[Diffuse sclerosing papillary carcinoma of the thyroid. Report of a case].

The authors report the case of a 12-year-old girl presenting with a diffuse sclerosing papillary carcinoma of the thyroid. The diagnosis was made on a total thyroidectomy specimen three months after thyroid enlargement was detected. This child had previously been treated medically for thyroiditis because of an enlarged thyroid gland with serum antithyroid autoantibodies. A few cases have been described in the literature. Six morphologic findings define this variant of papillary carcinoma: a diffuse growth pattern involving one or both lobes of the thyroid, prominent fibrosis, heavy lymphocytic infiltration with germinal centers, large numbers of psammoma bodies, squamous metaplasia and papillae within cleft-like tissue spaces. Some authors stated that this variant has a poorer prognosis than the usual papillary carcinoma of the thyroid. However, in some series a few patients survive without local recurrence or distant metastasis at a mean follow-up period of more than 10 years. Immunohistochemical studies have shown high accumulation of S-100 protein positive dendritic cells. Such an infiltration has been correlated with a better prognosis.