SMALL BOWEL OBSTRUCTION SECONDARY TO ENDOMETRIOSIS

A 42-year-old woman is admitted to the hospital with abdominal pain, vomiting, asthenia and fever. Symptoms had started 10 days ago and had worsened in the last 24 hours. She refers to similar episodes in the past two years. On physical examination, there was a pain in the hypogastrium.

First, a contrast-enhanced computed tomography (CT) was performed (Fig. 1) where we identify small bowel obstruction, caused by a soft-tissue mass with moderate enhancement located in the right iliac fossa. The appendix was identified contiguous to the soft-tissue mass and it was not inflamed. The terminal ileum showed no signs of inflammation. To characterise the mass, a pelvic magnetic resonance (MR) was performed. The obstruction due to an ileal irregular soft-tissue lesion persisted. On T2-weighted images (Fig. 2 and 3) the soft-tissue mass was hypointense to muscle with scattered hyperintense foci, which is suggestive of endometrial tissue with scattered endometrial glands. On fat-saturated T1-weighted images (Fig. 4) the lesion was isointense and showed some very attenuated hyperintense foci representing haemorrhagic blood products. The rest of the pelvis showed no signs of endometriosis, which is very rare in cases of gastrointestinal endometriosis.

Endometriosis is a chronic disease causing a significant impact on a patient’s quality of life. It is characterised by the presence of endometrial tissue outside of the uterus. It affects 4-17% of menstruating women of which 37% present gastrointestinal tract involvement [1,2]. The most common gastrointestinal site is the rectosigmoid colon (70%), followed in order by the ileum, the appendix and the caecum [3]. Exclusive ileal involvement is rare (1-7%) [4]. Deep infiltrating endometriosis (DIE) is a severe form of endometriosis defined as subperitoneal endometrial implants larger than 5 mm in depth. Small bowel endometriosis is often asymptomatic. When symptoms present, they are nonspecific such as deep pelvic pain, constipation, diarrhoea, nausea, vomiting, abdominal bloating or haematochezia if the underlying endometrial tissue causes the mucosa to tear [1]. The endometrial implant infiltrating the bowel wall is subject to cyclical haemorrhage and leaking of endometriotic contents leading to chronic inflammation, fibrosis and stricture formation [5]. Bowel obstruction is reported in around 7 to 23% of cases of intestinal endometriosis [4]. In the gastrointestinal tract, DIE affects the mesenteric side of the serosa [1]. On contrast-enhanced CT imaging, DIE appears as a soft-tissue mass with mild to moderate enhancement. It can simulate an inflammatory process such as diverticulitis or appendicitis, or a neoplasm. In our case, the depiction of a normal appendix was essential to rule out complicated appendicitis and the location and absence of diverticula excluded diverticulitis. MRI is the modality of choice when DIE is suspected. It will present as an irregular, infiltrating, soft- tissue lesion characteristically iso- or hypointense on T2-weighted images, often associated with small cystic areas from endometrial glands [5]. On T1-weighted images, intestinal endometriosis is isointense to the muscle and may show scattered hyperintense foci on fat-saturated images due to haemorrhagic blood products. Usually, the mass also shows nonspecific restricted diffusion with low-apparent diffusion coefficient [6]. Bowel loops can show abnormal angulation towards the lesion. Depending on the degree of infiltration it can cause luminal narrowing or even bowel obstruction, as in our case. MRI findings of DIE were present in our case; therefore, the diagnosis of an endometrial ileal implant was done before the surgery. Our patient underwent an ileocaecal resection including the endometrial implant and she had a full recovery without any complication. Gastrointestinal endometriosis should be considered in the differential diagnosis of gastrointestinal disorders in menstruating women to provide optimal treatment. Written informed patient consent for publication has been obtained.