The thymic "myoidzellen" and myasthenia gravis

Velde, Robert L. Van de

doi:10.1001/jama.198.3.287

Cited by 21 publications

(14 citation statements)

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“…We interpreted these findings as suggesting that myoid cells are an intermediate state between epithelial cells and muscular cells. Although the neural crest [15], perithymic mesenchymal cells [23], transformed thymic epithelial cells [22], and thymic stromal elements of postcapillary venules [25] have also been suggested as possible origins of myoid cells, our immunohistochemical results seem to strongly support our thymic epithelial transformation theory [22]. Thymomatous epithelial cells have also been reported to share a common epitope with skeletal muscle [5], providing further support for our theory.…”

Section: Discussionsupporting

confidence: 83%

Two cases of ectopic hamartomatous thymoma

et al. 2000

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Ectopic hamartomatous thymoma (EHT) is a rare benign neoplasm. Since it was named by Rosai et al. in 1984, 24 cases have been reported. We herein report two cases of EHT, one of which presented with massive myoid cells, and review the literature related to EHT. Both of our cases displayed the typical features of EHT: (1) nests of epithelial cells, including solid, cystic, or glandular epithelial islands; (2) spindle cells dominating the microscopic picture; and (3) adipose cells which intermingle haphazardly to impart a hamartomatous quality to the tumor. In this paper, we observed massive myoid cells and the transition from spindle epithelial cell to myoid cell in one of our cases. Immunohistochemical examinations showed that the main component of EHT, spindle cells, was positive for cytokeratin and epithelial membrane antigen (EMA). Intriguingly, the myoid cells simultaneously expressed cytokeratin, EMA, myoglobin, and creatine kinase-mm, suggesting that myoid cells may originate from epithelial cells and are an intermediate state between epithelial cells and muscular cells.

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Section: Discussionsupporting

confidence: 83%

Two cases of ectopic hamartomatous thymoma

et al. 2000

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“…It has been suggested that the rare musclelike "myoid" cells found in the thymus might be involved in autosensitization 117, 19,36,37,41). Patients with MG, especially those with thymoma, frequently have autoantibodies to striational muscle antigens 13 51, in addition to the pathogenic anti-acetylcholine receptor (anti-AChR) antibodies that are responsible for their muscle weakness 11, 11, 13, 22, 33}.…”

mentioning

confidence: 99%

Acetylcholine receptors in human thymic myoid cells in situ: An immunohistological study

Schluep

Willcox

Vincent

et al. 1987

Annals of Neurology

209

113

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Myoid cells were studied by double immunofluorescence in sections of thymus from 47 patients with myasthenia gravis and 15 control subjects, using polyclonal sheep anti-troponin T and monoclonal antibodies to troponin I, striated muscle myosin, and acetylcholine receptor (AChR). The myoid cells were rare and located mainly in the medulla, and most were clearly positive for AChR; labeling was similar with four individual monoclonal antibodies specific for extrajunctional AChR and five that also recognize endplate AChR. They were mostly keratin-positive and consistently HLA-DR-negative. In the myasthenia gravis samples, the myoid cells were similar but largely confined to medullary epithelial areas; AChR labeling was slightly weaker, but otherwise they did not differ noticeably from those of control subjects. A preliminary finding was of even rarer AChR-positive/HLA-DR-positive antigen-presenting (possibly) cells seen in 9 of 9 myasthenia gravis samples and in none of 9 control samples. Although myoid-cell AChR appears antigenically similar to extrajunctional muscle AChR, and must therefore express the epitopes that myasthenics' antibodies recognize, these cells do not appear to be foci of immunological stimulation in myasthenia gravis.

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“…Na literatura, vários métodos são referidos para evidenciar as células mióides em timos humanos e de outras espécies: hematoxilina, hematoxilina e eosina, ácido periódico de Schiff (PAS), hematoxilina de ácido fosfotúngstico (PTAH), anticorpo antimioglobina e anticorpo antidesmina 8,10,14,16,[22][23][24] . Preferimos utilizar marcador imuno-histoquímico antidesmina com base nos relatos da literatura que demonstraram melhor identificação das células mióides em razão da grande quantidade de desmina existente nelas 11,13,14 .…”

Section: Idade Em Anos Número De Pacientes Média De Célulasunclassified

“…Estudos do mecanismo auto-imune da placa motora e sua relação com a patogênese da miastenia grave, serviram de base para os trabalhos que investigaram as células primordiais tímicas de humanos e animais [5][6][7][8] . As células mióides foram reconhecidas e sugeridas como prováveis elementos que reagiriam com anticorpos antimúsculo 9,10 .…”

Section: Introductionunclassified

Determinação imunohistoquímica da presença de células mióides em pacientes submetidos à timectomia

Ladipo

Carvalho

Rapoport

et al. 2004

Rev. Col. Bras. Cir.

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OBJETIVO: Detectar e quantificar células mióides em timos de pacientes com miastenia grave, estabelecendo possível correlação entre a quantidade de células mióides com variáveis demográficas e clínico-patológicas. MÉTODO: Foram analisados por meio de método imuno-histoquímico com anticorpo antidesmina (clone D33; marca Dako), timos de 22 pacientes (16 mulheres e seis homens, entre 12 e 61 anos) submetidos à timectomia, entre 1981 e 1995, no Serviço de Cirurgia Torácica do Hospital Heliópolis como parte do tratamento de miastenia grave. RESULTADOS: As maiores médias de células mióides foram encontrados em timos dos pacientes da raça negra (29,4:17,8), do sexo feminino (23,2:13,0) e com faixa etária entre 60 e 80 anos (média de 33,0). Pela classificação clínica da Fundação de Miastenia Grave da América (MGFA), a maior média de células mióides (26,7) encontra-se na classe IIIa, sendo do tipo histológico de hiperplasia verdadeira (média 42,0). As células mióides foram identificadas em 11 timos com hiperplasia linfóide, três hiperplasias verdadeiras e em quatro timos normais. Os timomas malignos (três) e um timo normal não apresentaram células mióides. CONCLUSÕES: As células mióides podem ser identificadas e quantificadas pelo método imuno-histoquímico com anticorpo antidesmina, porém não existe correlação entre a quantidade de células mióides e as variáveis demográficas, clínico-patológicas. Elas não foram identificadas no timoma fusocelular.

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The thymic "myoidzellen" and myasthenia gravis

Cited by 21 publications

References 0 publications

Two cases of ectopic hamartomatous thymoma

Two cases of ectopic hamartomatous thymoma

Acetylcholine receptors in human thymic myoid cells in situ: An immunohistological study

Determinação imunohistoquímica da presença de células mióides em pacientes submetidos à timectomia

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