Symptomatic presentation and imaging features of a chylous cystic lymphangioma.

A woman in her 60s presenting with 5 days of diffuse abdominal pain was diagnosed preoperatively with a chylolymphatic mesenteric cyst. MRI and CT imaging demonstrated a 5.8 cm unilocular cyst containing a fluid-fluid level within the mesentery. Following an uncomplicated open excision, the lesion was characterised by pathology as a cystic lymphangioma due to the presence of focal smooth muscle and lymphoid tissue in the wall. This case report discusses the radiologic features of rare lymphatic mesenteric cysts that can help guide preoperative diagnosis and highlights that postoperative diagnosis remains definitive. This case also underscores the importance of considering mesenteric cysts as a rare cause of abdominal pain in patients who have non-specific abdominal symptoms and a mass on imaging not associated with any single organ.