A unique case of an indolent CD56-positive T-cell lymphoproliferative disorder of the gastrointestinal tract: a lesion potentially misdiagnosed as natural killer/T-cell lymphoma.

Primary intestinal natural killer (NK)/T-cell lymphoma (nasal-type) and enteropathy-associated T-cell lymphoma, type II, are CD56-positive lymphoproliferative disorders with very poor survival rates. We report a long-surviving patient with a CD56-positive T-cell lymphoproliferative disorder of the gastrointestinal tract that presented as vomiting, diarrhea, weight loss, and pain. This patient was referred to the university hospital as a case of peripheral T-cell lymphoma due to this CD56-positive lymphocyte population. There was no evidence of enteropathy; and the infiltrates were negative for CD8, Epstein-Barr virus, and T-cell receptor gene rearrangement. Despite its persistence for 8 years, the clinical course has remained indolent. This report confirms that patients may rarely present with a CD56-positive NK/T-cell-like proliferation of the gastrointestinal tract, yet follow an indolent clinical course. Thus, all pathologic features of enteropathy-associated T-cell lymphoma or NK/T-cell lymphoma should be present before making this diagnosis and exposing the patient to toxic chemotherapy.