Extranodal NK/T-cell lymphoma, nasal type presenting as primary intestinal lymphoma vs intestinal T-cell lymphoma: A borderline diagnostic category in the revised WHO classification

Extranodal NK/T-cell lymphoma, nasal type, is an unusual Epstein-Barr Virus (EBV)-related lymphoma that carries a poor prognosis. Most cases affect upper aerodigestive tract, and secondarily may extend to skin, lungs, testis, and other sites. Extranodal NK/T-cell lymphoma, nasal type, presenting primarily as intestinal lymphoma is rare, and not recognized as a distinct entity and neither is considered as a special subtype of intestinal lymphoma of T-cell lineage. Here, we describe a 36-year-woman who presented with abdominal pain and acute-onset diarrhea. Her clinical course was complicated by intestinal perforation and peritonitis. She died one month later of sepsis. Pathologic examination revealed extranodal NK/T-cell lymphoma, nasal type, confined to the intestine. Immunophenotypically, the neoplastic cells expressed CD3 and Granzyme B, and were positive for EBV-encoded RNA (EBER) by in situ hybridization. From the practical point of view, we highlight the clinical, pathologic and immunophenotypic features that can be useful in the differential diagnosis from other intestinal lymphomas of T-cell lineage.