Plexiform Neurofibromas with Mast Cell Infiltration of the Gallbladder in a Patient with Cholelithiasis

This article describes an unusual case of plexiform neurofibromas incidentally found in the gallbladder resected for cholelithiasis and choledocholithiasis. S-100 protein is detected in the tumor cells. In addition, mast cell infiltration is observed within or/and around the neurofibromas demonstrated by toluidine blue and Giemsa's stains. To our knowledge, mast cell infiltration is found in many reported neurofibromas and has been hypothesized as a possible pathogenesis of these neoplasms. Based on results in this case, we believe that mast cells are also an important associated marker for the plexiform neurofibromas of gallbladder.