Hürthle cell follicular carcinoma (HCFC) of the thyroid gland is a malignant tumour composed predominantly or entirely of oncocytes (also called “Hürthle” or “Askenazy” cells),¹ arranged in a follicular/trabecular pattern without the cytological changes found in papillary carcinoma.^1,2 Although most studies have demonstrated that HCFC and follicular thyroid carcinoma share similar clinical behaviour and prognosis,³ recently the World Health Organization (WHO) has classified HCFC as a separate and distinct entity.⁴ Anaplastic thyroid carcinoma accounts for 5–10% of all thyroid cancers and represents the most aggressive thyroid tumour almost invariably associated with a fatal outcome.⁵ Most anaplastic thyroid carcinoma cases show evidence of a pre-existing differentiated, or poorly differentiated, thyroid carcinoma.^2,5 At present, to our knowledge, the secondary leptomeningeal localisation of thyroid HCFC has not yet been reported in the literature.

CASE REPORT

We describe the case of a 56-year-old woman who was admitted to the hospital due to a 3-day history of partial seizures, unsteady walk with frequent falls and dysarthria. She had no history of either neck irradiation or thyroid diseases in her family. Fifteen years before, laboratory and imaging investigations disclosed a euthyroid goitre with a 15 mm hypoechoic, scintigrafically “cold”, nodule in the left thyroid lobe. She was not submitted to fine-needle aspiration biopsy, …