Abdominal Imaging

, Volume 31, Issue 6, pp 719–721 | Cite as

Unusually large cisterna chyli: US and MRI findings

  • S. Tamsel
  • S. S. Ozbek
  • A. Sever
  • N. Elmas
  • G. Demirpolat
CASE REPORT

Abstract

We report a rare appearance of cisterna chyli appearing as a giant cystic structure on routine abdominal ultrasonography (US). Diagnosis was established with color Doppler US and after magnetic resonance imaging. This report describes an unusual appearance of the cisterna chyli that radiologists should be familiar with, especially on the routine conventional gray-scale US to avoid mistaking it for a pathologic condition.

Keywords

Large cisterna chyli Imaging findings 

The cisterna chyli is a dilated lymphatic sac in the retroperitoneal space, usually to the immediate right of the abdominal aorta, and represents the origin of the thoracic duct. It is seen in approximately 50% of lymphangiographic studies [1] and 20% of autopsies [2]. The cisterna chyli is joined by two lumbar and intestinal lymphatic trunks that originate at the level of the L1-L2 vertebral body, after which it continues in the cephalic direction as the thoracic duct [2]. Despite this classic description, the cisterna chyli has a highly variable appearance. The appearance of the normal cisterna chyli and variations in normal anatomy were described by Pinto et al. [3] who examined 200 patients with magnetic resonance imaging (MRI) using highly fluid-sensitive sequences.

Case report

A 62-year-old woman was examined by abdominal ultrasonography (US) because of nonspecific gastrointestinal symptoms such as nausea. US evaluation showed an anechoic cystic structure in the retroperitoneal space adjacent to the anterolateral aspect of the abdominal aorta (Fig. 1). It was also close to the right renal artery and extended to the preaortic space (Fig. 2). The greatest dimension of the cystic lesion was approximately 4 cm. Color Doppler US (CDUS) was also performed because of the cystic appearance and close location of the lesion to the main abdominal vascular structures. CDUS revealed the nonvascular origin of the cystic lesion. After US examination, MRI was performed with half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence on a 1.5-T system (Magnetom Vision; Siemens, Erlangen, Germany) with a body phased array coil. Images obtained with HASTE sequence clearly depicted an unusually large cisterna chyli as a saccular structure in retroperitoneal prevertebral locations with high signal intensity of fluid (Fig. 3). Maximum intensity projection reconstruction images were also obtained at the workstation by using source images that improved visualization of the afferent trunks joining with the inferior part of the cisterna chyli (Fig. 4). The greatest measurement of the cisterna chyli was approximately 4.2 cm in craniocaudal length, 2.5 cm in anteroposterior diameter, and 3.2 cm in transverse diameter.
Figure 1

Axial sonogram through the abdominal cavity shows a saccular anechoic cystic structure (c) adjacent to the right aspect of the abdominal aorta (AO). Note the beak-shaped extension of the cystic structure toward the prevertebral space.

Figure 2

Sonographic image obtained in the midsagittal plane demonstrates the close location of the cystic structure (c) to the right renal artery.

Figure 3

Axial T2-weighted MR image acquired with a HASTE sequence (repetition time 1100 ms, echo time 86 ms, echo train length 256, matrix 256 × 256, slice thickness 6 mm, field of view 30 to 40 cm, one acquisition) shows a partially rounded structure with high signal intensity (arrow) anterior to the vertebral column at the level of the renal hilum.

Figure 4

Sagittal maximum intensity projection image reconstructed from image data obtained with HASTE sequence clearly depicts the cisterna chyli as a saccular structure at a prevertebral location with a homogeneously high signal intensity similar to that of cerebrospinal fluid. Note the afferent lymphatic tubular channels (arrow) joining with the inferior part of the cisterna.

Discussion

The appearance of the cisterna chyli on MRI has seldom been described [3, 4, 5, 6]. To our knowledge, an unusually large cisterna chyli with an anteroposterior or transverse diameter larger than 2 cm is rare and limited to the study reported by Lee and Cassar-Pullicino [4]. The giant cisterna chyli described in their study consisted of contrast-enhanced MRI with US and computed tomographic correlation in three patients [4]. The craniocaudal dimension of the cisterna chyli was reported as 5 cm in two patients and 7 cm in another, with a transverse diameter of 2 cm in these patients. In a more recent study, Erden et al. [6] evaluated the detectability, configuration, location, and dimensions of the cisterna chyli on MRI in 125 patients and reported that the greatest dimensions in the craniocaudal, anteroposterior, and transverse diameter of the cisterna chyli were 10, 1, and 1 cm, respectively. The cisterna chyli with a transverse diameter of 3.2 cm and an anteroposterior diameter of 2.5 cm described in our patient appears to be very rare and not reported previously in the literature to our knowledge.

Pinto et al. [3] identified the cisterna chyli in 30 of 200 patients (15%) who were evaluated with routine abdominal MRI protocols that include HASTE sequence. They described the cisterna chyli as a variably shaped, fluid-filled structure in the retrocrural space and reported that the maximum caliber was 2.3 cm. In our case, the cisterna chyli appeared as a saccular cystic structure with a greatest dimension of approximately 4.2 cm in the caudocephalic direction.

An unusually large cisterna chyli may mimic other pathologic conditions of the retroperitoneum at conventional gray-scale US, and it may be mistaken for a retrocrural lymph node on computed tomographic images. However, depiction of fluid content of the cisterna chyli continuous with the afferent lymphatic trunks permits its accurate identification on MRI.

Radiologists should be familiar with anatomic variations, including an unusually large size, of the cisterna chyli to avoid mistaking it for a pathologic entity.

References

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Copyright information

© Springer Science+Business Media, Inc. 2005

Authors and Affiliations

  • S. Tamsel
    • 1
  • S. S. Ozbek
    • 1
  • A. Sever
    • 1
  • N. Elmas
    • 1
  • G. Demirpolat
    • 1
  1. 1.Department of RadiologyEge University HospitalBornovaTurkey

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