Prediction of malignancy in the solitary thyroid nodule by physical examination, thyroid scan, fine-needle biopsy and serum thyroglobulin. A prospective study of 100 surgically treated patients.

A prospective study was made of 100 consecutive patients selected for surgical treatment of a clinically solitary thyroid nodule. Anamnestic data and findings at physical examination, thyroid scan, fine-needle aspiration biopsy and measurement of serum thyroglobulin were correlated with the postoperative histologic diagnoses. The histologic findings were malignant in 18 cases and benign in 82. Familial occurrence of benign goiter was reported more frequently by patients with benign than by those with malignant histology (46 and 11%). Of the 11 nodules that were hard at palpation, 7 were malignant. All 12 scintigraphically "hot" nodules were benign, but 13 of 59 "solitary, cold" nodules were malignant. The cytologic specimens were reviewed and reclassified. The needle aspirate was insufficient for cytologic diagnosis in 11 cases. Papillary carcinoma was cytologically recognized in four cases. Of 36 lesions cytologically reported to be neoplasm of unspecified type, 12 were histologically shown to be malignant, 20 were follicular adenomas and 4 were colloid goiter. Benign lesion was the cytologic diagnosis in 47 cases. One diagnosis was false negative, but the cancer lay beneath the index nodule. The thyroglobulin level was significantly higher in patients with thyroid cancer than in those with benign disorders, but the test's predictive value was low. Thyroglobulin levels more than tenfold the upper limit of normal were found only in three patients with thyroid cancer and two with thyrotoxicosis. Although all of the mentioned investigative data were helpful in the management of solitary thyroid nodule, fine-needle biopsy was the best single method. When cytologic examination shows malignancy or unspecified neoplasm, surgery is indicated. For most patients with cytologically benign lesions, careful follow-up will suffice.