Multiple Brain Metastases from a Diffuse Sclerosing Variant of Papillary Carcinoma of the Thyroid

We report a 53-yr-old man who presented with multiple brain metastases from a diffuse sclerosing papillary carcinoma of the thyroid. The presenting clinical features were those of an intracranial space-occupying lesion. Three brain tumors, confirmed pathologically to be metastatic thyroid papillary carcinomas, were removed. Two weeks after craniotomy, total thyroidectomy with cervical lymph node dissection was performed. Both lobes of the thyroid were diffusely enlarged and firm with a dominant mass. Histologically, the tumor was characterized by a combination of bilateral diffuse involvement of the gland, marked fibrosis, squamous metaplasia, abundant psammoma bodies, lymphocytic infiltration, frequent lymphatic and blood vessel permeation of the tumor, and typical elements of a conventional papillary carcinoma. In addition to these histologic findings, elements of other papillary carcinoma variants such as follicular and tall cell variants were also found focally. Twenty-three of twenty-four resected bilateral lymph nodes showed metastases of papillary carcinoma. Although the diffuse sclerosing variant of papillary carcinoma of the thyroid seems to be recognized as an aggressive variant of papillary carcinoma, there is no previous report of brain metastasis from this variant.