Fig. 1

Histological findings of an NFM in a representative EPS patient. An NFM is a fibrous membrane-like structure attached to the surface of the visceral peritoneum proper (PM). a The NFM is located on the visceral peritoneal membrane and has the histological appearance of simple peritoneal sclerosis with severe fibrosis and obstructive vasculopathy (Masson stain, ×100, and bar = 200 μm). b The NFM is characterized by surface fibrin deposition and an interlacing of homogenous fibrous bundles with fibroblast-like cells (Masson stain, ×200, and bar = 100 μm). c Fibrin is deposited on the surface of the NFM and confirmed by immunohistochemical fibrin staining (IHC for fibrin, ×200, and bar = 100 μm). d Podoplanin is strongly positive on the cell membranes of intercalating fibroblast-like cells in the NFM (IHC for podoplanin, ×200, and bar = 100 μm)