title: Malignant transformation in non-recurrent peritoneal cystic mesothelioma Our experience and review of the literature.
abstract: OBJECTIVE
  Cystic peritoneal mesothelioma is commonly regarded as a benign neoplasm at its first manifestation. It can only seldom show malignant transformation, and only after repeated postoperative recurrences.
  
  
  METHODS
  We hereby represent a unique case of peritoneal cystic mesothelioma, malignant since its first presentation. We observed a 73 year-old man presenting with intermittent abdominal pain and periumbilical swelling. At surgery, we found an extensive, oval-shaped, multi-lobed cystic formation that was surgically removed.
  
  
  RESULTS
  Histopathology was consistent with a malignant peritoneal cystic mesothelioma. In agreement with oncologists, we decided not to give any further therapy because of the few possibilities offered by systemic chemotherapy and the paucity of published data from the literature. We planned periodical follow-up including US scan every six and CTscan every 12 months.
  
  
  CONCLUSIONS
  Several cases of malignant transformation occurring after repeated recurrences of peritoneal mesothelioma have been reported. To our knowledge, this is the first case showing "ab initio" histological features of malignancy, typical of an active, proliferating and infiltrating lesion. In addition, advanced age and male gender of our patient are extremely peculiar
  
  
  CONCLUSIONS
  Our observation suggests the possibility, although very rare, that peritoneal cystic mesothelioma may present as malignant since its first manifestation.
  
  
  BACKGROUND
  Peritoneal cystic mesothelioma.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Santangelo
authors.forename: Marina
authors.initials: M
authors.lastname: Accardo
authors.forename: Ferdinando
authors.initials: F
authors.lastname: De Vita
authors.forename: Santolo
authors.initials: S
authors.lastname: Del Giudice
authors.forename: Federica
authors.initials: F
authors.lastname: Gallucci
authors.forename: Alessio
authors.initials: A
authors.lastname: Fabozzi
authors.forename: Massimo
authors.initials: M
authors.lastname: De Falco
mesh_terms: D000368:Aged; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology; D008297:Male; D008654:Mesothelioma / Q000473:pathology; D018261:Mesothelioma, Cystic / Q000473:pathology*; D000086002:Mesothelioma, Malignant; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D010534:Peritoneal Neoplasms / Q000473:pathology*; D011379:Prognosis; D018570:Risk Assessment; D012307:Risk Factors