We describe a patient with natural killer (NK)/
T cell lymphoma who relapsed after autologous
peripheral blood stem cell transplantation (auto-PBSCT) and was successfully treated with Escherichia coli (E. coli) and Erwinia L-
asparaginase. A 38-year-old male patient with ulcerated
tumor at the left thigh was diagnosed as having nasal type NK/
T cell lymphoma on the basis of histopathological and flowcytometric findings of
tumor, revealing diffuse infiltration of atypical lymphoid cells into blood vessels and expression of CD7 and
CD56 antigens, but not CD3. He had
tumor infiltration in the bone marrow and at the right lower lung field. After five cycles of CHOP (
cyclophosphamide,
doxorubicin,
vincristine and
prednisolone)
therapy, the patient achieved complete remission and received high-dose
chemotherapy with auto-PBSCT, although the
tumor recurred in the right leg 10 months later. Despite salvage
chemotherapy, followed by local irradiation and
surgical amputation, a
tumor recurred at the left upper gingiva 10 days after. Using E. coli L-
asparaginase (6000 U/m2/day), the
tumor regressed,
fever was alleviated and the serum
lactate dehydrogenase decreased to normal range after several days. The
asparagine synthetase expression in
tumor cells was immunohistochemically negative on
paraffin-embedded tissues. Because of the
anaphylactoid reaction developing after E. coli L-
asparaginase, alternative Erwinia L-
asparaginase (6000 U/m2/day) was administered, resulting in regression of
tumor and
fever lysis. L-
asparaginase is a promising agent for the treatment of NK/
T cell lymphoma.