MALT lymphoma of the thymus with Sj?gren’s syndrome: biphasic changes in serological abnormalities over a 4-year period following thymectomy

Thymic mucosa-associated lymphoid tissue (MALT) lymphoma shows distinct immunological characteristics, such as the expression of the IgA isotype, the frequent presence of immunoglobulin abnormalities, and a strong association with autoimmune disease, especially Sj?gren’s syndrome (SjS). We report a case of thymic MALT lymphoma, who exhibited biphasic changes in her clinical characteristics during the 4-year observation period after thymectomy. A 71-year-old woman was admitted because of suspected SjS. A diagnosis of primary thymic MALT lymphoma was made, and SjS was confirmed. Serological abnormalities such as polyclonal hypergammaglobulinemia, IgA M protein, and elevated levels of rheumatoid factor were noted. These abnormalities improved rapidly after the thymectomy, but did not completely disappear. Interestingly, the remaining abnormalities, which can be ascribed to the proliferation of B cells throughout the body under the influence of SjS, have been improving slowly but steadily during the 4-year observation period. It is suspected that the removal of the tumor by thymectomy has more or less normalized the immunological environment and alleviated the SjS disease activity.     

MYASTHENIA GRAVIS : CLINICAL,SEROLOGICAL AND HISTOLOGICAL STUDIES IN RELATION TO THYMECTOMY

In 10 cases of myasthenia gravis correlative studies were made by means of autoimmune serological tests, electromyography, thymic X-ray examination (pneumomediastinography) and assessment of thymic morphology in relation to the effects of thymectomy (nine cases) and thymic irradiation (one case). The 10 patients were placed in three groups, namely (a) three young females with a non-involuted thymus showing “thymitis” and negative results to serological tests who derived benefit from thymectomy, (b) four older females with thymic atrophy and positive results to serological tests who for the most part gained no benefit from thymectomy, and (c) three males with thymomas and positive results to serological tests who obtained benefit from thymectomy in two instances. The presence of the characteristic autoantibody—the myoid antibody which reacted with thymic myoid cells and skeletal muscle—was helpful in diagnosis but did not appear to be related to neuromuscular block, neither was it of value in predicting the response to thymectomy. Electromyography with the decamethonium test showed, with one exception, the characteristic myasthenic responses irrespective of the patient's age, the presence or absence of myoid antibody, or the nature of the microscopic lesion in the thymus. The radiographic outline of the thymus as determined by pneumomediastinography correlated well with the size and shape of the resected thymus. The typical histological appearance in the thymus of abundant cortex and prominent medullary germinal centres and lymphocytosis was termed “thymitis” ; it was characteristic of the thymus of patients in group (a) and the residual thymus of patients with thymoma in group (c). Our clinical observations could be correlated with experimental studies, indicating that myasthenia gravis is associated with a destructive “autoimmune thymitis”. It is suggested that “thymitis” is associated with the release from the medulla of an uncharacterized humoral agent which causes neuro-muscular block.     

THE THYMUS: EXPERIMENTAL PHYSIOLOGY,AND PATHOLOGY IN MAN

The thymus is an integral part of the immunological system. It is a site of intense lymphopoiesis, especially in early life. Neonatal thymectomy in mice causes runting and death due to gross immunological deficiencies. These deficiencies are determined by lymphopenia, and by lack of a lymphotrophic hormone secreted by the epithelial cells of the medulla; this hormone confers on lymphocytes the capacity to respond to antigenic stimulation. The thymus may be the main source of lymphoid cells carrying new or primary patterns of immune reactivity; it is thus “first-level” or “central” lymphoid tissue, which seeds cells to “second-level” or “peripheral” lymphoid tissues in the lymph nodes and spleen. Pathological lesions of the thymus in man include aplasia, hyperplasia, dysplasia and neoplasia. Gross aplasia characterizes the immunological deficiency diseases of infancy, including the lymphopenic type of congenital agammaglobulinæmia. Hyperplasia accompanies thyrotoxicosis. Dysplasia refers to the lymph follicle-germinal centre development in myasthenia gravis, probably an autoimmune disease, and to the proliferation in the medulla of spindle-epithelial cells in lupus erythematosus, an autoimmune disease. Neoplasia occurs as benign thymoma, which may be accompanied by extrathymic diseases which are possibly autoimmune in origin; these include myasthenia gravis, red cell aplasia, polymyositis, agammaglobulinæmia and lupus erythematosus. These diseases may in some way be caused by the thymoma; alternatively, the thymoma may represent the result of continuing hyperplasia of the thymus provoked by a primary autoimmune process. The place of thymectomy in the treatment of autoimmune disease is discussed. It is an established procedure in myasthenia gravis, and has been successful in two cases of autoimmune hæmolytic anæmia in infancy. We review our experience with thymectomy for three patients with systemic lupus erythematosus.     

Unusual remnant thymic tissue in an adult mimicking malignant neoplasm: escape from age-related involution

Here we report on a 55-year-old man with an abnormal anterior mediastinal shadow and multiple nodules in the thymus, which increased in size over a period of 15 months. He was diagnosed with early prostatic cancer, and treated with chemotherapy. Although no definite preoperative diagnosis was obtained, surgery was performed because of the possibility of malignant neoplasm or metastasis. Extended thymectomy was performed and pathological examination revealed that the nodules were remnant thymic tissue and not malignant lesions. Although the cause of this unusual remnant thymic tissue remains unclear, it may have been related to autoimmune or endocrinological disease.     

Thymus abnormalities in ulcerative colitis —comparative study with other autoimmune diseases

Since the thymus is thought to play an important role in the pathogenesis of ulcerative colitis, thymic abnormalities were studied on 18 cases of ulcerative colitis by using pneumomediastinography and histopathological examination. We have compared the thymic abnormality of ulcerative colitis with that of 104 cases of variety of autoimmune diseases. The denser and larger thymic shadow was seen in ulcerative colitis and this finding was same as in other autoimmune diseases. But the thymic size in ulcerative colitis was the largest in all examined autoimmune diseases.     

A case of dermatomyositis with “liver disease associated with rheumatoid diseases” positive for anti-liver–kidney microsome-1 antibody

We reported a case of dermatomyositis (DM) with liver disturbance in a 50-year-old Japanese female. She presented with fever, muscle weakness, and typical DM rashes. On clinical and serological examinations, the liver impairment was initially diagnosed as probable autoimmune hepatitis, which was denied by a histological study despite positive anti-liver–kidney microsome-1 antibody. Finally, she was diagnosed as having DM with “liver disease associated with rheumatoid diseases”, and treatment with oral prednisone (40 mg/day) achieved normalization of liver and muscle enzyme levels as well as improvement of symptoms associated with DM. Liver involvement in patients with polymyositis (PM)/DM has not been well described and is considered to be uncommon. Full clarification of the etiology of liver impairment with a histological examination in collagen diseases including PM/DM is useful to determine the proper dose of corticosteroids for the treatment of collagen diseases and their liver complications.     

Thymic histology in myasthenia gravis.

Histological features of resected thymuses of 18 patients with myasthenia gravis were evaluated. Thymoma were seen in 16.6% of the patients. In the non-thymomatous group, thymic hyperplasia with follicle formation was seen in 33.3%, involuted thymus with occasional lymphoid follicle formation in 11.1%, thymitis with B cell infiltration in 16.6%, involuted thymus in 11.1% and normal thymus in 11.1% of patients. Immuno-histological staining for B and T lymphocytes delineated the group labelled as thymitis with B cell infiltration. Mast cell and eosinophils were frequently seen in thymuses with thymic hyperplasia with follicle formation and thymitis with B cell infiltration. Thymic hyperplasia with follicle formation was more frequent in young patients and these patients had better prognosis.     

Rationale for bone marrow transplantation in the treatment of autoimmune diseases.

Transplantation of normal bone marrow from C3H/HeN nu/nu (H-2k) mice into young MRL/MP-lpr/lpr (MRL/l; H-2k) mice (less than 1.5 mo) prevented the development of autoimmune diseases and characteristic thymic abnormalities in the recipient mice. When female MRL/1 (greater than 2 mo) or male BXSB (H-2b) mice (9 mo) with autoimmune diseases and lymphadenopathy were lethally irradiated and then reconstituted with allogeneic bone marrow cells from young BALB/c nu/nu (H-2d) mice (less than 2 mo), the recipients survived for more than 3 mo after the bone marrow transplantation and showed no graft-versus-host reaction. Histopathological study revealed that lymphadenopathy disappeared and that all evidence of autoimmune disease either was prevented from developing or was completely corrected even after its development in such mice. All abnormal T-cell functions were restored to normal. The newly developed T cells were found to be tolerant of both bone marrow donor-type (BALB/c) and host-type (MRL/1 or BXSB) major histocompatibility complex (MHC) determinants. Therefore, T-cell dysfunction in autoimmune-prone mice can be associated with both the involutionary changes that occur in the thymus of the autoimmune-prone mice and also to abnormalities that reside in the stem cells. However, normal stem cells from BALB/c nu/nu donors can differentiate into normal functional T cells even in mice whose thymus had undergone considerable involution, as in the case of BXSB or MRL/1 mice in the present studies. These findings suggest that marrow transplantation may be a strategy ultimately to be considered as an approach to treatment of life-threatening autoimmune diseases in humans. T-cell dysfunction in autoimmune-prone mice previously attributed to involutionary changes that occur in the thymus of these mice may instead be attributed to abnormalities that basically reside in the stem cells of the autoimmune-prone mice.     

Autoimmune thrombocytopenic purpura, autoimmune hemolytic anemia and gastric cancer appeared in a patient with myasthenia gravis

We report a case of myasthenia gravis (MG) associated with autoimmune thrombocytopenic purpura (AITP) and autoimmune hemolytic anemia (AIHA), and after that gastric cancer appeared. A 51-year-old man began to suffer from fluctuated muscle weakness in 1985. Muscle weaknesses became exacerbated, and he was admitted to our hospital in 1989. He was diagnosed as MG associated with AITP. After a thymectomy (hyperplasia), prednisolone therapy was started, subsequently his condition was satisfactory. In March 1995, he developed severe anemia and icterus. He was diagnosed as Evans' syndrome (AIHA and AITP) with MG. High-doses of immunoglobulin administration improved the anemia, but thrombocytopenia continued. In November 2002, he suffered marked petechia; the platelet count decreased to 1000/microl. Methylprednisolone pulse therapy and platelet transfusion were started. Gastrofiberscopy was performed and biopsy specimens revealed signet cell-type adenocarcinoma. On December 19, 2002, subtotal gastrectomy and splenectomy were performed. After that, his condition has remained satisfactory, without MG symptoms or thrombocytopenia. This is the first such case report in the literature.     

Thymus and aging: morphological, radiological, and functional overview

Aging is a continuous process that induces many alterations in the cytoarchitecture of different organs and systems both in humans and animals. Moreover, it is associated with increased susceptibility to infectious, autoimmune, and neoplastic processes. The thymus is a primary lymphoid organ responsible for the production of immunocompetent T cells and, with aging, it atrophies and declines in functions. Universality of thymic involution in all species possessing thymus, including human, indicates it as a long-standing evolutionary event. Although it is accepted that many factors contribute to age-associated thymic involution, little is known about the mechanisms involved in the process. The exact time point of the initiation is not well defined. To address the issue, we report the exact age of thymus throughout the review so that readers can have a nicely pictured synoptic view of the process. Focusing our attention on the different stages of the development of the thymus gland (natal, postnatal, adult, and old), we describe chronologically the morphological changes of the gland. We report that the thymic morphology and cell types are evolutionarily preserved in several vertebrate species. This finding is important in understanding the similar problems caused by senescence and other diseases. Another point that we considered very important is to indicate the assessment of the thymus through radiological images to highlight its variability in shape, size, and anatomical conformation.     

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.     

Malignant thymoma associated with myasthenia gravis, Graves' disease, and SIADH

Patients with thymoma are likely to present with associated autoimmunologic disorders. The occurrence of syndrome of inappropriate antidiuretic hormone (SIADH) attributable to thymoma is extremely rare. We herein present an extremely rare case of a 59-year-old man patient who was discovered to have malignant thymoma associated with myasthenia gravis, Graves' disease, and SIADH. He was admitted for evaluation and treatment of hyponatremia (Na 125 mEq/l). SIADH was diagnosed, and thymoma was identified as its cause. The patient was also found to have both Graves' disease and myasthenia gravis. The hyponatremia was normalized with water restriction and 3% saline therapy before thymectomy. The thymic tumor was a Masaoka stage III thymoma that resulted in direct invasion to the wall of the innominate vein, but there was no finding of invasion to other mediastinal organs. Complete thymectomy with innominate vein graft was performed. Microscopic histopathology findings corresponded to those of a mixed-type thymoma and type B2. However, immunohistochemical stain for antidiuretic hormone was negative in the tumor cells. Adjuvant radiation therapy was employed postoperatively, and the patient's postoperative recovery was uneventful. He subsequently reached a euthyroid state. And the reversal to normal sodium and osmolality levels was continued after the tumor removal without any further management for hyponatremia. The observation of this interesting case and a literature review provided us with the opportunity to explore the pathogenesis and clinical aspects of thymoma-related autoimmune and/or endocrine disorders which must be suspected in patients with thymoma.     

Pneumomediastinum in dermatomyositis itself is not a poor prognostic factor: report of a case and review of the literature

We describe a 38-year-old man who presented with proximal muscle weakness, myalgia, polyarthralgia, and skin rash and was diagnosed as having dermatomyositis (DM). The patient's symptoms improved with prednisolone therapy. However, myopathy relapsed and pneumomediastinum with subcutaneous emphysema developed. Pneumomediastinum with subcutaneous emphysema rapidly disappeared by the administration of ciclosporin. We reviewed the present case and previously reported cases regarding the clinical characteristics. All of the reported death cases were accompanied by interstitial lung disease (ILD). Although it has been reported that pneumomediastinum in DM can be fatal, the direct cause of patient's death was due to respiratory failure resulting from progressive ILD. Pneumomediastinum without ILD shows a good prognosis.     

The phenotype of lymphoid cells and thymic epithelium correlates with development of autoimmune insulitis in NOD in equilibrium with C57BL/6 allophenic chimeras.

The mechanisms contributing to the development of autoimmune insulin-dependent diabetes mellitus have been analyzed in allophenic mouse chimeras of the NOD in equilibrium with C57BL/6 strain combination (where NOD is nonobese diabetic). Occurrence of lymphoid cell infiltration (insulitis) in pancreatic islets was observed in the majority of such chimeras. The development of insulitis was found to correlate with major histocompatibility complex chimerism in lymphoid cells and in thymus cortical regions. Chimeras with more than 50% of C57BL/6 lymphoid cells rarely developed insulitis. Our data suggest that the correlation with the thymic cortical region is absolute. Thus, all individuals displaying NOD or NOD/C57BL/6 thymic cortical regions developed insulitis, whereas we have not observed insulitis in chimeras with only C57BL/6 thymic cortical regions. Thus the positive selection of T cells appears to play a crucial role in the development of insulin-dependent diabetes mellitus.     

The thymus and blood

The thymic epithelium educate the pre-T lymphocytes from bone marrow by either direct contact or humoral stimulation and support their differentiation, proliferation and maturation. Thymic abnormalities include pathological involution, germinal center formation and tumor. Historically, many disorders associated with thymic abnormality have been reported. In this lecture, the structures and functions of human thymus, and immunological and hematological disorders related to thymic abnormalities such as myasthenia gravis, pure red cell aplasia, immunodeficiency syndromes, immunoglobulin dyscrasias, acute T cell-leukemia, Hodgkin disease and lymphocytic lymphoma were reviewed. These extensive reviews suggested "Pharyngeal Pouch Syndrome" and it's significant roles in hematology.     

Computed tomography and pathologic correlations of thymic lesions

Computed tomographic and pathologic correlations of the thymus gland were assessed in 69 patients. The sensitivity of computed tomography (CT) for undifferentiated thymic pathology is 87.1%; the specificity is 85.7%. The sensitivity of CT for neoplasm or mass is 97.1%, the specificity is 97.1%. The sensitivity of CT for lymphoid follicular hyperplasia (LFH) is 71.4%, the specificity is 97.6%. Therefore, a normal-sized thymus gland on CT does not exclude LFH. Completely preserved fat planes between thymic mass and adjacent structures on CT usually indicate a benign (noninvasive) neoplasm; completely absent fat planes usually indicate a malignant (invasive) neoplasm; partially preserved fat planes are indeterminate in assessing invasiveness. CT is also useful in showing recurrence or remnants of thymic tissue in patients who have had a previous thymectomy.     

Dermatomyositis associated with hepatitis B virus-related hepatocellular carcinoma

Dermatomyositis (DM) is an idiopathic inflammatory myopathy (IIM) with typical cutaneous manifestations. It has been proposed that DM may be caused by autoimmune responses to viral infections, and previous studies have also shown that an association between DM and malignancy. However, chronic hepatitis B virus (HBV) infection associated with DM and hepatocellular carcinoma (HCC) is rarely encountered. The authors report a case of DM and HCC in a patient with a HBV infection. A 58-year-old man presented erythematous skin rashes on a sun-exposed area of 2 year’s duration, and recent proximal muscle weakness. His medical history revealed that he had a chronic HBV infection. A diagnosis of DM relies on proximal muscle weakness, elevated muscle enzymes, myopathic changes (demonstrated by electromyography), muscle biopsy evidence of myositis, and its characteristic cutaneous findings. A Liver mass in the left lobe visualized by abdominal computed tomography was confirmed histologically as HCC. This case suggests that DM associated with HCC might be caused by a HBV infection.     

Relapse of autoimmune hemolytic anemia in Evans syndrome after thymectomy for pure red cell aplasia

A 81-year-old woman was referred to our hospital with pure red cell aplasia (PRCA) associated with a thymoma in May 2005. She had previously suffered from Evans syndrome which had been improved by prednisolone in 1999. She underwent a thymectomy, however her anemia subsequently got worse. Reticulocytopenia was noted and a marrow erythroid series was aplastic. Furthermore, both direct and indirect Coombs tests were positive, and the serum haptoglobin level was low. Based on these findings, the patient was diagnosed as having PRCA complicated with relapsed autoimmune hemolytic anemia (AIHA). The PRCA and AIHA were successfully treated with prednisolone and cyclosporine. To our knowledge, only one case of the PRCA complicated with AIHA after thymectomy has been reported. FoxP3 positive regulatory T-cells (Treg), which maintain immunological self-tolerance, were readily detectable in the excised thymoma. Thus, thymectomy resulted in removal of the Treg pool and might explain the autoimmune activation, believed to be one of the mechanisms of the post-thymectomy recurrence of the AIHA in this case.     

Anti-MDA5 antibody dermatomyositis-associated rapidly progressive interstitial lung disease patient complicated with mixed connective tissue disease: A case report

Anti-MDA5 antibody dermatomyositis (DM) is a special type of myositis, which can potentially cause rapidly progressive interstitial lung disease (RP-ILD). Mixed connective tissue disease (MCTD) is a complex disease with different characteristics of autoimmune connective tissue disease, associated with ILD. Both are rare diseases, and few patients with both diseases have been reported. A 71-year-old woman complained of palpitations, with a 2 months history of rash around her hands, extensor surface of right elbow, and the nape of her neck. Subsequently, the patient had acute exacerbation of dyspnea and tachypnea. Anti-Ro52, U1 RNP and MDA5 antibodies were positive; the presenting evidence was suggestive of anti-MDA5⁺DM-RP-ILD complicated with MCTD. Our patient deteriorated rapidly and had a fatal outcome, despite “triple therapy” for RP-ILD. This case illustrates that patients with coexisting anti-MDA5⁺DM and MCTD have the former's typical clinical manifestations, and may develop ILD quickly rather than slowly as in MCTD, especially with the coexistence of anti-Ro52 antibodies.