Pathologic study and clinical significance of hurthle cell papillary thyroid carcinoma.

摘要

Hurthle cell papillary thyroid carcinoma is a variant of papillary thyroid carcinoma (PTC). Its pathologic and clinical significance has not been well documented. The authors studied the relative incidence of Hurthle cell PTC and the relationship of Hurthle cell PTC to other variants of thyroid carcinoma. Three hundred eighty consecutive cases of thyroid carcinoma were reviewed to identify cases with focal or extensive areas of Hurthle cell PTC, classic PTC, Hurthle cell carcinoma (ie, non-Hurthle cell PTC), and follicular carcinoma. In addition, the status of lymphoid infiltrate in the tumor, stromal invasion with desmoplastic reaction, vascular invasion, and distant and lymph node metastasis were noted by microscopic examination, review of clinical charts, or both. A total of 24 (HCs) and 42 PTCs with Hurthle cells were identified. The latter category was divided into pure Hurthle cell PTC or extensive Hurthle cell (HPTC) (28 cases) and PTC or Hurthle cell carcinoma with focal areas of Hurthle cell PTC (14 cases). The Hurthle cell PTC/Hurthle cell carcinoma ratio was lower than that of PTC/follicular carcinoma (39:289) (P = 0.001). Follicular or solid structures were present in all HPTCs. HPTCs were associated with frequent stromal intrathyroid and extrathyroid invasion, but they tended to have a lower rate of lymph node metastasis (8/28) compared with classic PTC with stromal invasion (108:200) (P = 0.12) and a lower rate of distant metastasis (2:28) compared with Hurthle cell carcinoma (15:24) (P = 0.02) or follicular carcinoma (13:39) (P = 0.04). Warthin-like Hurthle cell PTC (10 cases) was associated with extrathyroid invasion in five cases. In Hurthle cell PTC associated with tall cell variant (10 cases), areas of gradual transition between Hurthle cell PTC and tall cell variant were identified. The latter variant showed the highest rate of extrathyroid stromal and vascular invasion with distant metastasis and patient death compared with all Hurthle cell PTCs and classic PTCs. In conclusion, Hurthle cell PTC is frequently associated with tall cell variant. It has a higher potential for extrathyroid invasion than classic PTC and has vascular invasion and distant metastasis characteristics intermediate between those of classic PTC and Hurthle cell carcinoma with or follicular carcinoma. Hurthle cell PTC tends to show a greater likelihood of extrathyroid invasion when associated with Warthin-like features and tall cell variant PTC, and higher vascular invasion and distant metastasis when associated with tall cell variant.