Pure clear cell papillary thyroid carcinoma with chronic thyroiditis: report of a case.

We herein report a case of pure clear cell papillary thyroid carcinoma, which is the first reported case in Japan. The tumors measured 1.0 x 0.9 and 0.7 x 0.4 cm in size. An ultrasonographical examination revealed hypoechoic irregular-shaped lesions with fine internal calcifications. No lymph node metastasis was observed in any of the surgical specimens. Distant metastasis had not been observed as of 6 years after surgical treatment. The number of cases of pure clear cell papillary carcinoma reported so far are too few to clearly elucidate its characteristics; however, the ultrasonographical findings and biological behavior of this case were compatible with those of non-clear cell papillary thyroid carcinoma.