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.
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