Basement membrane components as differential markers for mesenchymal tumors of various origin

We immunohistochemically analyzed the presence or absence of a pericellular basement membrane in benign and malignant soft tissue tumors of different origin--of peripheral nerve, smooth and striated muscle, fat tissue, connective tissue, blood and lymph vessels, cartilage and bone--to test the role of the expression of the BM components collagen IV, laminin, heparan sulfate proteoglycan (HSPG) and fibronectin as a differential diagnostic aid. All benign tumors revealed a BM feature corresponding to that of the normal tissue. Well differentiated sarcomas similarly showed a BM pattern close to that of the respective normal mesenchymal cells, so that these sarcomas were attributable to different histogenetic entities. Low differentiated sarcomas preserved in some, but not all, instances a typical BM pattern as well. Since the BM expression in most sarcomas of lesser degree of differentiation shows a distinctive BM pattern, we believe that the BM analysis of soft tissue sarcomas may be useful to establish a proper histogenetic classification of mesenchymal tumors.