Natural killer cell lymphoma of the small intestine: Diagnosis by flow cytometric immunophenotyping of paracentesis fluid

Natural killer (NK) cell lymphoma is a mass-forming neoplasm of putative NK cell lineage that typically appears in extranodal locations and has the fo llowing immunophenotype: CD2 positive. surface CD3 negative, cytoplasmic CD 3 positive, and CD56 positive. We report a case of small-intestinal NK cell lymphoma that was originally diagnosed as an enteropathy-associated T-cell lymphoma based on paraffin immunohistochemistry;. However subsequent flow cytometric immunophenotyping of paracentesis fluid resulted in the correct diagnosis. We describe the case to illustrate the usefulness of this techni que, which has not previously been described in such a case. (C) 1999 Wiley -Liss, Inc.