[Inflammatory diseases of the thyroid gland]. / Entzündungen der Schilddrüse.

This review article deals with the classification, clinical features and morphology of thyroiditis. These inflammatory diseases account for approximately 20 % of all thyroid diseases. The vast majority of cases of thyroiditis are of immunogenic origin while non-immunogenic thyroiditis (caused by pathogens or iatrogenic) is a rarity.

[De Quervain thyroiditis. Corner points of the diagnosis]. / A szubakut de Quervain-thyreoiditis. A kórismézés sarokpontjai négy eset kapcsán.

Inflammatory disorders of the thyroid gland are divided into three groups according to their duration (acute, subacute and chronic). De Quervain's thyroiditis (also termed giant cell or granulomatous thyroiditis) is a subacute inflammation of the thyroid, which accounts for 5% of thyroid disorders. The etiology is unknown, it usually appears two weeks after an upper viral respiratory infection. The clinical feature includes neck pain, which is aggravated during swallowing, and radiates to the ear. On palpation, the thyroid is exquisitely tender. The erythrocyte sedimentation rate is markedly elevated, the leukocyte count, C-reactive protein are normal or slightly elevated. The natural history of granulomatous thyroiditis involves four phases: the destructive inflammation results temporarily in hyperthyroidism followed by euthyroidism. After a transient hypothyroidism the disease becomes inactive and the thyroid function is normalised. Ultrasonographic findings are diffuse hypoechogenic structures, but nodules may also occur. The disease often remains unrecognised, or the first phase of the disease is diagnosed and treated as hyperthyroidism. The diagnosis can be confirmed by the presence of the thyroid autoantibodies, radioiodine uptake and fine needle aspiration cytology. There is no special treatment, non-steroid anti-inflammatory drugs or steroid should be given to relieve the pain. The aim of the authors is to shed light the key points of diagnosis and differential diagnosis by the presentation of four slightly different cases.

[What diagnosis can be made by the pathologist in a case of sclerosing thyroiditis?]. / Quel diagnostic l'anatomopathologiste peut-il porter en présence d'une thyroïdite sclérosante ?

The pathology of thyroiditis seems well-established with a recognized classification based on clinical and pathological features. However, problems of differential diagnosis remain between both Riedel's and Quervain's thyroiditis and sclerosing Hashimoto's thyroiditis: these entities sometimes lack the characteristic histological pattern, and the clinico-biological data are not always available to the pathologist. We re-examined 18 cases of thyroiditis with sclerosis, retrieved from our files, diagnosed as Riedel's thyroiditis in five cases, Quervain's thyroiditis in five other cases and sclerosing Hashimoto thyroiditis in eight cases. Only two diagnosed cases of Riedel's thyroiditis were pathognomic. Three cases of Quervain's thyroiditis and four cases of sclerosing Hashimoto's thyroiditis presented a slight or moderate extension of the fibrosis in perithyroidal soft-tissues, raising the differential diagnosis of an incipient Riedel's thyroiditis. A definite diagnosis of the type of thyroiditis with sclerosis remains difficult, because all three pathologies present common points. In cases with a characteristic pattern, the diagnosis is straightforward. However, it appears in our study that half of the diagnoses remain ambiguous, because of the existence of histological features common to different entities. In these cases, we think the diagnosis of sclerosing thyroiditis NOS would be more appropriate, the histology not being sufficiently characteristic to make a more specific diagnosis.

Syndromes of thyrotoxicosis with low radioactive iodine uptake.

It is very important to diagnose correctly the etiology of thyrotoxicosis, because the course and treatment of thyrotoxicosis with low radioactive iodine uptake differ significantly from that of hyperthyroidism due to Graves' disease or toxic nodular goiter. Many causes of subacute thyroiditis have been identified producing a characteristic course of transient hyperthyroidism, followed by hypothyroidism, and usually recovery. Ectopic hyperthyroidism includes factitious thyroid hormone ingestion, struma ovarii, and, rarely, large deposits of functioning thyroid cancer metastases. Iodine-induced hyperthyroidism may be associated with low radioiodine uptakes. Amiodarone-associated hyperthyroidism may be the result of subacute thyroiditis or iodine-induced hyperthyroidism; assessment and treatment can be quite challenging.

Nodular thyroid disease and cancer.

Different possibilities of solitary or multinodular involvement of the thyroid gland are described. Because of the broad spectrum of malignancy there exists a controversy and widespread divergence of opinion regarding the incidence, malignancy, classification and treatment of thyroid cancer.