Clinicopathological factors associated with the prognosis and relapse of primary cutaneous marginal zone lymphoma: a retrospective cohort study.

Primary cutaneous marginal zone lymphoma (PCMZL) is a rare extranodal B-cell lymphoma with limited data available in Asian populations. We reviewed 56 primary and 10 secondary CMZL cases (1995-2024) diagnosed at Asan Medical Center (Seoul, Korea). The PCMZL cohort showed an equal sex distribution, and lesions most frequently involved the head and neck (53.6%). Autoimmune diseases were present in 10.7% of PCMZL patients. Five-year overall survival for PCMZL was 96.4%, although only 39.3% maintained complete remission. Single lesions were significantly associated with initial clinical remission (p = 0.032). Widespread disease (other than T1a or T2a), older age (≥ 65 years), and underlying autoimmune disease were significantly associated with shorter relapse-free survival (RFS). Multivariate analysis identified autoimmune disease as an independent predictor of shorter RFS (p = 0.018). These findings suggest distinct clinical features of PCMZL in Korean patients, including sex ratio and lesion distribution, that differ from Western studies.