Extranodal NK/T-cell lymphoma, nasal type extensively involving the bone marrow.

Extranodal NK/T-cell lymphoma, nasal type, is an aggressive EBV-associated lymphoma that mainly involves the nasal cavity but has also been reported to involve other extranodal sites without nasal involvement. In contrast to aggressive NK cell leukemia (a marrow-based aggressive leukemia of NK-cell origin); extensive bone marrow and blood involvement is extremely uncommon by nasal type NK/T lymphoma. We report a patient with extranodal NK/T-cell lymphoma, nasal type that developed extensive bone marrow involvement during the course of her disease with some overlapping features with aggressive NK-cell leukemia.