Histological appearance of small thyroid carcinoma.

Histopathological characteristics of the tumor growth were studied in 59 small carcinomas detected in thyroids at autopsy and in 33 from surgically removed thyroids. Tumor size was less than 5 mm in 56 of the 59 carcinomas (95 per cent) detected in autopsy materials. Histological findings of the small carcinomas were papillary adenocarcinoma in 45 of 59 (76 per cent), and sclerosing carcinoma in 32 (54 per cent). Among these 59 small carcinomas, intrathyroid metastases were found in six (10.2 per cent). In small carcinomas measuring less than 5 mm, carcinomas in females had an average diameter of 2.19 mm and were significantly larger than those found in male, having an average diameter of 1.14 mm (p less than 0.05). In small carcinomas from the surgical specimen, incidence lymph node metastasis was high when associated with numerous intrathyroid metastases and when the distance was great between the edge of the primary tumor and the farthest satellite metastatic focus.