Intermesenteric Appendicular Abscess, a Diagnostic Challenge; Case Report and Review

The appendicular origin of an intermesenteric abscess is rarely suspected prior to surgery, due to atypical clinical presentation and poor sensitivity of exploratory methods. A 43-year-old male was admitted for recent pain and mild tenderness in the epigastrium, slight emesis, leucocytosis (C-reactive protein was not determined), with no pathological findings on simple abdominal radiological examination (Rx). Abdominal ultrasound (US) and endoscopy were irrelevant. The abdomen became moderately tender, distended; diffuse enteric gas, slightly impaired bowel movement could be demonstrated by a new Rx. CT (oral contrast) was performed in the 3rd day: edematous infiltration of the mesentery and of a left-flank digestive loop (jejunal, sigmoidian?), small-size fluid collection (with extraluminal air-level) and paretic loops in the proximity, but normal wall-appearance of the caecum and its surrounding fat; the CT result was inconclusive (perforated diverticulosis or malignancy?). Barium enema: normal, including the caecum. Installation of vesperal fever, progressive mid-abdominal pain, tenderness and formation of a mass were the rationale for open mid-line laparotomy, discovering a large intermesenteric abscess, secondary to perforated gangrenous intermesenteric appendicitis. Surgical outcome of appendectomy was normal. A high index of suspicion may be suggested by: atypical clinical presentation (fever; ileus; presence or formation of a tender, periumbilical, mass) and CT findings (abscess; extraluminal air; ileus).