Cutaneous extranodal natural killer/T-cell lymphoma: A comparative clinicohistopathologic and survival outcome analysis of 45 cases according to the primary tumor site

Background: Differences in survival outcomes and prognostic factors of cutaneous extranodal natural killer/T-cell lymphoma (ENKTL) depending on primary tumor site are currently unknown. Objective: We sought to analyze the clinicopathological features and survival outcomes of cutaneous ENKTL according to primary tumor site. Methods: In all, 45 patients with cutaneous ENKTL were classified with: (1) primary cutaneous ENKTL, or (2) nasal ENKTL with cutaneous involvement. Clinicopathologic features, survival outcomes, and prognostic factors were analyzed using patient's medical records. Survival outcomes were analyzed using the Kaplan-Meier method and compared using the log rank test. The Student t test, Fisher exact test, and linear by linear association test were used to analyze clinicopathologic differences between groups. Results: Clinical manifestations of cutaneous ENKTL included solitary or multiple subcutaneous nodules and cellulitis or abscess-like lesions. Primary cutaneous ENKTL demonstrated a less aggressive clinical course and better survival outcomes. The extent of cutaneous lesions demonstrated a significant effect on the prognosis of primary cutaneous ENKTL, but not on nasal ENKTL with cutaneous involvement. The presence of nasal lesions in primary cutaneous ENKTL was associated with poor prognosis. Limitations: This study used a retrospective design and included a small sample size. Conclusion: Although the clinicopathological features were similar regardless of subgroup, survival outcomes and prognostic factors differed depending on the primary tumor site of cutaneous ENKTL.