Prognosis of minute carcinoma of thyroid. Follow-up study of 49 patients.

Forty-nine patients with minute carcinoma of thyroid gland (clinically silent carcinoma less than 10 mm in diameter) underwent partial thyroidectomy and regional lymph node dissection. Nodal metastasis was found in 33 patients (67%). Histologically, no difference in the incidence of nodal metastasis was found between sclerosing carcinoma and nonsclerosing carcinoma. During the period of follow-up (from 3 to 18 years), neither recurrence of the carcinoma nor death was observed in 16 patients without nodal metastasis and 24 patients who had less than 4 metastatically involved nodes. In these 24 patients, most of the metastatic deposits were less than 5 mm in diameter and even the largest one did not exceed 16 mm. Recurrence without death was found in 2 of 4 patients who had many metastatically involved nodes, more than 8, or at least one large metastatic deposit measuring larger than 16 mm in diameter (moderately involved group), whereas recurrence followed by death occurred in 3 of 5 who had many involved nodes and at least one large deposit (extensively involved group). In both moderately and extensively involved groups, recurrence and death occurred in elder patients. The present study suggested that the prognosis of minute carcinoma depends on the degree of nodal involvement and age of the patient.