NK cell enteropathy: a case report with 10 years of indolent clinical behaviour

Aims Natural killer (NK) cell enteropathy is a recently described clinically indolent condition characterised by atypical NK cell infiltrates in the gastrointestinal mucosa that mimics malignant lymphoma. We report a case that highlights the indolent clinical behaviour by documenting absence of clinical progression over 10 years. Methods and results We report the case of a 69‐year old female who had clinically long‐standing abdominal pain and recurrent mucosal ulcerations associated with atypical NK cell infiltrates. The clinical, morphologic and immunophenotypical findings in this case were diagnostic of NK cell enteropathy. Review of the patient's prior biopsies demonstrated that this persisted without clinical progression for 10 years, confirming the clinical indolent course. Conclusion Recognition of NK cell enteropathy is important to avoid over‐diagnosing this benign condition as an aggressive lymphoma.