ARRS 2022 Abstracts

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E1469. Pelvic Cognition: A Case Report and Imaging Overview of Gliomatosis Peritonei
Authors
  1. Robert Becker; Stanford Health Care
  2. Alexander Mazal; Stanford Health Care
  3. Luyao Shen; Stanford Health Care
Background
Gliomatosis peritonei (GP) is a rare disease, often associated with ovarian teratomas. It is characterized by low grade mature glial tissue implants within the omentum and peritoneum. The precise etiology of GP has not yet been determined. The leading hypothesis suggests that it may be caused by capsular defects of the primary teratoma with dissemination via angiolymphatic channels within the peritoneum. With increasing number of reports of GP, every radiologist should be familiar with this disease entity. Formal guidelines for imaging follow-up need to be established.

Educational Goals / Teaching Points
Imaging cannot accurately distinguish GP from peritoneal carcinomatosis; however, it may be suggested in the presence or history of a teratoma. Due to the risk of recurrence and the potential for malignant transformation, long-term imaging follow-up is necessary, although no formal guidelines have been established.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Imaging characteristics of GP are similar to those of peritoneal carcinomatosis, ranging from non-visualization to large peritoneal masses. Imaging evaluation generally demonstrates thickening and nodularity along the peritoneal reflections and omentum with associated mesenteric fat stranding. Ascites may also be present. Nodular implants are of intermediate echogenicity and are hypoechoic compared to the peritoneum. Infiltration of the omentum and mesentery will result in hyper-echogenicity. Contrast imaging may improve sensitivity of detection, with nodularity demonstrating slow, progressive enhancement. Deposits of glial tissue demonstrate intermediate T2 signal and progressive enhancement on delayed phase acquisition. In contrast to peritoneal carcinomatosis, surgical resection of glial implants may be curative; however, extensive disease burden often precludes complete surgical resection so conservative approach is pursued. Furthermore, tumors often recur, and cases of malignant transformation have been described. In such cases, salvage chemotherapy may be recommended. Clinical follow-up of GP with tumor markers provides false reassurance as these markers may remain within normal limits. Imaging therefore plays a crucial role in follow-up for monitoring of tumor recurrence or malignant transformation; however, there are currently no established guidelines on the modality, frequency, or duration of imaging follow-up.

Conclusion
GP is a rare disease entity that every radiologist should be familiar with. Though imaging cannot accurately distinguish GP from peritoneal carcinomatosis, in the appropriate clinical context, the radiologist may be able to suggest this low-grade pathology. As more cases continue to present, further education and research on GP are necessary. This educational exhibit will present a case report of GP by MRI and CT with subsequent recurrence after surgical resection with review of theorized etiology, pathologic diagnosis, recommended treatments, and request for establishment of formal guidelines for imaging follow-up.