A unique case of gliomatosis peritonei in a man, following a retroperitoneal teratoma.

We present an unusual case of a 56-year-old man presenting with abdominal swelling. Imaging revealed a large abdominal 23 cm cystic mass, which radiologically appeared to be related to the small bowel. There was an attempted surgical removal by the general surgeons. It was histologically confirmed as a retroperitoneal cystic teratoma with immature neural elements with incomplete resection margins. Residual disease was found at re-imaging 3 months later and a further block dissection was performed, with histology confirming recurrence. Thirteen months later, imaging revealed recurrent disease with peritoneal involvement. At laparoscopic exploration, there was peritoneal seeding, and biopsies confirmed a diagnosis of gliomatosis peritonei, secondary to the retroperitoneal teratoma. The patient proceeded to have combination chemotherapy to achieve stable disease on imaging. A month after completion, sadly, the disease progressed; the patient received best supportive care. 2015 BMJ Publishing Group Ltd.