Differences between nasal and extranasal NK/T-cell lymphoma.

摘要

We thank Suzuki et al for comparing the clinical outcome of their 10 patients with localized (stage I/II) nonnasal, extranodal NK/T cell lymphoma (ENKL) from a Japanese multicenter collection (3-year overall survival; 41%), to the 18 cases with similar disease from our international study (3-year overall survival; 12%). They suggest that low-stage extranasal ENKL may carry a more favorable prognosis.Due to differences in case selection criteria, it is difficult to resolve this discrepancy in a retrospective fashion. The small number of cases of low-stage extranasal ENKL in both studies means that this is a rare clinical presentation. From our understanding, most of the Japanese cases were dermatologic referrals. This category of cases was not submitted to our retrospective study. Indeed; none of our 18 stage I/II extranasal cases come from the 4 Japanese centers that participated in pur study.1 In contrast, only 2 of the 18 stage I/II cases from our study were cutaneous ENKL. The majority affected the alimentary tract (n = 7) and muscles (n = 5). Such bias may have led to the omission of a Japanese subcategory of limited stage cutaneous ENKL with a good prognosis, that is either not seen or missed in other parts of the world.