Three years ago we reviewed our experience with nodular thyroid glands.1 We concluded, then, that the usefulness of any histologic classification of cancer of the thyroid is inversely proportional to its complexity. Histologic examination is no more valuable a source of information about tumors of the thyroid than a complete gross examination. It was demonstrated that all histologic types could be found in the majority of cancers as well as in multiple metastases. From this experience we have developed the following simple classification of cancer of the thyroid gland used in this discussion:
1. Adenocarcinoma
(a) Directly invasive
(b) Lymphatic invasive
(c) Hemangioinvasive
2. Undifferentiated carcinoma
3. Sarcoma
INCIDENCE
In an eight-year period we have done 300 thyroidectomies upon clinically abnormal glands. Thirty-one were cancers, an increase of 10%. The distribution of these is shown in Table 1. We are including for discussion another 20 cancers which have been