Dilated Cisterna Chyli: A Potential Mimicker of Lymphadenopathy

  

Axial (top) and coronal (bottom) contrast-enhanced CT images
demonstrate a retrocrural fluid-filled tubular structure with imperceptible walls
 (black arrows), the classic imaging features of a cisterna chyli

Coronal T2-weighted MRI shows the tubular cystic structure of the cisterna chili
and it's continuity with the thoracic duct (white arrow)

• The cistern chyli is a dilated lymphatic sac ommonly located in the right retrocrural region, at the level of L1-L2, extending 5-7 cm in CC dimension. It classically receives draining lymph from two lumbar trunks and an intestinal trunk, and continues cephalad as the thoracic duct

• Can enhance on delayed MRI >5 min

• Has an average size of 7.4 mm in the AP dimension, although some authors consider it dilated when ≥6 mm

• Dilatation can be secondary to lymphatic damage from prior gastroesophageal or retroperitoneal surgery, uncompensated cirrhosis, hypoalbuminemia, lymphangioleiomyomatosis, elevated central venous pressure, and biliary obstruction

• Size changes can vary depending on phase of respiration, hydration, and lower thoracic duct peristalsis

• Important to know of this entity because it can mimic retrocrural lymphadenopathy in the oncologic setting

• Mulitplanar reformations and MRI can help demontrsate the tubular cystic nature of the cistern chyli and its continuity with the thoracic duct 

References 

1. Rosenberger A, Abrams HL (1971) Radiology of the thoracic duct.Am J Roentgenol Radium Ther Nucl Med 111:807–820
2. Pinto PS, Sirlin CB, Andrade-Barreto OA, et al. (2004) Cisternachyli at routine abdominal MR imaging: a normal anatomicstructure in the retrocrural space. Radiographics 24(3):809–817 
3. Smith TR, Grigoropoulos J (2002) The cisterna chili: incidence and characteristics on CT. Clin Imaging 26:18–22
4. Arrive ́ L, Azizi L, Lewin M, et al. (2007) MR lymphography ofabdominal and retroperitoneal lymphatic vessels. AJR189(5):1051–1058
5. Gollub MJ, Castellino RA (1996) The cisterna chyli: a potentialmimic of retrocrural lymphadenopathy on CT scans. Radiology199(2):477–480 

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