Features of papillary thyroid microcarcinoma in the presence and absence of lymphocytic thyroiditis

It is known that the prevalence of lymphocytic thyroiditis (LT) is higher in patients with papillary thyroid carcinoma (PTC), that gender influences this association, and that certain features of PTC occur more frequently in patients who also have LT. These relationships have not been studied in patients with papillary thyroid microcarcinomas (PTMC), however. Therefore, we performed a study to compare the clinical and pathological features of patients with PTMC who did and did not have LT. We collected the 323 consecutive patients following excision of PTMC diagnosed as papillary carcinoma on preoperative needle aspiration cytology. We analyzed the demographic, serologic, and pathologic data of those cases with categorization into four groups based on presence of LT and neck lymph node metastasis. In all PTMC, the presence of LT did not influence the frequency of lymph node metastasis (27 of 105 [25.7%] vs. 48 of 218 [22.0%]). Among the patients with metastatic PTMC, LT was noted significantly more often in female than male patients (95.2% vs. 79.8%). In metastatic PTMC, multifocality and bilaterality was more frequent in with LT than without LT (44.4% vs. 29.2%; 29.6% vs. 14.6%). Both the presence of serum thyroglobulin antibody (TgAb; p = 0.016) and serum microsomal antibody (p = 0.013) were highly correlated with the presence of LT. Twenty-seven of 105 patients (25.7%) with PTMC with LT had nodal metastasis. Co-existing LT was noted predominantly in women, influenced more often multifocality and bilaterality of tumors, and higher frequency of metastasis to lateral compartment lymph nodes.