Exuberant mesothelial proliferation mimicking malignant mesothelioma in a patient with prolonged VP shunt: A case report

Background: Ventriculo-peritoneal shunt (VP shunt) surgery is the most widely used procedure in the treatment of hydrocephalus. Common complications post-VP shunt insertion are infection, mechanical failure, as well as functional complications such as overor underdrainage. Rarely, abdominal complications can present remotely after the time of VP shunt insertion. We found no reportsin the literature describing peritoneal exuberant mesothelial hyperplasia mimicking mesothelioma, clinically, radiologically, andpathologically in a setting of VP shunt.Case: A 22-year-old female with a history of T cell lymphoma in 2002, suffered from CNS recurrence and increased intracranialpressure (ICP) in 2004 necessitating a VP shunt insertion. In 2015, she presented with abdominal pain. CT scan of the abdomenshowed omental nodular lesions that were biopsied and read first by a private pathology center as atypical mesothelial proliferationfavoring malignant mesothelioma. However, after reviewing the full medical history and evaluating additional surgical materialfrom the patient, review of the pathology specimen at the American University of Beirut concluded that the final diagnosis isatypical mesothelial proliferation favoring exuberant mesothelial hyperplasia possibly as a reaction to the long-standing VPshunt.Conclusion: It is often difficult for the pathologist to differentiate a malignant from a reactive mesothelial hyperplasia especiallyon biopsies or limited material due to sampling issues. Many features of reactive mesothelial hyperplasia can mimic malignantmesothelioma. This complication took place in the setting of a VP shunt.