Association of different pathologic processes of the thyroid gland in fine needle aspiration samples

OBJECTIVE: To evaluate the possible significant association between different pathologic processes of the thyroid gland. STUDY DESIGN: From a series of 10,039 fine needle aspiration biopsies of the thyroid gland, a total of 1,330 cases were aspirated involving two or more palpable nodules. In 103 (1%) cases, two different pathologic processes were cytologically diagnosed. Statistical analysis was performed through four two-tailed chi 2 tests to evaluate the following events: (1) mononodularity and multinodularity vs. neoplasms, (2) colloid goiter and neoplasms, and (3) all neoplasms vs. colloid goiter and lymphocytic thyroiditis. All tests were performed using < .05 as the probability level. RESULTS: Simultaneous pathologic processes observed were: goiter and chronic lymphocytic thyroiditis (32), goiter and Hashimoto's thyroiditis (21), goiter and subacute granulomatous thyroiditis (8), goiter and follicular neoplasm (9), and goiter and papillary carcinoma (14). In 12 cases we found goiter and Hürthle cell tumor, goiter and medullary thyroid carcinoma (2), papillary thyroid carcinoma and Hashimoto's thyroiditis (2), Graves' disease and lymphocytic thyroiditis (2), and follicular neoplasm and lymphocytic thyroiditis (1). Statistical analysis showed significant association between multinodularity and neoplasms (P < .001), while the association between goiter and any type of neoplasia was not statistically significant. All the neoplasms taken together were associated with lymphocytic thyroiditis and goiter (P < .005). CONCLUSION: While there may be no statistically significant associations between the individual pathologies, it seems that having one pathology increases the risk of developing another. All the palpable nodules in the same gland should be investigated by fine needle aspiration in order to improve diagnostic sensitivity and to identify occult neoplasms.