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Patients with multiple thyroid nodules are as likely to have a thyroid carcinoma as are patients with a solitary nodule

(November 2006)

The background of the study. Patients with either one or multiple thyroid nodules may have a thyroid carcinoma, but whether the frequency of carcinoma varies according to the number of nodules is not clear. The prevalence of carcinoma in patients with a solitary nodule and those with multiple nodules was determined in this study.

How the study was done. The study subjects were 1985 patients with one or more thyroid nodules >1 cm in longest dimension, as determined by ultrasonography, who underwent fine-needle aspiration biopsy. All patients in whom the biopsy was suspicious or positive for carcinoma underwent bilateral thyroidectomy; the final diagnosis in these patients was based on histopathologic study of the nodules.

The results of the study. The 1985 patients had 3483 nodules. The frequency of carcinoma was similar (15 percent) among the 1181 patients who had one nodule and the 804 patients who had multiple nodules (Table). The frequency of carcinoma per nodule was higher in the patients with a solitary nodule (15 percent) than in the patients with multiple nodules (8 percent). Among the patients with multiple nodules, the frequency of carcinoma decreased progressively as the number of nodules increased, from 13 percent in patients with 2 nodules to 4 percent in those with > or = to4 nodules.

Table. Frequency of Thyroid Carcinoma per Patient and per Nodule in 1985 Patients.
No. of Nodules	No. of Patients	No. of Patients with Carcinoma	No. of Nodules	No. of Carcinomas
Single	1181	175 (15%)	1181	175 (15%)
Multiple	804	120 (15%)	2302	187 (8%)
2	425	73 (17%)	848	107 (13%)
3	213	27 (13%)	639	47 (7%)
> or = to4	166	20 (12%)	815	33 (4%)

Among the 120 patients with multiple nodules who had a carcinoma, it was the largest nodule in 87 (72 percent). The carcinoma was the largest nodule in 86 percent of the patients who had 2 nodules, 59 percent of those who had 3 nodules, and 40 percent of those who had > or = to4 nodules.

The conclusions of the study. Among patients with thyroid nodules, the frequency of carcinoma per patient is similar in those with one nodule and those with multiple nodules, although the frequency of carcinoma per nodule decreases as the number of nodules increases.

The original article. Frates MC, Benson CB, Doubilet PM, Kunreuther E, Contreras M, Cibas ES, Orcutt J, Moore FD Jr, Larsen PR, Marqusee E, Alexander EK. Prevalence and distribution of carcinoma in patients with solitary and multiple thyroid nodules on sonography. J Clin Endocrinol Metab 2006;91:3411-7.