Benign Follicular Adenoma Research Articles

A CASE REPORT OF MEDIASTINAL GOITER WITH SUPERIOR VENA CAVAL SYNDROME

A 61-year-old male was admitted to the hospital because of swelling of his right upper limb. Chest X-ray and CT scan revealed an intramediastinal tumor which connected to the struma of right lobe of the thyroid. Venography revealed a narrow right brachio-cepharic vein, which was remarkably compressed by the tumor. The patient was diagnosed as having a mediastinal goiter with superior vena caval syndrome. The 11×7×7cm tumor, which was adhered to the right brachio-cepharic vein, was safely resected under collar incision of the neck and median sternotomy. The pathological diagnosis was benign follicular adenoma. After the operation the swelling sensation of the right upper arm disappeared. Mediastinal goiter is relatively rate. This case of the disease described here appears rare in that benign mediastinal goiter compressed the right brachiocepharic vein to present superior vena caval syndrome.

Activation of the ret oncogene in human thyroid carcinomas

A novel oncogene has been recently found activated in human thyroid carcinomas. This oncogene was named RET/PTC and was shown to be a chimeric gene, product of the fusion of the tyrosinekinase domain or the RET proto-oncogene to the 5’-terminal region of another gene named H4 or D10S170. A paracentric inversion (10) (q 11.2-21) was demonstrated to be responsible for the H4/RET fusion. Thyroid tumors consist of a broad range of lesions ranging from the benign follicular adenomas to the differentiated papillary and follicular carcinomas and to the fatal anaplastic carcinomas. Papillary and follicular carcinomas have different clinical behaviours and are associated with different risk factors, thus they are probably related to different genetic events. In fact the activation of RET is restricted to the papillary subtype. Here we show the activation of the RET oncogene in 2 out of 10 new cases of papillary thyroid carcinomas.

HLA class II antigen expression and the autoimmune thyroid response in patients with benign and malignant thyroid tumors

To further understand the relationship between the immune system and the neoplastic human thyroid cell we investigated the degree of intrathyroidal lymphocytic infiltration and thyroid HLA class II expression in 17 patients with thyroid tumors. In another 60 thyroid tumor patients the association of thyroidal lymphocytic infiltration with thyroid autoantibody production was analyzed. In total 117 thyroid tissues were examined including tissue obtained at autopsy ( n = 28), fetal thyroid tissue ( n = 4), thyroid samples obtained from areas distant from benign follicular adenomas ( n = 5), and 80 abnormal thyroids including patients with benign ( n = 53) or malignant ( n = 24) thyroid tumors and Hashimoto's thyroiditis ( n = 3). Normal adult and fetal thyroid tissue had no significant lymphocytic infiltration and no detectable HLA-DR, -DP, or -DQ antigens on their thyroid follicular epithelial cells. The degree of lymphocytic infiltration in the nonneoplastic thyroid tissue of thyroid glands with benign and malignant thyroid tumors varied considerably and correlated with the presence and titer of serum thyroid autoantibodies measured by sensitive ELISA techniques. However, all but one of the benign follicular adenomas had thyroid cells negative for HLA class II determinants despite the presence of infiltrating lymphocytes, while 7 of 10 thyroid carcinomas expressed class II antigen (principally HLA-DR) even when only minor degrees of lymphocytic infiltration were present. These data indicate a correlation between lymphocytic infiltrates and serum thyroid autoantibody titers but the relationship with HLA class II expression is more complex. Since we have previously shown that HLA class II antigen expression can be induced by local interferon-γ secretion, presumably from activated T cells, we conclude that estimates of simple thyroid lymphocytic infiltration and serum autoantibody secretion do not correlate with the degree of intrathyroidal T-cell activation. Furthermore, our observation of increased expression of HLA class II antigens in thyroid cancer suggests considerable cellular heterogeneity in susceptibility to HLA class II antigen induction in human thyroid disease.

18F-fluorodeoxyglucose imaging in preoperative diagnosis of thyroid malignancy.

Fourteen human thyroid tumors were studied with 18F-fluorodeoxyglucose (FDG) imaging. The proliferative activity and DNA ploidy of the tumors was assessed by DNA flow cytometry. FDG accumulated in a Hürthle cell carcinoma, an anaplastic carcinoma and a thyroid lymphoma, but only slightly or not at all in the three papillary carcinomas studied. Three of the eight benign tumors also accumulated FDG, but two of these were selected for imaging because of a large number of proliferating cells in DNA flow cytometry. Two carcinomas with increased nuclear DNA content retained FDG, but a histologically benign follicular adenoma with DNA aneuploidy did not. We conclude that in addition to malignant thyroid tumors, histologically benign tumors may also accumulate FDG, and therefore the value of FDG scanning in the preoperative diagnosis of thyroid malignancy is limited.

MR Imaging of the Thyroid

Spin-echo magnetic resonance (MR) imaging of the thyroid gland was performed in patients using a superconducting magnet operating at 0.35 T. There were 17 women and two men with an age range of 21-77 years. All of the patients with disease were also evaluated with scintigraphy and three of the four subjects with normal thyroid glands also had scintigraphy. Final diagnoses in the patients were normal gland in four, Graves disease in two, thyroid cyst in one, benign follicular adenoma in two, papillary cell carcinoma in one, Hürthle cell carcinoma in one, Hashimoto thyroiditis in one, and multinodular goiter in seven. The normal thyroid and surrounding anatomy were clearly demonstrated by intrinsic signal intensity differences of the tissues. The thyroid gland in Graves disease was enlarged and had homogeneously increased signal intensity at all pulse sequences compared with skeletal muscle and normal thyroid. The thyroid cyst and benign adenoma were well defined; however, the cyst displayed the greater signal intensity on more T2-weighted pulse sequences. The MR signal intensity features of multinodular goiter and Hashimoto thyroiditis appear similar to those of the normal gland. In cases of focal masses, MR could not reliably distinguish benign from malignant tumor. However, using intensity ratio data there was a statistically significant difference between solid and hemorrhagic cystic disease.

Solitary thyroid nodule

The approach to management of an isolated thyroid nodule requires some understanding of the natural history of thyroid cancer and other forms of nodular thyroid disease. The histologic classification of thyroid cancer is an important determinant of survival, as are the size of the primary tumor, presence of thyroid capsule invasion, and presence of distant metastases. Therapeutic radiation and radioactive fallout increase the risk that a thyroid nodule is malignant. Autonomously functioning thyroid nodules are usually benign follicular adenomas and may cause thyrotoxicosis.