ALK-negative anaplastic large cell lymphoma (ALCL, ALK-) is a CD30+ T-cell neoplasm composed of large lymphoid cells with abundant cytoplasm and pleomorphic nuclei that lacks expression of ALK protein. We describe a c...ALK-negative anaplastic large cell lymphoma (ALCL, ALK-) is a CD30+ T-cell neoplasm composed of large lymphoid cells with abundant cytoplasm and pleomorphic nuclei that lacks expression of ALK protein. We describe a case of ALCL, ALK-with primary involvement of the rectum in a 37 year old man, where the original diagnosis was established based on a colonoscopic biopsy. T-cell lymphomas are rare in the colorectal area and besides ALCL, their differential diagnosis includes enteropathic T-cell lymphoma, peripheral T-cell lymphoma, not otherwise specified, NK/T cell lymphoma, or NK-cell enteropathy. In addition, syncytial variant of classical Hodgkin lymphoma or a pleomorphic CD30-positive diffuse large B-cell lymphoma should also be ruled out. We discuss pitfalls of the differential diagnosis and review the literature of anaplastic large cell lymphoma in the gastrointestinal tract. Correct diagnosis of ALCL in the colon is important to avoid a colorectal surgery for an assumed adenocarcinoma, and to open the possibility for lymphoma-directed chemotherapy.展开更多
文摘ALK-negative anaplastic large cell lymphoma (ALCL, ALK-) is a CD30+ T-cell neoplasm composed of large lymphoid cells with abundant cytoplasm and pleomorphic nuclei that lacks expression of ALK protein. We describe a case of ALCL, ALK-with primary involvement of the rectum in a 37 year old man, where the original diagnosis was established based on a colonoscopic biopsy. T-cell lymphomas are rare in the colorectal area and besides ALCL, their differential diagnosis includes enteropathic T-cell lymphoma, peripheral T-cell lymphoma, not otherwise specified, NK/T cell lymphoma, or NK-cell enteropathy. In addition, syncytial variant of classical Hodgkin lymphoma or a pleomorphic CD30-positive diffuse large B-cell lymphoma should also be ruled out. We discuss pitfalls of the differential diagnosis and review the literature of anaplastic large cell lymphoma in the gastrointestinal tract. Correct diagnosis of ALCL in the colon is important to avoid a colorectal surgery for an assumed adenocarcinoma, and to open the possibility for lymphoma-directed chemotherapy.
