Sclerosing encapsulating peritonitis and methotrexate

A 36-year-old female presented with a 6-month history of intermittent obstructive small bowel symptoms and an associated weight loss of 19 kg. Her symptoms began 8 weeks after a short pulse course of methotrexate (each dose of 110 mg) for a molar pregnancy. Other past medical history included an excision of abdominal lipoma, Caesarean section and a fetal death in utero. Outpatient investigations, including ultrasound and gastroscopy, did not find any cause. With worsening symptoms, she was admitted to a hospital. Clinical findings were those of a non-distended abdomen associated with mild epigastric tenderness. Other than a CRP of 65, her blood investigations were unremarkable with a beta-HCG below 2. Abdominal Xray revealed small bowel dilation with multiple air-fluid levels and collapsed large bowel. Computerised tomography (CT) scan confirmed dilatation of the small bowel with distal collapse of the colon, compatible with a distal small bowel obstruction. A subsequent small bowel follow-through examination established dilated small bowel despite a transit time of only 3 hr. The patient was managed conservatively with an insertion of nasogastric tube analgesia and antiemetics. Her symptoms manifested on resumption of oral intake, and a surgical opinion was sought. She underwent a laparotomy and a 3-hr division of adhesions. The intraoperative findings were of severe peritoneal fibrosis and ‘cocooning’ of the small bowel. The last metre of ileum was found to be compacted into a 10-cm fibrous ‘ball’. She spent a further 10 days in hospital with an uncomplicated recovery and resolution of symptoms. Samples of the peritoneal adhesions were sent for histology and showed features of sclerosing inflammatory peritonitis. Histological sections demonstrated dense fibrous connective tissue, within which bands of amianthoid collagen fibres, admixed with chronic inflammatory cells and reactive fibroblasts. Discussion