Thyroid Research Thyroid Research Archive Thyroid Cancer

The presence of atypical cells in aspirates of follicular tumors suggests the presence of cancer

(March 2007)

The background of the study. Thyroid nodules that are papillary cancers can be distinguished from those that are benign on the basis of the cytology of the cells obtained by biopsy of the nodules. However, it has proven difficult to distinguish between follicular cancers and benign follicular adenomas. This study was done to assess the value of cytologic details of the tumor cells and also clinical and ultrasound findings in distinguishing between these types of tumors.

How the study was done. The study group was 505 patients with thyroid nodules that had been aspirated and for which the cytologic diagnosis was follicular tumor. The ultrasound scans of the nodules were analyzed for echo appearance, microcalcifications, and blood vessels. The nodule aspirates were categorized as follicular tumor without atypical features (scant colloid, small follicles, and increased cells) and follicular tumor with atypical features (no colloid, many nests of cells, and isolated cells with large nuclei).

The results of the study. Among the follicular tumors, 27 percent proved to be cancers. Among the benign nodules, 76 percent were follicular adenomas, 14 percent were hyperplastic nodules, 9 percent were oxyphilic adenomas, and 1 percent were lymphocytic thyroiditis. Atypical cells were seen in the aspirates of 101 nodules. Forty-six percent were cancers, as compared with 20 percent of the nodules with no atypical cells.

There was no association between age, sex, number of nodules or nodule size, and cancer. Among the ultrasound findings, only the presence of microcalcifications was associated with cancer.

The conclusions of the study. Approximately 25 percent of thyroid nodules for which the cytologic diagnosis is follicular tumor prove to be cancers, and the likelihood of cancer is increased when atypical cells are seen in aspirates of the nodule.

The original article. Rago T, Di Coscio G, Basolo F, Scutari M, Elisei R, Berti P, Miccoli P, Romani R, Faviana P, Pinchera A, Vitti P. Combined clinical, thyroid ultrasound and cytological features help to predict thyroid malignancy in follicular and Hürthle cell thyroid lesions: results from a series of 505 consecutive patients. Clin Endocrinol (Oxf) 2007;66:13-20.