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PubMed1975

The influence of preoperative drug treatment on the extent of hyperplasia of the thymus in primary thyrotoxicosis.

Thymic biopsies taken from women at the beginning of the operation of subtotal thyroidectomy were studied by the point-counting histometric technique. In all patients with primary thyrotoxicosis, the thymus is hyperplastic. After pretreatment with antithyroid drugs, the pattern of thymic involution with age is similar to, but at higher levels, than that in control groups of patients with non-toxic goitre in whom there is no evidence of immunological abnormality. By contrast, after propranolol pretreatment very little age involution is seen. The differences in the appearance of the thymus in female primary thyrotoxixosis patients prepared for operation with different drug treatment regimes are probably related to the pharmacological actions of the drugs and may indicate an interaction between primary immunological and secondary endocrinological factors in the disease process.

Adolescent↗
PubMed1997

[Reactive thymus dysplasia following therapy for ACTH-producing tumors].

UNLABELLED: Surgical or conservative treatment of ACTH-producing tumors results in acute drop of the previously excessively high cortisol levels. The following associated pathophysiological changes also occur in the organism's recovery from stress, such as trauma, operation or chemotherapy of tumors. Both cases result in a regeneration of the immune system, which might even be exalted. The corresponding radiographic feature is the "rebound" enlargement of the thymus occurring about six months after remission of hypercortisolism. Histological examination reveals benign thymus hyperplasia. Especially in cases of still unknown primary tumor the appearance of this anterior mediastinal mass can lead to misdiagnosis. We present the cases of two patients with diffuse thymic hyperplasia following surgical and medical correction of hypercortisolism. One patient suffered from classic Cushing's disease responding to transsphenoidal resection of an ACTH-secreting pituitary microadenoma. Six months later CT of the chest incidentally demonstrated an anterior mediastinal mass known as thymic hyperplasia. The second patient presented with an ectopic, still unkown source of ACTH-production. Six months after medical correction of hypercortisolism CT of the thorax showed an enlargement of the anterior mediastinum. Thymectomy was performed in order to exclude thymus carcinoid. Histological examination revealed benign thymus hyperplasia with negative immunostaining. CONCLUSION: Radiologists and clinicians should be familiar with the pathophysiological changes resulting from precipitously dropping cortisol levels in order to prevent diagnostic errors and unnecessary operations.

Adrenocortical Hyperfunction↗
PubMed2005

Thymus alterations and systemic sclerosis.

OBJECTIVES: The pathogenesis of systemic sclerosis (SSc) includes complex alterations to the immune system, possibly responsible for diffuse microvasculature and fibroblast dysfunction. Previous anecdotal observations suggest a possible role for thymus alterations in some autoimmune rheumatic diseases, including SSc. This study aimed to investigate the prevalence of radiological thymus alterations in SSc patients. METHODS: Thirthy-four unselected patients [28 female and 6 male, mean age (+/- S.D.) 49.7 +/- 9.5 yr, range 33-67 yr] and 34 age- and sex-matched controls were included in the study. The presence of major radiological thymus alterations, i.e. an abnormally enlarged or nodular thymus, were blindly investigated by means of unenhanced multidetector computed tomography. RESULTS: Abnormally enlarged or nodular thymuses were detected in a statistically significant percentage of SSc patients compared with controls (21 vs 0%, P = 0.011). More interestingly, radiological thymus alterations were invariably observed in patients with shorter disease duration (< or =5 yr, 41% vs >5 yr, 0%; P = 0.007), frequently associated with serum anti-Scl70 antibodies (P = 0.017). Among patients with thymus alterations one developed myasthenia gravis while two others showed thymus hyperplasia at histopathological evaluation after thymectomy. CONCLUSIONS: The present study suggests a possible role of thymic disorders, mainly thymus hyperplasia, in a significant number of SSc patients. Due to the limitations of radiological evaluation, the actual relevance of such an association might be underestimated. The relationship of thymus alterations with shorter disease duration, as well as with serum anti-Scl70, suggests that thymic dysfunction could play a pathogenetic role mostly in the early phases of the disease, and possibly in specific SSc patient subsets.

Adult↗
PubMed1976

Genetic associations between myasthenia gravis and the HL-A system.

HL-A antigens were determined in 159 myasthenic patients, 112 of whom were females and 47 males. Fifty-seven patients were thymectomized. The relationship between 23 different HL-A antigens and myasthenia gravis (MG) with reference to sex, age at onset, clinical course of MG, thymus histology, and auxiliary diseases of the patients, as well as the significance of these antigens to 245 relatives of myasthenics, were analysed. The frequencies of HL-A1 and HL-A8 were highly significantly higher in myasthenic patients than in normal Finnish controls. The increase of HL-A1 is secondary and due to a strong linkage disequilibrium between HL-A8 and HL-A1. HL-A8 appeared most often in females with onset of MG before the age of 35 years, and inpatients with thymus hyperplasia. No significant HL-A deviations were found in males or in females with later onset of disease. In seven thymoma patients the occurrence of W10 antigen was almost significantly increased.

Autoimmune Diseases↗
PubMed1992

Myasthenia gravis muscle antibodies examined by ELISA: IgG and IgM antibodies characterize different patient subgroups.

Sera from 90 myasthenia gravis (MG) patients were examined for antibodies against skeletal muscle citric acid extract (CA) antigens by ELISA and indirect haemagglutination (IHA). 31% (ELISA) and 24% (IHA) of the sera were positive, and the results of the two tests were in good agreement. 18 of 28 patients positive in ELISA had IgG CA-antibodies, 10 had IgM and 3 IgA CA-antibodies. The patients with IgG antibodies had a high mean age of MG disease onset, and 9/14 thymectomized patients had a thymoma. Patients with IgM CA-antibodies had a much lower age of onset and 4/5 thymectomized patients had thymus hyperplasia. IgM antibody positive patients had a long disease duration, indicating that they produce IgM antibodies for an indefinite period of time without switching to IgG antibody production.

Adolescent↗
PubMed1983

[Mediastinal tumors: pathology--a contribution to classification and prognosis].

Basing on 161 mediastinal tumours (thymomas, thymolipomas, thymus carcinoids, neurogenic and histiocytic tumours, malignant lymphomas) and tumour lesions (lymphofollicular thymus hyperplasia, known as Castleman's lymphoma), the article discusses problems of classification, differential histology and prognosis (taking staging groups and tumour-associated syndromes into consideration). The conventional light microscopic methods are often insufficient to accurately classify a specific tumour. The repertoire of morphological methods has in recent years been significantly extended by immunohistological methods. The use of these diagnostically very efficient methods, however, requires close interdisciplinary co-operation (e.g. in special fixation methods) between those competent for diagnosis and for therapy.

Adult↗
PubMed1988

[Computed tomographic findings in 36 patients with space-occupying lesions of the thymus].

The CT examination of 36 patients with masses in the thymus (three thymus hyperplasias, 33 thymomas) were evaluated retrospectively. Three tumours in atypical positions posed problems in differential diagnosis from bronchial carcinomas and two cases with extensive pleural metastases had to be differentiated from pleural mesotheliomas. There were no certain morphological features on CT which indicated whether the mass was malignant. Eleven patients with thymomas had metastases; in seven of these they were extra-thoracic, with preference for supraclavicular lymph nodes, adrenals and the axial skeleton. Tumour progression and distant metastases were found particularly in malignant thymomas of the epithelial type. Calcification in a thymoma tends to indicate that it is malignant.

Adolescent↗