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.

To describe rare histological types of thyroid cancer found in a reference center.

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.

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.

Sarcomas, lymphomas and thyroid metastases are uncommon and tend to worse outcomes.