A 13-year-old young female presented to the emergency department with abdominal pain, constipation and repeated bouts of vomiting for the last three days. The pain was sudden in onset, colicky in character and intermittent in onset. Her past medical history showed that she was treated with anti-tuberculous therapy for pulmonary tuberculosis. She took anti-tuberculosis treatment for nine months and completed this course two years back. General physical examination showed a heart rate of 110 beats/min and a BP of 90/60 mmHg with obvious clinical signs of dehydration. Abdominal examination revealed mild distension and tenderness with a 5 x 10 cm intra-abdominal mass in the upper abdomen. Bowel sounds were exaggerated. Laboratory results showed a hemoglobin level of 8.7 g/dl and a Serum Creatinine of 1.2 mg/dl. X-ray abdomen showed air-fluid levels in the small bowel. Ultrasonography of the abdomen revealed a 15 x 18 cm hypoechoic mass in the center of the abdomen. These findings were suggestive of small bowel obstruction secondary to abdominal tuberculosis. The patient was resuscitated, and surgical exploration was planned. Exploration revealed a huge cyst with dimensions of 24 cm x 20 cm x 16 cm, arising from the retroperitoneum, projects into transverse mesocolon and displacing loops of the small intestine (Fig. 1, Fig. 2). Cyst contained three liters of serous fluid. Complete excision was possible without resection of the associated organs. The specimen was sent for histopathology. Inspection of the specimen revealed 24 x 12 x 10 cm cyst, with a smooth outer surface and an irregular inner surface. Microscopic examination confirmed the diagnosis of the benign retroperitoneal cyst was made. There was no atypia or malignancy. She was discharged on her 3rd postoperative day. Post-op recovery was uneventful. The patient remains asymptomatic during the two years follow up period.