Morphological Retrospective Study of Peritoneal Biopsies from Patients with Encapsulating Peritoneal Sclerosis: Underestimated Role of Adipocytes as New Fibroblasts Lineage?

Figure 3

Peritoneal biopsy representative photomicrographs of mesothelial phenotype markers expression: podoplanin (a–d), cytokeratin AE1/AE3 (e–h), and calretinin (i–l). Positive control of immunostainings for used antibodies (internal controls) (a, e, and i), control case: normal peritoneum (b, f, and j), case of acute peritonitis (control 3, c, g, and k), and case  1 of encapsulating peritoneal sclerosis (EPS) (d, h, and l). Physiologic expression of podoplanin (cytoplasm of endothelium in lymphatics (↠)), AE1/AE3 cytoplasm in epithelial cells of stomach and calretinin (cytoplasm in epithelial cells) (a, e, and i, resp.). (b, f, and j) Intact peritoneal membrane biopsy in controls; mesothelial cells (→) with obvious expression of adipocytes (#). (c, g, and k) Acute peritonitis case: hyperplasia of mesothelial cells. Superficial black lining related to the surgery technique (use of Indian ink). (d, h, and l) EPS case: loss of mesothelial cells (arrowheads) as attested by absence of podoplanin, AE1/AE3, and calretinin expressions. Note hyperplasia of mesothelial cells expressed all mesothelial markers podoplanin, cytokeratin AE1/AE3, and calretinin located in interstitial areas. The architecture of interstitium is strongly modified and contains several calretinin+ fusiform (fibroblasts-like) cells (arrow). Immunoperoxidase staining counterstained with haematoxylin. Original magnification: (a–l) ×20.