A 60-year-old Arab woman with a history of Vogt-Koyanagi-Harada (VKH) syndrome is an uveo encephalomeningitis and temporal arteritis for several years was admitted to our department for evaluation of left flank pain and vague abdominal discomfort, low grade fever, and mild urinary disorders. The patient had been treated with corticosteroids (prednisone 20 mg/day), methotrexate 15 mg/weekly and folic acid 5 mg/day for her rare chronic diseases. On admission, the patient appeared well, complained of mild, constant pain in left flank and diffuse abdomen, without nausea, vomiting or diarrhea. She had no symptoms of dyspnea or chest pain; stools were normal. Physical examination revealed good performance status and no respiratory distress. Body temperature was 37.8Cº, blood pressure 130/65 mmHg, heart rate 108/min, and respiratory rate 15/min. Cardiac examination revealed no gallop, murmurs, or friction rub. Lungs were clear. The abdomen was soft, with mild tenderness on deep palpation especially in the left lower quadrant, but without signs of peritoneal irritation. Bowel sounds were present. Laboratory results upon admission revealed leukocyte count 18000/mm3, hemoglobin 12.4 g/dl, and platelets 227000/mm3. Blood glucose 160 mg/dl, sodium, potassium and electrolytes were normal. Kidney and liver function tests including amylase were all in the normal range. Urine test was normal. Chest and abdominal X-ray at admission showed normal findings. Chest X-ray was repeated several hours later because of the appearance of mild chest pain and dyspnea, and revealed an initial small PM (Figure 1). On the subsequent day, the patient complained of worsening of abdominal pain, the abdomen was distended with diffuse tenderness and no bowel sounds were detected. Emergency chest and abdominal CT (computed tomography) was conducted and revealed pneumomediastinum and perforated sigma due to carcinoma with pneumoretroperitoneum (Figure 2,3). The patient was rushed to surgery. In surgery, a mass evading the sigmoid colon with a perforation to its mesentery was found. Hartmann's procedure with resection of the sigmoid colon was performed. The histological results of the mass were consistent with carcinoma in situ. The post-operative management included gradual oral feeding, steroids and secondary closure of abdominal wound and oncologic follow-up. Chest X-ray three days later was normal. The patient was discharged on the 9th day post-operative with the diagnosis of perforated cancer of sigma.