[Right lower quadrant abdominal pain--the usual suspects? Diagnosis and therapy of a symptomatic mesenteric cyst]

A 17-year-old male sought medical attention for right lower abdominal pain. At clinical examination an abdominal mass in the right lower abdominal quadrant was accompanied by pain and tenderness in this very region. The febrile patient (temperature axillary: 37.5 °C, rectal: 38.6 °C) was in reduced general health.

Except for an elevated C-reactive protein (CRP: 14.3 mg/dl, normal: < 0.5) laboratory tests were inconspicuous. Abdominal ultrasound showed a hypoechogenic/anechogenic septated mass measuring 7.2 × 10.4 × 15 cm as well as small amounts of fluid. Abdominal computed tomography confirmed these findings. Radiographically there was evidence for appendicitis.

Empiric antibiotic therapy was immediately commenced. Within 48 hours laparotomy was performed showing an abdominal mass which seemed to infiltrate the transverse colon, the ileocolic artery and the mesenteric root. No signs of appendicitis were found. A radical resection of the abdominal mass was performed meeting current standards of oncologic surgery. The postoperative course was favourable. Histopathological investigation showed a mesenteric cyst incorporating a hematoma and tissue with signs of chronic inflammation and granulation.

Mesenteric cysts are rare pathologies occurring most frequently during childhood. They may become clinically overt in case of infection, haemorrhage or secondary intestinal obstruction. In the presented case presented hematoma formation and chronic inflammation had presumably induced peritonitis and clinical signs of appendicitis. Abdominal ultrasound and computed tomography facilitated diagnostic work-up. The patient thereby benefited from a scheduled laparotomy allowing a complete recovery.