Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06126 (CD1a)
 2,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe 18 cases of a distinctive morphologic variant of primary thymic epithelial neoplasm characterized by a micronodular growth pattern associated with florid lymphoid follicular hyperplasia of the stroma. The tumors occurred in seven women and 11 men aged 41 to 76 years (mean, 58 years). All cases were asymptomatic and discovered incidentally on routine chest radiograph or during coronary artery bypass surgery. The tumors measured from 3 to 10 cm in greatest dimension and were well circumscribed and encapsulated. In seven cases, the lesions were grossly described as cystic or partially cystic masses. Histologically, they were characterized by a proliferation of small tumor nodules separated by abundant lymphoid stroma with prominent germinal centers. The nodules were composed of spindle cells containing oval nuclei devoid of atypia or mitotic activity. Immunohistochemical studies showed strong positivity of the spindle tumor cells for CAM 5.2 and broad spectrum keratin antibodies. The surrounding lymphoid cell population was strongly positive for LCA and L26 and showed a polyclonal pattern of staining for kappa and lambda. Stains for UCHL-1, CD1a, CD3, CD5, and CD99 were negative in the stromal lymphoid cell population. The tumor in one of the patients was associated with active pulmonary tuberculosis, and in another with anemia and splenomegaly of unknown etiology. None of the patients had clinical signs or history of myasthenia gravis or other autoimmune disorders. The present cases are interpreted as an unusual morphologic variant of spindle cell thymoma with prominent B-cell lymphoid hyperplasia. The possible significance of this phenomenon is discussed.
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PMID:Micronodular thymoma with lymphoid B-cell hyperplasia: clinicopathologic and immunohistochemical study of eighteen cases of a distinctive morphologic variant of thymic epithelial neoplasm. 1043 66

The perivascular space (PVS) of human thymus increases in volume during aging as thymopoiesis declines. Understanding the composition of the PVS is therefore vital to understanding mechanisms of thymic atrophy. We have analyzed 87 normal and 31 myasthenia gravis (MG) thymus tissues from patients ranging in age from newborn to 78 years, using immunohistologic and molecular assays. We confirmed that although thymic epithelial space (TES) volume decreases progressively with age, thymopoiesis with active T-cell receptor gene rearrangement continued normally within the TES into late life. Hematopoietic cells present in the adult PVS include T cells, B cells, and monocytes. Eosinophils are prominent in PVS of infants 2 years of age or younger. In the normal adult and the MG thymus, the PVS includes mature single-positive (CD1a(-) and CD4(+) or CD8(+)) T lymphocytes that express CD45RO, and contains clusters of T cells expressing the TIA-1 cytotoxic granule antigen, suggesting a peripheral origin. PBMCs bind in vitro to MECA-79(+) high endothelial venules present in the PVS, suggesting a mechanism for the recruitment of peripheral cells to thymic PVS. Therefore, in both normal subjects and MG patients, thymic PVS may be a compartment of the peripheral immune system that is not directly involved in thymopoiesis.
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PMID:Analysis of the human thymic perivascular space during aging. 1052 41

Thymomas with the characteristic pattern of small epithelial nodules separated by an abundant lymphoid tissue have been recently described with divergent interpretations. These thymomas are not specified in currently used classification systems. We present six such thymomas, including three that represented 1.38% of a series of 217 consecutive cases. These thymomas were totally encapsulated (Masaoka stage I, n=1) or minimally invasive (stage II, n=5). The epithelial cells of the nodules were oval and bland-appearing. In one case, these cells formed rosettes. Cysts, that were present in four cases, showed a strong linear expression of EMA and were associated with foci of glandular differentiation. The lymphoid tissue was composed of large immature (CD1a and CD99-positive) T-cell areas (with epithelial cells restricted to small foci of residual thymus) and of B-cell (CD20-positive) areas with germinal centers. Mature T-cells were also present. Furthermore, one case, associated with myasthenia gravis, had an important WHO type B2 (cortical) component. Such a combined case has not been previously reported. Our study demonstrates that so-called micronodular thymomas are rare, usually have clinical and pathological features of WHO type A (medullary) thymomas, and that the lymphoid component is hyperplastic corresponding to both immature T-cell lymphoid tissue and B-cell lymphoid hyperplasia with germinal centers.
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PMID:[Thymoma with epithelial micronodules and lymphoid hyperplasia: six cases of a rare and equivocal subtype]. 1241 Jan

Langerhans cell histiocytosis (LCH) is a neoplastic proliferation of Langerhans cells that occurs in a range of nodal and extranodal sites. Scattered reports of LCH within the thymus exist, typically among children within the setting of multifocal, multisystem disease. Rare cases of isolated LCH involving the thymus have occurred in adult patients with myasthenia gravis. We report a case of unifocal LCH involving the thymus in a middle-aged woman with a history of a resected leiomyosarcoma but no evidence of myasthenia gravis. Computed tomographic scans revealed an anterior mediastinal mass, which was excised and measured 9.0 cm. Histologic and immunophenotypic findings (CD1a, S100, and Fascin positive and CD68 negative) were consistent with LCH. To our knowledge, this is the first example of LCH occurring in a patient with a history of soft tissue sarcoma and one of the rare reported examples of LCH presenting as a large isolated lesion in the thymus of a nonmyasthenic adult.
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PMID:Langerhans cell histiocytosis involving the thymus. A case report and review of the literature. 1282 60

We report a case of type-B3 thymoma manifesting neuroendocrine differentiation. The patient was a 42-year-old woman who complained of shoulder pain but had no symptoms of myasthenia gravis or anemia. The tumor was located in the anterior mediastinum and had directly invaded the pericardium and left lung. Histological examination revealed that the tumor was lobulated by bands of fibrous tissue, perivascular spaces were scattered throughout the tumor, and there were a few intraepithelial lymphocytes. The vast majority of lymphocytes in the perivascular spaces and in the lobulated tumor were immunohistochemically positive for TdT, MIC2, and CD1a. The majority of tumor cells were polygonal and medium or large in size. The tumor cells were weakly positive for synaptophysin, chromogranin A, CD56, and NSE. Small nests of small, relatively uniform polygonal cells were observed facing the fibrous bands. These cells resembled the cells of carcinoid tumors and were strongly positive for NSE, synaptophysin, chromogranin A, and CD56. Ultrastructurally, sparse dense-core granules were observed in the cytoplasm of a few tumor cells. This is a unique case of thymoma with neuroendocrine differentiation, and to the best of our knowledge this is the first such case ever reported.
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PMID:Atypical thymoma (WHO B3) with neuroendocrine differentiation: report of a case. 1667 17

Follicular dendritic cell sarcoma is characterized by proliferation of spindled to ovoid cells reminiscent of follicular dendritic cells. However, the association of follicular dendritic cell sarcoma with a dense infiltration of immature T cells has not hitherto been reported. We report an unusual case of follicular dendritic cell sarcoma of the mesentery with immature T-cell proliferation in a 68-year-old man. The infiltrating immature T cells demonstrated expression of CD3, CD1a, TdT, and coexpression of CD4 and CD8 by immunohistochemistry. In addition, the patient was subsequently diagnosed with myasthenia gravis and paraneoplastic pemphigus and died of distant metastasis within 2 years after initial diagnosis of follicular dendritic cell sarcoma. The aggressive clinical course of this case contrasts with the indolent course of follicular dendritic cell sarcomas, and thus, the prognostic implications of follicular dendritic cell sarcoma with immature T-cell proliferation require clarification. The complication of myasthenia gravis and paraneoplastic pemphigus may suggest that immature T-cell proliferation has an autoimmunity-related systemic influence.
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PMID:Follicular dendritic cell sarcoma with immature T-cell proliferation. 1974 May 17

Nonclonal expansions of immature T cells outside of the thymus, termed indolent T-lymphoblastic proliferation (iT-LBP), have been identified in rare lymphoproliferative disorders. We report that iT-LBP is a frequent finding in cases of follicular dendritic cell sarcoma (FDCS), and shows an association with paraneoplastic autoimmune multiorgan syndrome (PAMS). We studied 31 cases of FDCS by paraffin immunohistochemistry using antibodies to CD21, CD23, CD35, clusterin, CXCL13, podoplanin, CD3, CD4, CD8, CD20, CD1a, and TdT. Chart review was performed to characterize the clinical behavior including evidence of autoimmune disease. FDCS occurred in a wide variety of nodal and extranodal sites. Fourteen of 31 (45%) cases contained immature TdT-positive T cells; in 5 cases these cells were numerous and present throughout the tumor. Four of these 5 patients with numerous immature T cells developed autoimmune disease, clinically categorized as PAMS and/or myasthenia gravis. PAMS persisted after tumor resection, causing severe morbidity and mortality. These findings suggest that the neoplastic follicular dendritic cells can recruit or foster the proliferation of immature T cells and that these cells may play a role in mediating PAMS. Recognition of iT-LBP in FDCS is important to avoid misdiagnosis as thymoma or T-lymphoblastic lymphoma, and may predict serious autoimmune complications in some patients.
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PMID:Follicular Dendritic Cell Sarcoma With Indolent T-Lymphoblastic Proliferation Is Associated With Paraneoplastic Autoimmune Multiorgan Syndrome. 3022 3