NK-cell enteropathy: a novel indolent mimic of enteropathy-associated T-cell lymphoma. Case report with long-term follow-up
Background: Enteropathy-associated T-cell lymphoma (EATCL) is an intraepithelial lymphocyte derived small intestinal lymphoma frequently associated with celiac disease. A variant of EATCL composed of CD56+ cells apparently does not arise against the genetic background of celiac disease, but shows the same poor outcome with most patients dying within a year (1).
Case report: We report a 67-years-old patient presenting with non-specific abdominal complaints, but night sweats, fever or weight loss were absent. Endoscopy demonstrated multiple areas of mucosal erythema, erosions and small ulcers in the stomach, small and large intestine. Histology revealed a patchy mucosal infiltration by medium-sized pleomorphic lymphoid cells expressing CD3, CD56, but not CD4, CD5, and CD8 without evidence of T-cell receptor clonality by PCR, consistent with NK-cell derivation. Due to the oligosymptomatic clinical presentation a watch & wait strategy was chosen. For the next five and a half years no lymphoma-associated symptoms developed and endoscopic and histologic evaluations at regular intervals showed no evidence of progression. Recently, a publication in „Blood„ reported a small series of patients with features identical to those observed in our patient, and the authors proposed the new term „NK-cell enteropathy„ for this syndrome of as yet unknown etiology (2).
Conclusion: This case report on NK-cell enteropathy appears to be the first in Europe. As malignant disorders typically lead to therapeutic decisions with potential harmful consequences, the possibility of NK-cell enteropathy has to be considered in case of CD56+ intestinal lesions in order to avoid unnecessary (over-) treatment.
(1) Campo E, Chott A, Kinney MC, et al. Update on extranodal lymphomas. Histopathology 2006; 48: 481–504
(2) Mansoor A, Pittaluga S, Beck PL, et al. NK-cell enteropathy: a benign NK-cell lymphoproliferative disease mimicking intestinal lymphoma: clinicopathological features and follow-up in a unique case series. Blood 2011; 117: 1447–52