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The ectopic thyroid gland is a rare condition. In most cases, ectopic thyroid tissue is the only functioning thyroid tissue, but it may rarely be associated with a normal thyroid gland. Ectopic thyroid carcinoma within a thyroglossal duct cyst is a very rare entity, with controversial individual approaches. This encouraged us to present the case of a 31-year- old woman, with papillary thyroid carcinoma in the thyroid gland and in the thyroid ectopic tissue within the thyroglossal duct. After suspicion of thyroid malignancy in the ultrasonography of the neck, FNA-biopsy was performed on the thyroid nodule and the thyroglossal duct cyst. Since the pathological exam revealed a papillary carcinoma in the eutopic and ectopic thyroid tissues, the Sistrunk procedure and total thyroidectomy were done, followed by radioiodine ablation.

We have measured the linear rheology of critically purified ring polyisoprenes, polystyrenes, and polyethyleneoxides of different molar masses. The ratio of the zero-shear viscosities of linear polymer melts η0,linear to their ring counterparts η0,ring at isofrictional conditions is discussed as a function of the number of entanglements Z. In the unentangled regime η0,linear/η0,ring is virtually constant, consistent with the earlier data, atomistic simulations, and the theoretical expectation η0,linear/η0,ring = 2. In the entanglement regime, the Z-dependence of ring viscosity is much weaker than that of linear polymers, in qualitative agreement with predictions from scaling theory and simulations. The power-law extracted from the available experimental data in the rather limited range 1 < Z < 20, η0,linear/η0,ring Z1.2±0.3, is weaker than the scaling prediction (η0,linear/η0,ring Z1.6±0.3) and the simulations (η0,linear/η0,ring Z2.0±0.3). Nevertheless, the present collection of state-of-the-art experimental data unambiguously demonstrates that rings exhibit a universal trend clearly departing from that of their linear counterparts, and hence it represents a major step toward resolving a 30-year-old problem.