Prognostic analysis demonstrated: (1) Significantly inferior survival in high-grade versus low-grade groups (P<0.05); (2) Lymph node metastasis, advanced stage, Ki-67>20%, and high-grade histology significantly correlated with reduced overall survival (P<0.05); (3) Lymph node metastasis constituted an independent poor prognostic factor (HR=12.73, 95%CI: 1.22-132.96).<h4>Conclusions</h4>PMEC exhibits distinct clinicopathological features, with MAML2 rearrangement present in approximately half of cases. The gene discussed is MAML2; the disease is metastatic malignant neoplasm in the lymph nodes.