B0619 - Peritoneal Mesothelioma as an Unexpected Cause of Recurrent Abdominal Ascites

Nida Anwaar, MD¹, Jason Chang, MD², Muhammad Masood, MD^1
1Danbury Hospital, Danbury, CT; ²Stanford University Medical Center, Palo Alto, CA

Introduction: Peritoneal mesothelioma is an aggressive neoplasm that arises from the lining mesothelial cells of the peritoneum. The disease is very rare with an incidence of 1 case per 4–5 million of the population. Peritoneal mesothelioma accounts for approximately 20–30% of all mesothelioma type cancers, and as with all forms of mesothelioma, asbestos exposure is a strong risk factor associated with the disease.

Case Description/Methods: A 68-year-old male presented with progressively worsening abdominal distension and generalized lethargy for a few months. His past medical history includes untreated rheumatoid arthritis and a 40-pack-year history of tobacco smoking with recent cessation. He was a veteran in the army reserve but never saw combat. He had undergone therapeutic paracentesis removing 5 L of clear yellow fluid a week prior, but developed recurrence of abdominal distention within a few days thus came to the emergency room for evaluation. A CT scan of abdomen and pelvis with contrast revealed tense ascites throughout the abdomen, in addition to hepatic nodules and a large area of soft tissue attenuation suspicious for diffuse carcinomatosis. A diagnostic paracentesis performed in the ED was negative for malignant cells. He was admitted to the hospital for recurrent ascites requiring workups for possible malignancy. Soon after admission he underwent a large-volume paracentesis which removed 5.1 L of yellow, foamy fluid with no evidence of bacterial infection. A CT-guided biopsy of an omental mass revealed malignant mesothelioma, epithelioid type. Per assessment by Medical Oncology patient was determined to be a poor candidate for cytoreductive surgery (CRS) or HIPEC therapy, but palliative chemotherapy was considered a viable option. He was subsequently discharged from the hospital with a peritoneal drainage catheter to be used thrice-weekly for rapid re-accumulation of ascites.

Discussion: There is currently no consensus as to the optimal treatment for peritoneal mesothelioma. For patients who are not candidates for CRS/HIPEC, systemic chemotherapy with a pemetrexed-containing regimen is usually the preferred option. Immunotherapy has shown activity in pleural mesothelioma, but data is limited on its use in mesothelioma of extrapleural sites and there are no consensus-based guidelines regarding immunotherapy for peritoneal mesothelioma. In conclusion, peritoneal mesothelioma is a rare cancer with a poor prognosis, and further studies are needed to determine the best treatment option.


Disclosures:


Nida Anwaar, MD¹, Jason Chang, MD², Muhammad Masood, MD¹. B0619 - Peritoneal Mesothelioma as an Unexpected Cause of Recurrent Abdominal Ascites, ACG 2022 Annual Scientific Meeting Abstracts. Charlotte, NC: American College of Gastroenterology.