[Retroperitoneal benign cyst with osseous metaplasia as the cause of abdominal pain].

A 27-year-old female patient with no previous medical history, presented a computed tomography displaying a calcified retroperitoneal cyst. The patient had experienced occasional abdominal pain in her right side. The tumour was found in the retroperitoneum, was non-adherent to neighbouring organs and was excised laparoscopically without postoperative complications. Histology revealed a benign, cystic mass, with calcification and osseous metaplasia in the cyst wall, and no epithelia. The material of the cyst was amorphic and necrotic. No other retroperitoneal masses alike has been described in the literature.