title: Bowel perforation as a presenting feature of pheochromocytoma: case report and literature review.
abstract: OBJECTIVE
  To report a case of colonic perforation as the initial manifestation of pheochromocytoma and discuss the underlying pathophysiologic mechanism.
  
  
  METHODS
  The clinical, biochemical, radiologic, and pathologic findings are described. In addition, the management of the patient is discussed and the relevant literature reviewed.
  
  
  RESULTS
  A 57-year-old man presented with large bowel perforation after pseudo-obstruction. Emergency laparotomy revealed two cecal perforations but no obstructing lesion; however, hypertension persisting postoperatively raised the suspicion of pheochromocytoma. This diagnosis was confirmed by measurement of 24-hour urinary hydroxymethylmandelic acid excretion and computed tomography of the abdomen. The tumor was subsequently resected without complication or recurrence of bowel symptoms. The pathophysiology of bowel perforation in patients with pheochromocytoma is not entirely clear but most likely involves bowel ischemia and necrosis as a result of mesenteric vasoconstriction. This setting coupled with increased intraluminal pressure as a consequence of pseudo-obstruction may cause perforation.
  
  
  CONCLUSIONS
  Bowel perforation in patients with pheochromocytoma is rare and thought to be a consequence of intestinal ischemia and altered motility. This is potentially a life-threatening complication, particularly if the tumor remains undiagnosed and an emergency surgical procedure is necessary. Pharmacologic treatment of pheochromocytoma during pseudo-obstruction may prevent subsequent perforation. Clinicians should be aware of the potential gastrointestinal presentation of this tumor.
authors.affiliation: Department of General Surgery, Norfolk and Norwich University Hospital, Norwich, Norfolk, United Kingdom.
authors.forename: Vasu
authors.initials: V
authors.lastname: Karri
authors.forename: Sumaira Latif
authors.initials: SL
authors.lastname: Khan
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Wilson
mesh_terms: D000005:Abdomen / Q000000981:diagnostic imaging; D000310:Adrenal Gland Neoplasms / Q000150:complications / Q000175:diagnosis*; D000311:Adrenal Glands / Q000473:pathology / Q000601:surgery; D005767:Gastrointestinal Diseases / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D007416:Intestinal Perforation / Q000175:diagnosis* / Q000209:etiology; D007422:Intestines / Q000473:pathology / Q000601:surgery; D007668:Kidney / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010673:Pheochromocytoma / Q000150:complications / Q000175:diagnosis* / Q000601:surgery; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography