Adult aggressive natural killer cell leukemia.

INTRODUCTION

Aggressive natural killer cell leukemia (ANKL) is a rare malignancy with a poor prognosis.

METHODS

Clinical and laboratory data of 20 patients with ANKL were collected retrospectively from a single medical center.

RESULTS

The prominent clinical complications included unexplained fever, interstitial pneumonia, hepatosplenomegaly, high level of lactate dehydrogenase and liver dysfunction. Both bone marrow (BM) biopsies and aspiration of 20 patients were morphologically and immunophenotypically evaluated. Only 2 patients with marked elevation of peripheral large granular lymphocytes had sufficient BM aspiration for flow cytometric immunophenotyping. However, 20 BM biopsies showed marked neoplastic cell infiltration, and immunohistochemistry highlighted patterns of neoplastic involvement. The neoplastic cells were mainly positive for CD2, CD56, (Equation is included in full-text article.)and Epstein-Barr virus (EBV)-encoded RNA. The plasma EBV-DNA test was positive in all cases, and complex cytogenetic abnormalities were identified in 8 cases. The median survival of the patients was 8 weeks, and the presence of liver dysfunction-induced jaundice (serum total bilirubin level > 34.2 μmol/L) was identified as a risk factor for early death. Patients were generally resistant to chemotherapy, but notably, 3 patients demonstrated a marked response to gemcitabine with tolerable toxicities.

CONCLUSIONS

These findings indicate that ANKL is a highly aggressive leukemia with a fulminating clinical course. A BM biopsy with immunohistochemistry and EBV-encoded RNA detection is mandatory for a rapid diagnosis of ANKL. Therefore, a careful evaluation and fully supported treatment plan should be conducted before chemotherapy is administered to patients with severe complications to improve the overall survival.