[Extranodal NK/T cell lymphoma, nasal type with local recurrence in the contralateral nasal cavity 15 years after initial sequential chemoradiotherapy].

A 72-year-old woman was diagnosed with extranodal NK/T cell lymphoma of the right nasal cavity and received sequential radiochemotherapy comprising focal radiotherapy and THP-COP chemotherapy. Showed a complete tumor response to the treatment; however, the tumor recurred in the contralateral right nasal cavity 15 years after the initial treatment. This was judged to be a marginal recurrence in the radiation field. After four cycles of dexamethasone, methotrexate, ifosfamide, L-asparaginase, and etoposide (SMILE) chemotherapy, a second complete response was achieved. It is possible that another recurrence occurs in the future, and if the lesion is localized at the time of recurrence, it may be possible to control the disease again. Careful follow-up is considered necessary.