Lymphoblastic lymphoma of natural killer cell origin, presenting as pancreatic tumour

Aims We describe the first case of lymphoblastic lymphoma (LBL) of natural killer (NK) cell origin initially presenting as a pancreatic tumour, and review this type of lymphoma. Methods and results A 38‐year‐old woman with abdominal pain was found to have a pancreatic mass. Twenty days later, she developed diffuse lung infiltrates and leucoerythroblastosis of the peripheral blood, and her bone marrow was diffusely infiltrated with blasts. The blasts were positive for CD56, CD16 and P‐glycoprotein, but lacked cytoplasmic azurophilic granules, T, B and myeloid cell markers on the cell surface, rearrangement of the genes for T‐cell receptor and immunoglobulin, and the Epstein–Barr virus (EBV) genome. The diagnosis was LBL of NK cell origin. She received aggressive therapy, but died of the lymphoma. In contrast to ordinary NK‐cell lymphoma, this case and reported cases of LBL of NK‐cell origin showed the following common characteristics. The tumour cells often lack cell surface CD2, cytoplasmic CD3, cytoplasmic azurophilic granules, and EBV genome. The prognosis was extremely poor. Conclusions LBL of NK‐cell origin should be included in the differential diagnosis of pancreatic tumours. To fully characterize this type of lymphoma, further cases must be evaluated.