cells are arranged in large sheets or clusters. Propagation of larger, immature plasma cells (plasmablasts) as well as pleomorphism with bi-nucleated and frequently tri-nucleated Inhibitors,research,lifescience,medical forms is typically noted in advanced or more extensive disease process. The neoplastic plasma cells express plasma cell markers such as CD138 and CD38 with monotypic cytoplasmic immunoglobulin light chain (either kappa or lambda) but lacking surface immunoglobulin. Approximately 67-79% of the cases show aberrant co-expression of CD56 (69). EMP is a recognized occurrence; mafosfamide however, involvement of the GI tract, particularly colon is rare with less than 25 documented cases in the literature (13). Amyloidosis, a systemic disease associated with plasma cell dyscrasia particularly the light chain or amyloid light chain (AL) subtype, may also be encountered in the GI tract and most frequently occurs in the small bowel (14). Amyloid deposit shows characteristic dull brick red staining with Congo red and demonstrates apple-green birefringence on polarized light, features that differentiate amyloid from collagen.