Diagnostic challenge presented by extranodal NK/T cell lymphoma expressing CD20, CD30 and CD15: A case report.

The atypical expression of immune phenotypes in lymphoma is often associated with a poor prognosis and presents diagnostic challenges. The present study reports on a rare extranodal NK/T cell lymphoma. In addition to typical morphology and immunohistochemical characteristics, these tumors strongly express CD20 and CD30 and partially express CD15, which is associated with aggressive clinical behavior. Differential diagnosis should be cautiously approached in extranodal NK/T cell lymphoma because the abovementioned markers are typically expressed in B cell lymphoma or Hodgkin's lymphoma. In addition to rigorous histological and comprehensive immunohistochemical staining, whole-body imaging and molecular testing can assist with diagnosis. In the present case, the patient died of multiple organ failure shortly after diagnosis. Lymphoma exhibits an atypical immunophenotype, thus emphasizing the importance of a thorough analysis of the interrelations among clinical, imaging and pathological features.