Diffuse sclerosing variant of papillary carcinoma of the thyroid: imaging and cytologic findings.

Diffuse sclerosing variant of papillary thyroid carcinoma (DSPC) is a rare variant of papillary thyroid carcinoma, for which the imaging and cytologic features have not been reported. The aim of this study is to gain better insight into the characteristic imaging and cytologic features of DSPC and to suggest treatment guidelines. We retrospectively analyzed the ultrasonographic and computed tomographic (CT) features in eight patients diagnosed with pathologically proven DSPC between 1996 and 2006. Of these eight patients, five patients underwent preoperative ultrasonography (US)-guided fine-needle aspiration (FNA). All the patients were women, who presented at a relatively young age (mean age: 31.9 years) with large tumors (mean diameter: 5.9 cm) and cervical lymph node metastases. The US features (7/8) of DSPC were heterogeneous echotexture (7/7), solid composition (7/7), ill-defined margins (4/7), scattered microcalcifications having snowstorm appearance (7/7), and various echogenicities. CT findings (6/8) revealed numerous microcalcifications and multiple enlarged nodes in all the patients. Cytological examination showed lymphocytes intermingled with nests of tumor cells, psammoma bodies, and squamous differentiation with typical nuclear features of papillary carcinoma in all. Through the combination of typical imaging findings and careful cytological examination, DSPC can be diagnosed preoperatively, allowing for the aggressive surgical treatment required in treating this disease.