Differentiated thyroid cancers were found in mother and son. The diagnosis was made first in the boy where papillary and follicular cancer with lymph node involvement and lung metastatic dissemination was diagnosed at the age of 9. Treatment by surgery, radioiodine and thyroid hormones was highly effective. 1 year later, thyroid surgery was performed on his mother but the diagnosis of poorly differentiated follicular thyroid cancer was made only 4 years later when the primary tumour was already unresectable and distant metastases present. In spite of treatment, the disease followed a lethal course in the mother. The familial occurrence of’differentiated thyroid cancer is extremely rare and this report is the first where neither previous radiation exposure nor familial colonic polyposis were detected.

Differentiated (papillary) thyroid cancer was detected 17 years following radioiodide ¹³¹I treatment for toxic multinodular goiter. 21 cases of thyroid cancers with previous ¹³¹I therapy for hyperthyroidism were summarised. This combination is rare compared to the incidence of thyroid cancers following external irradiation. This may be due to higher absorbed dose to thyroid in ¹³¹I treatment.

No abstract