Thyroid Research Thyroid Research Archive Thyroid Cancer

Hurthle-cell carcinomas of the thyroid may have features of either papillary carcinomas or follicular carcinomas

(March 2006)

The background of the study. Hurthle cells, also called oncocytic cells, are thyroid follicular cells that have a characteristic granular appearance. Some thyroid adenomas and carcinomas are composed largely of these cells, and they are also found in other thyroid disorders, for example, Hashimoto’s thyroiditis. Among Hurthle-cell carcinomas, some have the characteristics of follicular carcinomas, and others have the characteristics of papillary carcinomas, including the Ret/PTC gene rearrangements found in many papillary carcinomas. In this study, the course of patients with Hurthle-cell carcinoma was determined.

How the study was done. Forty-five patients with Hurthle-cell carcinoma were identified from a cohort of 661 patients with differentiated thyroid carcinoma (7 percent). The tumors ranged from 0.5 to 8.0 cm in size. They were multifocal in 15 patients (33 percent), and had spread to regional lymph nodes in 25 (56 percent); these are characteristics of papillary carcinoma. The tumor had invaded the capsule of the tumor in 9 patients (20 percent) and blood vessels in 7 (16 percent); these are characteristics of follicular carcinoma. Most patients were treated with total thyroidectomy and radioactive iodine.

The results of the study. At the time of the study, 40 patients (89 percent) were alive with no evidence of disease, 3 had recurrent carcinoma, and 2 had died of carcinoma; the median duration of follow-up was 94 months. The overall survival rate was 96 percent at five years.

In a separate study, 34 of 50 Hurthle-cell adenomas and carcinomas (68 percent), as defined by histology, expressed the Ret/PTC oncogene, indicative of papillary-carcinoma lineage.

The conclusions of the study. Some Hurthle-cell carcinomas of the thyroid have characteristics of papillary carcinomas, whereas others have the characteristics of follicular carcinomas.

The original article. Maxwell EL, Palme CE, Freeman J. Hurthle cell tumors: applying molecular markers to define a new management algorithm. Arch Otolaryngol Head Neck Surg 2006;132:54-8.