Perplexing Malignant Peritoneal Mesothelioma in a Young Woman Without Exposure

Abstract

Introduction: Malignant mesothelioma is a rare disease that most often occurs in the pleura as a result of environmental exposure. Malignant peritoneal mesothelioma (MPM) is an even less common disease, accounting for approximately 10-15% of all cases of mesothelioma. Interestingly, MPM occurs more often in females than pleural mesotheliomas do for reasons that are not entirely understood. This higher proportion of females is thought to reflect their higher incidence of non-asbestos related disease. We report the case of a young woman with no known environmental exposure history who was diagnosed with MPM. Case Report: A healthy 20-year-old woman presented with dehydration and malnutrition. She reported a 2 month history of nausea, vomiting, diarrhea and abdominal pain. She also endorsed anorexia and an associated 20-30 pound weight loss over the same period. She had presented to her local emergency department 3 times with these complaints and had been found to have small pockets of ascites as well as hepatic sinusoidal dilatation on ultrasound. Additional workup including CT imaging, liver biopsy, paracentesis, colonoscopy and upper endoscopy had failed to identify any pathology. An MRI showed extensive soft tissue implants and omental caking in the abdomen and pelvis with abnormal peritoneal thickening and enhancement. The patient underwent a CT-guided biopsy of the omental soft tissue, which demonstrated a mesothelioma of epithelioid type. She was treated with peritonectomy, omentectomy, small bowel resection, total abdominal hysterectomy and installation and circulation of hyperthermic intraperitoneal chemotherapy. Biopsies of all sampled tissue showed extensive involvement by MPM. Of note, extensive imaging and evaluation did not capture any pleural involvement. Discussion: MPM is an exceedingly rare disease. Although previous studies have demonstrated an association between MPM and asbestos exposure in men, the same association has not been deduced in female populations. Other contributing exposures that have been described include radiation, chronic peritonitis, mica exposure and the simian virus-40. Both this patient's young age and lack of any such exposures reinforce the prevailing current wisdom that the risk factors for this rare, yet highly deadly disease have yet to be properly defined.Figure: A) Coronal MRI revealing broad sheet of omental caking along the left abdomen extending into the pelvis and diffuse peritoneal thickening and enhancement both along the abdominal wall and the bowel surfaces. Overall findings are suspicious for peritoneal malignancy. B) Coronal MRI revealing overall reduction in diffuse peritoneal disease burden with resolution of omental caking after therapy.