Diffuse sclerosing papillary carcinoma (DSPC) is a variant of papillary thyroid carcinoma (PTC), but it shows more aggressive clinical course and a poorer prognosis than the other types of PTC. Most PTCs show a focal nodular pattern in the thyroid on the imaging modalities, but DSPC reveals a diffuse infiltrating configuration in the thyroid without any focal nodular lesion. To our knowledge, there are scant radiological reports of diffuse sclerosing variant of papillary thyroid carcinoma. In this report, we present the case of a patient with DSPC who showed the characteristic findings on sonography and computed tomography.