Rhabdomyomatous carcinoma of the thymus

Myoid cells have been described in the thymus in association with a variety of benign and malignant conditions. The presence of a benign rhabdomyomatous component in a malignant primary thymic epithelial neoplasm, however, is extremely rare. A case of poorly differentiated carcinoma of the thymus arising in the posterior mediastinum containing a prominent rhabdomyomatous component is described. The patient, a 70-year-old woman, was seen for a large posterior mediastinal mass. An open chest biopsy revealed an extensively necrotic tumor composed of islands of atypical cells with vesicular nuclei and prominent nucleoli with numerous mitotic figures admixed with abortive glandular structures. Interspersed with the malignant epithelial components were islands of large cells containing brightly eosinophilic cytoplasm and small, round, excentrically placed nuclei. Immunohistochemical studies showed strong positivity of the epithelial cells for cytokeratin and strong positivity of the myoid cells for pan-actin, desmin, and myogenin. The possible relationship of the rhabdomyomatous component of this tumor with the myoid cells of the thymus is discussed.

Theoretical approach including friction for determining strain limits in punch stretching of anisotropic sheet metals

A new analytical theory including friction was developed to assess strain limits in punch stretching of anisotropic sheet metals. This new approach takes into consideration the anisotropic behaviour of sheet materials and could explain the mechanical behaviour of a variety of anisotropic sheet materials. The theory explains the sheet metal failure so for the drawing as the stretching region of the forming limit curve, particularly for materials that present the strain-ratio dependence of limit strain ε 1, where dε 1/dρ is not always greater than zero. dε 1/ dρ or dε 1/dε 2 could be equal to or smaller than zero for a range of materials. Therefore, this new theory can explains such experimental observations, besides to assuming that membrane element relations near the pole, for the case of punch stretching are dependent of sheet metal properties as the process history and also suggests that the onset of local necking is controlled by shear. Thus, theoretical results obtained through this new approach are compared with experimental results available in the literature. It is demonstrated the effect of friction on a FLC curve for both regions, drawing and stretching. © 2010 American Institute of Physics.