33) In another institution, metastatic disease with cystic foci was seen in patients with synovial sarcoma, hepatocellular carcinoma and insular carcinoma
of the thyroid gland.
Under the malignant category, there were seven cytologically diagnosed cases: four cases of papillary carcinoma, two cases each of anaplastic carcinoma and medullary carcinoma, and a single case of insular carcinoma
Although the differentiation of insular carcinoma from other thyroid carcinomas has important prognostic and therapeutic significance, relatively little about insular carcinoma has been published in the otolaryngology literature.
1) They called this malignancy insular carcinoma based on its distinct microscopic features.
1,7) Some authors have recommended that insular carcinoma be classified as a poorly differentiated thyroid tumor that is less aggressive than undifferentiated or anaplastic thyroid carcinoma, while others have suggested that insular carcinoma is an aggressive variant of a well-differentiated thyroid cancer that manifests insular features.
In this article, we report a new case of insular carcinoma of the thyroid.
of Cases Hyperplastic nodule 1 Goiter 4 Adenoma 3 Hurthle cell adenoma 5 PTC, usual 14 PTC, solid 2 PTC, Warthin-like 1 PTC, follicular variant 15 PTC, tall cell 5 PTC, columnar 1 PTC, diffuse sclerosing 2 PTC, microcarcinoma 2 Metastatic PTC 3 Follicular thyroid carcinoma 3 Hurthle cell carcinoma 8 Poorly differentiated carcinoma 1 Anaplastic carcinoma 2 Insular carcinoma 2 Medullary thyroid carcinoma 1 * PTC indicates papillary thyroid carcinoma.
The second anaplastic and 2 insular carcinomas were nonreactive.
Thus, a carcinoma with predominantly follicular histologic features and a focal insular component was placed among the follicular carcinomas, whereas an insular carcinoma with a focal well-differentiated component was placed in the insular carcinoma category.
As already stated, in addition to the 16 cases of insular carcinoma, there were 25 cases of largely well-differentiated carcinomas (6 follicular, 13 papillary, including the follicular variants, and 6 Hurthle cell carcinoma) that contained poorly differentiated areas at the primary, metastatic, or both sites (Figure 1).
Cases in which the primary tumor was less differentiated included 2 cases each of insular carcinoma and follicular carcinoma and 1 case each of Hurthle cell and anaplastic carcinoma.
Nearly 100% of thyroid carcinomas, including papillary carcinomas, follicular carcinomas, insular carcinomas
, and medullary carcinomas, are positive for TTF1.