Thyroid Research Thyroid Research Archive Thyroid Cancer

Patients with poorly differentiated thyroid carcinoma have a poorer prognosis than those with well-differentiated carcinomas

(July 2004)

The background of the study. Insular carcinomas, trabecular carcinomas, and solid carcinomas are known as poorly differentiated carcinomas. This retrospective study was done to assess the pathologic features and outcome in patients with these tumors.

How the study was done. Among 2900 patients with thyroid carcinoma, 183 (6 percent) had insular, trabecular, or solid carcinomas, as defined by the presence of masses of thyroid cells arranged in nests or islands (insular pattern) or networks or solid masses (trabecular-solid pattern). The patients’ records were reviewed, and their outcome was compared with that of patients with papillary carcinoma, follicular carcinoma, and anaplastic carcinoma.

The results of the study. There were 127 women and 56 men. The mean tumor size was 5 cm. The predominant growth pattern was insular in 50 percent and trabecular-solid in 50 percent. The mean number of dividing cells per 10 high-power fields was 2.2; areas of cell destruction were seen in 47 percent of the tumors; and invasion of blood vessels by tumor was seen in 54 percent (these findings are rare in papillary or follicular carcinomas).

Most patients were treated by surgery and radioiodine. At last follow-up, 91 patients (50 percent) had no evidence of cancer, 37 (20 percent) were alive with cancer, 42 (23 percent) had died of thyroid cancer, and 13 (7 percent) had died of other causes. The 5- and 10-year survival rates were, respectively, 85 and 67 percent. These rates were intermediate between the rates in patients with papillary or follicular carcinoma and those in patients with anaplastic carcinoma.

The conclusions of the study. Insular, trabecular, or solid thyroid carcinomas are more aggressive than papillary or follicular thyroid carcinomas.

The original article. Volante M, Landolfi S, Chiusa L, Palestini N, Motta M, Codegone A, Torchio B, Papotti MG. Poorly differentiated carcinomas of the thyroid with trabecular, insular, and solid patterns: a clinicopathologic study of 183 patients. Cancer 2004;100:950-7.