Human thymus development and thymoma behavior remain elusive, in spite of many acquisitions in the field in last decades. In the present paper, we analyzed the immunohistochemical expression of D2-40 in the normal human thymus and thymoma. In both fetal and postnatal normal thymus, we found a strong expression of D2-40 in the subcapsular and cortico-medullary epithelial cells, and lack of expression in the thymus of involution. These findings support a role for podoplanin in the proliferation of some subtypes of epithelial cells of the normal thymus stroma. In thymoma, the expression of D2-40 was detected in neoplastic cells in 18 from 26 cases (69.23%). No correlation was found between D2-40 expression and histological types of thymoma, but strong correlation was noticed with tumor stage. Based on these results, it is suggested that D2-40 expression is a good predictor of invasion and can be considered as a potential target for therapy in selected cases.
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A cytologic diagnosis of thymoma is extremely challenging. In part, this is because the tumor is uncommon and aspirates are infrequently encountered, a technically proficient interventional radiolo- gist is needed, epithelial cells may be difficult to recognize in lymphoid rich aspirate smears, and there is inherent sampling error in a tumor that frequently displays heterogeneous histopathology. Critical to the cytologic diagnosis of most WHO Type B thymomas is the recognition of a distinct population of epithelial cells mixed with lymphocytes.Read More →