Chylous Mesenteric Cyst in Asymptomatic 60 Year-Old Woman

Abstract

Purpose: 60-year-old female presented for further evaluation of a large mesenteric cyst noted incidentally on routine abdominal CT scanning performed during a preoperative evaluation for elective kidney donation. Clinically, she denied gastrointestinal symptoms. Past medical history was significant for recurrent episodes of diverticulitis, and hyperlipidemia. No prior history of pancreatitis. No significant family history of malignancy. Past surgeries included a transabdominal hysterectomy and three caesarean sections, all greater than twenty years prior to the current presentation. She reported two motor vehicle accidents in the remote past associated with unspecified abdominal trauma, managed conservatively. Labs showed normal hemoglobin, electrolytes, TSH, and liver function tests. Abdominal CT scan showed a 6.7 × 2.6 multilobulated, septated cystic lesion at the mesenteric root, inferior to the third portion of the duodenum, interpreted as a mesenteric cyst or potentially enteric cyst. The patient underwent endoscopic ultrasound guided biopsy of the mesenteric cyst. Cytology from multiple fine-needle aspirates was negative for malignancy, but showed abundant histiocytes and chronic inflammation. No epithelial cells were present. Approximately 10 cc of milky yellow fluid was aspirated from the cyst. CEA and CA 19-9 levels from the cyst fluid were unremarkable, but revealed elevated cholesterol and triglycerides, 256 mg/dL and 1131 mg/dL, respectively, consistent with a mesenteric chylous cyst. Discussion Mesenteric cysts are rare and frequently cause abdominal pain, distension, or intestinal obstruction due to the mass effect. Chylous mesenteric cysts, notably, are exceedingly rare with few case reports in the literature. Constitutional symptoms of malaise, fatigue, fever, and weight loss may develop though are infrequent. Mesenteric cysts are often large in size, cause acute or chronic symptoms, though have a very low malignant potential and associated morbidity. Underlying etiologies include congenital malformations and scarring of the mesenteric lymphatics due to chronic inflammatory states e.g. mesenteric panniculitis. Cysts are generally unilocular though may present with multiple loculations and, most importantly, lack solid components. Surgical excision is the recommended therapy in clinically symptomatic patients. Cyst drainage alone is not recommended, due to the high frequency of recurrence. Given the absence of clinical symptoms in this case, a conservative approach with observation was recommended.