Rapid Progression of Malignant Peritoneal Mesothelioma Mimicking a Postoperative Complication in a Young Woman: A Case Report.

BACKGROUND Malignant peritoneal mesothelioma is a rare disease with a poor prognosis that often presents with vague symptoms and inconclusive laboratory test results. Causes include industrial pollutants, primarily asbestos, and certain genetic mutations, such as BAP1. Due to the nonspecific symptoms, it is often incidentally diagnosed during or after other surgical procedures. CASE REPORT A 35-year-old healthy woman underwent an uncomplicated laparoscopic left salpingo-oophorectomy for a symptomatic large ovarian mature cystic teratoma. She subsequently presented with late-onset postoperative fever, leukocytosis, and multiple intra-abdominal masses. Following an exploratory laparotomy, extensive infectious disease evaluation, and multiple biopsies requiring interdisciplinary collaboration, malignant peritoneal mesothelioma was diagnosed by positive histologic staining of an omental biopsy for D2-40 and CK5/6. This first specimen was positive for BAP1, with the second, a liver biopsy, testing negative for BAP1. The tumor cell testing was also notable for mutations in NF2, MLL2, and ARID1A, and the hereditary cancer genetic testing was overall unremarkable. Her disease progressed rapidly, and she died 6 months after her initial procedure. CONCLUSIONS This case of rapidly developing malignant peritoneal mesothelioma following surgical management of an ovarian mature teratoma highlights the complexity in diagnosing a rare disease that presents with nonspecific symptoms in an otherwise young and healthy woman. The rapid disease course was likely accelerated by expansive intraperitoneal spread and multiple somatic oncogenic mutations in BAP1, NF2, MLL2, and ARID1A. Gynecologists should keep a broad differential for postoperative complications, as occult malignancies can present with symptoms that mimic postoperative complications.