Thymomas: a cytological and immunohistochemical study, with emphasis on lymphoid and neuroendocrine markers

<p>Abstract</p> <p>Background</p> <p>The current study correlates cytologic morphology with histologic type and describes immunophenotypes with a focus on epithelial, neuroendocrine, and lymphoid characteristics in an institutional series of surgically excised thymomas.</p> <p>Methods</p> <p>Fine needle aspirates (FNAs) and surgical specimens were retrospectively analyzed, and immunohistochemical stains were performed for EMA, cytokeratin 7, cytokeratin 20, CD57 CD5, bcl-2, calretinin, vimentin, CD3, CD20, CD1a, CD99 and Ki67. Tumors were classified by WHO criteria.</p> <p>Results</p> <p>There were eleven male and six female patients with an age range of 41 to 84 years (mean, 61 years) and a male to female ratio of 1.8:1. Four thymomas (4/17, 23.5%) were associated with neuromuscular disease: myasthenia gravis (n = 3) and limbic encephalitis (n = 1). FNA, under CT guidance, was performed in 7 cases. The positive predictive value for thymoma by FNA cytology was 100% and the sensitivity was 71%. Thymomas associated with neuromuscular disorders were WHO types B2 (n = 1) and B3 (n = 3), and showed a strong expression of CD57 in the majority of neoplastic epithelial cells accompanied by large numbers of CD20+ intratumoral B lymphocytes. Two of seventeen (11.7%) thymomas (all sporadic B3 type) contained numerous neoplastic epithelial cells positive for CD5 and bcl-2.</p> <p>Conclusion</p> <p>Our results suggest that thymomas associated with autoimmune disorders contain a significant population of CD20+ intratumoral B lymphocytes. Strong CD57 positivity in thymomas may suggest a concomitant neuromuscular disorder, notably myasthenia gravis. CD5 expression is of limited value in the differential diagnosis of primary thymic epithelial neoplasms since both thymic carcinomas and thymomas may express CD5.</p

Fatal parvoviral myocarditis: A case report and review of literature

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Terahertz photoconductivity and plasmon modes in double-quantum-well field-effect transistors

Double-quantum-well field-effect transistors with a grating gate exhibit a sharply resonant, voltage tuned terahertz photoconductivity. The voltage tuned resonance is determined by the plasma oscillations of the composite structure. The resonant photoconductivity requires a double-quantum well but the mechanism whereby plasma oscillations produce changes in device conductance is not understood. The phenomenon is potentially important for fast, tunable terahertz detectors

942-41 Dysplasia of the Atrioventricular Nodal Artery in Patients with Mitral Valve Prolapse and Sudden Cardiac Death

Patients with isolated mitral valve prolapse (MVP) without significant mitral regurgitation are at a slightly increased risk of sudden cardiac death compared to the normal population. The mechanism(s) of sudden cardiac death in isolated MVP are uncertain. We studied gross hearts and histologic sections of the atrioventricular (AV) node in 21 patients with isolated MVP dying suddenly without apparent cause other than MVP (Group 1, mean age 36±8 years, mean heart weight 420±89 grams). No patient in Group 1 had a history of or treatment for mitral regurgitation, and no left atrial dilatation was present at autopsy. Sudden cardiac death MVP cases were compared to 15 control hearts from trauma victims without cardiac disease (Group 2, mean age 30±7 years, mean heart weight 350±96 grams). Sections of the artery to the AV node within the atrial septum (mean 7 levels in each group) were stained for elastic tissue and proteoglycans. Dysplasia was defined as focal deposition of proteoglycans within the media and partial disruption of the internal elastic lamina. The ratio of lumen area to arterial area was determined by computerized planimetry at the level of greatest luminal narrowing and measured (mean±SEM) 0.33±0.04 for Group 1 and 0.52±0.04 for Group 2 (p=0.001) this ratio was independent of heart weight, age, or sex of patient by stepwise regression. Dysplasia of the AV nodal artery was present in 9/21 (43%) hearts in Group 1 versus 1/15 (7%) hearts in group 2 (p&lt;0.02) We conclude that narrowing of the AV nodal artery and arterial dysplasia are more prevalent in patients with MVP and sudden cardiac death than controls and may represent a more generalized disorder of proteoglycan deposition. The relationship between these findings and sudden cardiac death needs to be further studied