Expression of podoplanin and calretinin in meningioma: an immunohistochemical study

Abstract

Meningioma is derived from arachnoid cells covering the surface of the brain and spinal cord, and it has characteristics shared by mesothelioma arising from the pleura and peritoneum in that it takes an epithelioid appearance despite its mesenchymal origin. We examined the immunohistochemical expression of podoplanin and calretinin, both of which are well-known markers of mesothelioma, in 24 surgical cases of meningioma of various types. In most cases, a linear immunoreactivity for podoplanin was found along the cell surface of most neoplastic cells. An intracytoplasmic, finely granular, or diffuse immunoreactivity was also noted in some cells. These findings corresponded well to immunoreactivity for epithelial membrane antigen (EMA), but immunoreactivity for podoplanin was more crisp or sharply delineated and clear compared with that for EMA. These findings indicate that podoplanin can be used as an immunohistochemical marker that is equivalent to EMA in the differential diagnosis of meningioma. However, most meningiomas did not contain calretinin-immunoreactive cells, a finding that differs from the diffuse immunoreactivity seen in mesothelioma.

Expression of Mesothelioma-Related Markers in Meningiomas: An Immunohistochemical Study

“…A total score for each case was calculated by adding the two aforementioned scores. In addition, the staining pattern (cytoplasmic +/or membranous) was recorded [2]. …”

“…Recent studies have proposed that meningiomas share common histogenetic and phenotypic characteristics with mesotheliomas [2]. …”

“…Despite their controversial embryogenesis, arachnoid cells differentiate to form a thin membranous structure covering the surfaces of the brain and spinal cord. In this regard, they resemble mesothelial cells that cover the surfaces of the pleural and peritoneal cavities [2]. …”

“…In addition, both tumors share, on the ultrastructural level, the presence of desmosomes and intermediate filaments [2, 5, 7]. …”

The Role of Podoplanin in the Biology of Differentiated Thyroid Cancers

“…PDPN is expressed in the lymphatic endothelial cells (LEC), but not in blood endothelial cells (BEC), and thus represents a specific marker of lymphatic endothelium and lymphangiogenesis [11]. Despite the specificity of its expression in lymphatic endothelium, PDPN has also been detected in various cancers [18], [19], [20]. The biological function of PDPN has not been fully defined, but the available data strongly suggest that it may play an important role as a mediator of tumor cell invasion [21].…”