A rare case of a retroperitoneal enterogenous cyst with in-situ adenocarcinoma

BACKGROUND Retroperitoneal enterogenous cysts are uncommon and adenocarcinoma within such cysts is a rare complication. CASE PRESENTATION We present the third described case of a retroperitoneal enterogenous cyst with adenocarcinomatous changes and only the second reported case whereby the cyst was not arising from any anatomical structure. CONCLUSION This case demonstrates the difficulties in making a diagnosis as well as the importance of a multi-disciplinary approach, and raises further questions regarding post-operative treatment with chemotherapy.