Primary cutaneous NK/T-cell lymphoma of nasal type: an age-related lymphoproliferative disease?

Among extranodal NK/T-cell lymphoma of nasal type (NKTL), the extranasal variant (ENKTL) is known to have a worse prognosis with advanced clinical stage than the nasal variant of NKTL. However, detailed clinicopathological features of the localized extranasal disease have not been well documented in English literature. Here, we described the clinicopathological profiles of 14 patients with stage I ENKTL, including 7 in the skin, 5 in the gastrointestinal tract, and 2 in the central nervous system, highlighting the distinctiveness of the first. The 7 primary cutaneous (PCNKTL) cases were characterized by an older onset age (median, 76 versus 53 years, P = .012) and a more favorable clinical course (P = .041) compared with 17 patients with stages II-IV ENKTL that showed cutaneous involvement. The skin lesions in the PCNKTL group were distributed in the face or neck (n = 4) and limbs (n = 3) but not the trunk, which was most frequently affected (60%, P = .017) in the latter group. Furthermore, the stage I cutaneous disease showed a female predominance (male-female, 2:5 versus 7:0; P = .021) and a significantly more favorable survival compared with the noncutaneous stage I ENKTL (P = .037). These results suggest that PCNKTL constitute a distinct subgroup in the nasal-type lymphoma spectrum.