Non-solid type thyroid carcinoma: a case report of moderately differentiated adenocarcinoma of the thyroid

We report the case of a common type papillary thyroid carcinoma (PTC) patient who developed early recurrence and persistent disease even after ablation therapy. The patient was an 80-year-old man that was incidentally found to have a mass lesion in the left lower lobe of his thyroid. A total thyroidectomy and a left side modified radical neck dissection were performed; histological examination revealed a common type PTC. The patient underwent lymph node dissection twice for recurrence and (131)I-Na ablations for fluctuated elevation of serum thyroglobulin. The resected tumor and recurrence in lymph nodes revealed non-solid type papillary carcinoma with mixed features of less well-differentiated morphology, which we suggest included loss of cellular polarity/cohesiveness, tall cells and columnar cells. Immunohistochemistry revealed high a MIB-1 labeling index (15-20%) in both the primary tumor and the metastatic tumor in the lymph nodes. p53 immunoreaction was found positive at very low level (<5%). E-cadherin was faintly positive in a few cells of the primary tumor and negative in the metastatic site. We recently proposed a new classification for follicular cell tumors of the thyroid gland, and this case is an example of moderately-differentiated adenocarcinoma according to our classification.