A CD56-negative case of blastic natural killer-cell lymphoma (agranular CD4+/CD56+ haematodermic neoplasm)

Sir, Four cases of blastic natural killer (NK) cell‐lymphoma were reported in a recent issue of this Journal.1 This disease, also called agranular CD4+/CD56+ haematodermic neoplasm, represents a rare and distinct clinicopathological entity that was described recently.2 The disease is characterized by its clinical presentation (high skin tropism, bone marrow involvement with or without leukaemia, very poor prognosis) and its molecular phenotype: CD4+, CD56+, CD123+ and ‘lineage negative’. In an editorial in the same issue, an important role of CD56 antigen expression was highlighted in making the diagnosis of cutaneous lymphomas. The need for clinical and histopathological vigilance to recognize and establish the correct diagnosis was also emphasized.3 We report the surprising case of a blastic NK cell‐lymphoma which does not express the CD56 antigen. An 87‐year‐old man presented with a 5‐cm slightly reddish cutaneous nodule on the forehead (Fig. 1). The staging was normal and local radiotherapy was performed. A complete remission of 1 years's duration was obtained. The patient then relapsed with skin, cervical lymph node and bone marrow infiltration, and a leukaemic phase. Treatment with oral etoposide (Vepesid®; Bristol‐Myers Squibb, Plainsboro, N.J., U.S.A.) induced a short stabilization. The patient died of his disease 2 years after the initial diagnosis.