Question: A 14-year-old girl of African descent, presented with severe abdominal pain at the pediatric department. The pain had started 3 days earlier and initially was intermittent, diffuse, and cramping. At presentation it had become continuous, progressively increasing in intensity, and accompanied by vomiting up to 3 times a day. She reported the tendency to move around constantly in search of a comfortable position. There was no fever, diarrhea, or dysuria and she regularly passed stool. Her medical history was unremarkable and she claimed not to be sexually active. On clinical examination, a sick-looking girl was noted with normal vital signs. Auscultation of heart and lungs revealed no abnormalities. A nondistended abdomen with reduced abdominal peristalsis was noted in addition to diffuse tenderness at the slightest touch, hampering deep palpation. No muscle guarding was noted, however. The intra-abdominal organs could not be palpated and there was no vaginal discharge. Her laboratory results showed hemoglobin of 8.6 g/dL, mean corpuscular volume of 67.3 fL, leukocytes of 10.2 Â 10 3 /mL, platelets of 394 Â 10 3 /mL, serum iron of 20 mg/dL, C-reactive protein of 32.2 mg/dL, serum creatinine of 0.76 mg/dL, and blood urea nitrogen of 20 mg/dL. In addition, normal coagulation times, glucose, electrolytes, and liver enzymes were noted. Her urinalysis showed microscopic leukocyturia and hematuria with mild proteinuria (0.39 g/L), raising suspicion of a urinary tract infection. Pregnancy testing was negative. An ultrasound of the abdomen was done and showed some free abdominal fluid, but the appendix could not be identified. Other abdominal organs including the kidneys and gallbladder did not show stones or other abnormalities. To exclude a surgical origin a computed tomography (CT) of the abdomen with oral contrast was performed. Computed tomography imaging (Figure A) revealed the presence of free abdominal fluid, but once again no appendix could be identified. There were also signs of small bowel obstruction with a positive small bowel feces sign. What is the diagnosis and what would your next step be? See the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI.