title: Is pneumatosis cystoides intestinalis gas-distended and ruptured lymphatics? Reappraisal by immunohistochemistry.
abstract: BACKGROUND
  Pneumatosis cystoides intestinalis (PCI) is a condition with multiple gas-filled cysts within the bowel wall, associated with diverse background diseases. Its pathogenesis is still a mystery. Some previous observations scattered in the literature have suggested an association of the cystic spaces in PCI with the lymphatics.
  
  
  OBJECTIVE
  To further investigate whether PCI results from the ballooning of gas-filled lymphatic channels.
  
  
  METHODS
  We did immunostaining of podoplanin, a mucoprotein preferentially expressed in lymphatic endothelial cells, in 13 cases (8 men, 5 women; age range, 18-80 years) of PCI. Ten cases were diagnosed in resected segments of bowel and 3 in biopsies. Pneumatosis was seen in the right side of the colon (9 cases), transverse colon (1 case), sigmoid colon (1 case), and small bowel (2 cases). In addition, immunostaining for CD31, calretinin, WT1, CD68, smooth muscle actin, desmin, vimentin, and cytokeratins was also performed for comparison and correlation.
  
  
  RESULTS
  A strong immunopositivity of podoplanin was seen in a condensed linear structure in the pericystic interstitium in 100% of the cases, but was not seen in the overlying giant and flat cells that were all CD68-positive histiocytes. Meanwhile, the podoplanin-expressing structure was negative for calretinin and WT1, which ruled out the possible mesothelial origin. There were coexistent variable immunopositivity of smooth muscle actin, which suggests an admixture of myofibroblasts. These findings indicated that the PCI cases were gas-distended lymphatics with the lymphatic epithelium ruptured and embedded in the reactive histiocytes and giant cells.
  
  
  CONCLUSIONS
  Our findings support the lymphatic theory about the pathogenesis of PCI.
authors: From the Department of Pathology and Laboratory Medicine, University of Calgary, Calgary Laboratory Services, Calgary, Alberta, Canada (Drs Gui, Eidus, and Falck); the Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York (Dr Zhou); the Department of Pathology, McGill University, Montreal, Montreal, Quebec, Canada (Dr Gao); and the Department of Pathology, Weill Cornell Medical College, Cornell University, New York, New York (Dr Qin).
authors: Xianyong
authors: X
authors: Gui
authors: Yi
authors: Y
authors: Zhou
authors: Leslie
authors: L
authors: Eidus
authors: Vincent
authors: V
authors: Falck
authors: Zu-hua
authors: ZH
authors: Gao
authors: Lihui
authors: L
authors: Qin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D003106:Colon / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D004108:Dilatation, Pathologic; D004729:Endothelium, Lymphatic / Q000378:metabolism / Q000473:pathology*; D005110:Extracellular Space / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D007421:Intestine, Small / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D008206:Lymphatic Diseases / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D008208:Lymphatic System / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D008875:Middle Aged; D011006:Pneumatosis Cystoides Intestinalis / Q000473:pathology* / Q000601:surgery; D012189:Retrospective Studies; D055815:Young Adult; D000098853:Podoplanin
chemical_list: D015415:Biomarkers; D008562:Membrane Glycoproteins; C117468:PDPN protein, human; D000098853:Podoplanin