Coexistence of Histologically Proven Chronic Lymphocytic Thyroiditis with Other Thyroid Disorders: A Retrospective Study.

Hashimoto's thyroiditis (HT) is the commonest autoimmune thyroid pathology. It has been reported in increased numbers recently, probably due to the increase in autoimmune diseases across many parts of the world. It is sometimes found associated with other diseases as well as other diseases of the thyroid. There is an unproven association of this condition with thyroid cancer, particularly papillary thyroid carcinoma (PTC).  This was a retrospective study performed over a period of 5 years. The objectives of this study were to find out the prevalence of histopathologically proven HT in surgically resected thyroid glands for various indications and its association with other thyroid disorders, especially thyroid malignancies. Total 4,630 patients who underwent thyroidectomy during the study period and met the criteria for inclusion were considered for analysis.  Histopathologically proven features of HT were present in 1,295 (28%) of the cases. Among these, 445 (34.36%) had only HT while 850 (65.66%) had HT along with other thyroid diseases. The most common disease associated with HT was multinodular goiter (44.2%), followed by PTC (15.2%). Patients with HT exhibited a higher rate of papillary cancer (16.7%) compared with patients without this pathology (13.8%). Statistically significant association between papillary cancer and HT was found among the female patients.  The prevalence of HT in patients undergoing thyroidectomy is high in the studied population. A statistically significant association exists between papillary thyroid cancer and thyroiditis among female patients. This could form the basis for further research along these lines.