Sclerosing papillary carcinoma of the thyroid with tubular features

A case of papillary thyroid carcinoma (PTC) in a twenty-seven year old female is reported. The patient presented with complaints of a goiter and associated dysphagia. Histologically, the tumor was characterized by diffuse growth of branching tubules lined by a single layer of the tumor cells and surrounded by circularly arranged fibrous tissue of variable thickness. Focally, micropapillary projections of the epithelium budding into the lumen of tubules were visible. The cells showed features of PTC (overlapping ground glass nuclei, multiple grooves and pseudoinclusions). Nevertheless, no areas of "classical" PTC were identified. A striking feature was the presence of a severe lymphoplasmocytic infiltrate and the presence of plentiful S-100 protein positive dendritic/Langerhans cells. The tumor shares several features with diffuse sclerosing PTC, namely the age and sex of the patient, the infiltrative growth pattern and the presence of severe chronic thyroiditis that is associated with a large number of dendritic/Langerhans cells in the background. There are, however, several distinct differences - particularly the absence of massive squamous metaplasia, psammoma bodies, areas of classical PTC, and also lack of invasion of lymphatic vessels. We believe that this tumor represents an unusual example of diffuse sclerosing PTC with special tubular features.