Last update:
15-Jul-2013

OBJECTIVE Investigation of the clinical findings in 661 Japanese patients with thyroid nodules, of which 288 (44%) were malignant.

METHOD AND RESULTS Of the 288 malignant thyroid nodules, histological examination showed papillary carcinoma (Ca) in 249 (86.5%), follicular Ca in 28 (9.7%), undifferentiated Ca in 4 (1.4%), and medullary Ca in 7 (2.4%). Even among the 104 cases of papillary Ca with normal serum levels of thyroglobulin (Tg) (4−78 ng/mL), microscopic cervical lymph node (CLN) metastases were identified in 84% at thyroidectomy. All 28 cases of papillary Ca with Tg >500 ng/mL showed extra-thyroid metastases, and an anti-Tg antibody level of >=100 U/ mL was detected in 10. High Tg secretion (>10,000 ng/mL) from soft tissue, bone or lung metastases was detected in 9 (32%) cases of follicular Ca and in 2 (50%) of undifferentiated Ca, in which metastatic curettage improved the clinical findings. Tg levels of 4,000−10,000 ng/mL were observed in 7 (25%) cases of follicular Ca and 1 (25%) of undifferentiated Ca. One elderly female with follicular Ca and Tg >10,000 ng/mL developed bone marrow dysplasia with proliferation of p53- and CD163-positive macrophages and peripheral pancytopenia 28.5 years after the diagnosis of thyroid Ca. Patients with follicular Ca with relatively low Tg of <2,000 ng/mL more commonly exhibited early lung metastases. The thyroid Ca, in 12 (4.8%) patients with papillary Ca and 1 (3.6%) with follicular Ca suspected of Cowden syndrome (CS), was associated with bilateral breast Ca, with a good prognosis, apart from 2 cases with high Tg levels (673 and 704 ng/mL).

CONCLUSIONS Thyroid Ca had very early extra-thyroid metastases but a long survival rate.

Key words: Bone, soft tissue metastasis, Breast cancer, Cervical lymph node metastasis, Metastatic cancer activation, Serum thyroglobulin, Thyroid cancer.