The histological rarity of thyroid cancer

Thyroid cancer is the most common endocrine cancer, accounting for about 1% of all cancers. Sarcomas, lymphomas and metastases to the thyroid gland are rare and only with a handful of descriptions in the literature. Objective: To describe rare histological types of thyroid cancer found in a reference center. Methods: Medical chart review from admitted patients diagnosed with thyroid cancer in the period from 1977 to 2010. Demographic, diagnostic, therapeutic and histopathological information were collected. Results: 3,018 records of patients admitted with thyroid disease were reviewed. Among the cases diagnosed with rare tumors there was a predominance of: anaplastic carcinoma: 22 cases (0.7%), followed by 11 cases of medullary carcinoma (0.36%); 2 cases of sarcoma (0.07%), 2 cases of lymphoma (0.07%) and one case of metastatic carcinoid tumor (0.03%). There were more females diagnosed (57%) as well as Caucasians (84%). The most frequent clinical presentation was a palpable thyroid nodule. All patients with lymphoma, sarcoma and anaplastic carcinoma died. Conclusion: Sarcomas, lymphomas and thyroid metastases are uncommon and tend to worse outcomes.