Clinical features associated with high pathological grade in primary thyroid lymphoma

This study aimed to identify clinical features associated with high pathological grade (HG) in primary thyroid lymphoma (PTL), through a systematic review and meta-analysis. Electronic databases were searched for studies assessing PTL. Extracted data were age, sex, lymph node involvement, symptoms, lymphocytic thyroiditis, serum tumor markers; the association with HG was assessed by using odds ratio (OR), with a significant p-value<0.05. Twenty-four studies with 1916 PTLs were included. HG was significantly associated with age≤55 (OR = 0.54; p < 0.0001); female sex (OR = 1.31; p = 0.02), lymph node involvement (OR = 2.23; p < 0.00001), compressive symptoms (OR = 2.61; p < 0.0001), absence of lymphocytic thyroiditis (OR = 0.45; p = 0.0002), and increased LDH levels (OR = 4.90; p < 0.00001), but not with age>60 (OR = 0.74; p = 0.24), age>70 (OR = 1.16; p = 0.66), and B symptoms (OR = 1.30; p = 0.54). In conclusion, Age≤55, female sex, lymph node involvement, compressive symptoms and absence of lymphocytic thyroiditis may be predictive factors for HG in PTL. On the other hand, B symptoms does not seem to be associated with pathological grade.