Indolent NK-Cell Lymphoproliferative Disorder of the Gastrointestinal Tract - a Report of two Cases of a new Provisional Entity on the World Health Organization Classification of Hematolymphoid Tumors.

Indolent NK-cell lymphoproliferative disorder of the gastrointestinal tract is a new provisional entity listed in the structure of the forthcoming fifth edition of the World Health Organization (WHO) Classification of Hematolymphoid Tumors. It was first named as "NK-cell enteropathy" and "Lymphomatoid gastropathy" by two independent series a decade ago. Molecular or cytogenetic studies have lent support to the clonal/neoplastic nature of this entity. Herein we add two of such cases that still challenge pathologists and were previously diagnosed as aggressive lymphomas of NK/T derivation.