Geographic pathology of thyroid diseases

The thyroid is one of the organs which demonstrates clearly the influence of extrinsic and especially geographically determined influences in the development of diseases. Endemic goiter and cretinism are the most typical examples. The question as to whether thyroid cancer arises more frequently in goiters that in normal thyroids, cannot be answered definitely as yet. But without doubt, the relative frequency of different types of thyroid neoplasms in goiter areas is not the same as in region without endemic goiter. The most common type of thyroid carcinoma observed in a nonendemic region is papillary carcinoma. Follicular and anaplastic carcinomas, however, are more often associated with goiter. Under the influence of iodine prophylaxis, the relative frequency of the different types of thyroid carcinoma approaches that of these carcinomas in nongoiter regions. The malignant hemangioendothelioma is observed nearly exclusively in some Alpine goiter areas. Since the introduction of preventive measures in Switzerland, its occurrence has diminished progressively. In contrast to endemic goiter, focal thyroiditis and even Hashimoto's disease seem to be on the increase since institution of iodine prophylaxis of endemic goiter. As the development of malignant lymphoma may be related to thyroiditis, a possible increase of such tumors should be considered.

Non-toxic goitre: diagnostic role of aspiration cytology, antibodies and serum thyrotrophin

Fifty cases of bilateral non-toxic goitre, largely unselected, have been studied using fine needle aspiration cytology (without local anaesthesia); four techniques of thyroid antibody tests; serum thyroid biochemistry (including radioimmunoassay of TSH) and clinical evaluation. Autoimmune thyroiditis was found cytologically in 64%; simple colloid goitre in 24%; subacute thyroiditis of de Quervain in 10%. Aspiration cytology was the most sensitive means of detecting autoimmune thyroiditis and subacute thyroiditis. Two antibodies directed against the intra-cellular cytoplasmic antigen--the complement fixation test and an immunofluorescent antibody were of lesser value in detecting autoimmune thyroiditis (80% positivity) though equal to each other. Serum TSH was of some value--being elevated in 63% of cases of autoimmune thyroiditis and in no cases of simple colloid goitre. Two major cytological subtypes of autoimmune thyroiditis have been described--with significant differences in duration of goitre, mode of presentation, frequency of hypothyroidism, and response to thyroxine therapy. The high frequency of autoimmune thyroiditis in this series suggests that endemic goitre is unlikely in Western Australia.

Kentucky Appalachian goiter without iodine deficiency. Evidence for evanescent thyroiditis

In Breathitt County, Kentucky, an Appalachian Mountain community, 1,267 children were examined to determine goiter prevalence. Matched pairs of 82 goitrous and nongoitrous children were reexamined six months later for family history, urinary iodine excretion, serum thyroxine, triiodothyronine, protein-bound iodine, thyrotropin, and thyroid autoantibodies. Goiter prevalence was 8.4%. Iodine deficiency was not found. Thyroid stimulating hormone levels were higher in the goitrous group. Microsomal autoantibody titers were elevated in 20% of the children with goiters vs 6% of controls (P less than .05). Fluorescent antibodies were associated with positive microsomal (P less than .01) but not with positive tanned RBC autoantibodies. Unexpectedly, on repeat examination, goiter was absent in 17 (21%) of the originally goitrous group, but was now present in 22 (25%) of the controls. We concluded that while evolving thyroiditis is common in Appalachian children, it does not explain all goiters in an area of abundant iodine intake and known familial goiter.

Thyroid and other autoantibodies in British and Japanese women: an epidemiological study of breast cancer

To define the role of asymptomatic autoimmune thyroiditis in the cause of breast cancer, the presence of circulating thyroid autoantibodies was studied in two populations, one with a high risk of breast cancer (British women) and one with a low risk (Japanese women). Ostensibly healthy women and patients with breast cancer from both countries were studied. There was no difference in the incidence of thyroid autoantibodies between women with breast cancer and healthy women in either race. The incidence of thyroid autoantibodies in healthy British women, however, was two to three times that in healthy Japanese women. The incidence of reticulin antibodies, was considerably higher in both groups of Japanese women. No remarkable differences in the incidence of antinuclear, smooth-muscle, antimitochondrial, gastric parietal cell, or liver-kidney microsomal antibodies were found between women with breast cancer and healthy women or between the two races. Only the incidence of antinuclear antibodies was marginally higher in Japanese patients with advanced cancer. These results indicate that asymptomatic autoimmune thyroid disease is more prevalent among British than among Japanese women, but they fail to provide direct evidence that autoimmune thyroid disease is associated with breast cancer. Prospective studies of women with autoimmune thyroiditis and studies of young women from low-risk and high-risk populations are needed.

Spontaneous autoimmune thyroiditis in the BUF rat

The inbred BUF rat develops autoimmune thyroiditis spontaneously. The incidence is related to the age of the animal and is increased by neonatal thymectomy and by treatment with methylcholanthrene. Autoantibodies to thyroglobulin can be demonstrated by indirect immunofluorescence and hemagglutination, but skin tests are negative. The "spontaneous" autoimmune disease may be due to the conjunction of an unusually vigorous immunological response to thyroglobulin and the loss of thymic suppressor function.

Thyroid nodules and thyroid carcinoma

Seventy carcinomas of the thyroid gland were found in 1300 thyroidectomies for an incidence of 5.4%. The incidence of malignancy in single nodules was 9.7% and in multinodular nontoxic goiter 4.3%. The risk of cancer was higher (14.2%) in males than in females (4.3%). The highest incidence of cancer was found in children under the age of 10 (40%). Radioactive iodine scintiscanning was of limited help in differentiating benign from malignant nodules. Early surgery is advised for all patients with single thyroid nodules and all thyroid nodules in children should be excised.

Exophthalmus-myxoedema circumscriptum praetibiale-osteoarthropathia hypertrophicans (E.M.O.) syndrome in Graves' disease: a review of eight cases reported in Japan

Case 1 showed recurrence of hyperthyroidism accompanied by pretibial myxedema and digital clubbing 14 years after thyroidectomy for Graves' disease. Case 2 had had pretibial myxedema for the past 20 years and myxedema tuberosum at the right shoulder for the past 10 years, and on admission showed exophthalmos and digital clubbing with thyroid gland demonstrating histological picture of chronic thyroiditis. This case was in slight hypothyroidism and serum LATS was highly positive. Eight cases of E.M.O. syndrome have so far been reported in Japan, including our own. Six cases of these were males. Two cases did not show any sign of hyperthyroidism throughout their entire courses, including our Case 2 described here. Three cases had never received treatment for Graves' disease prior to the occurrence of this syndrome. The serum LATS was positive in all 5 cases thus far reported.

The single thyroid nodule and carcinoma

A review of 568 cases of single thyroid nodule operated upon during the period 1960–72 is presented.

Females were more frequently affected than males, the ratio being 8.6:1. The right lobe was more frequently involved (57.6 per rent) than the left. The nodules in our series were classified according to the scintiscan findings as follows: cold 466 cases (82 per cent), warm 32 cases (5.6 per cent) and hot or toxic 70 cases (12.4 per cent). The incidence of carcinoma was 12 per cent and 6.2 per cent in cold and warm nodules respectively. No malignancy was found in either hot nodules or toxic adenomas. The incidence of carcinoma was higher in male patients and significantly higher in patients of over 60 years.