Year : 2008 | Volume
: 19 | Issue : 6 | Page : 976--979
Computed tomographic scan in the diagnosis of bilateral renal lymphangiectasia
Rajul Rastogi, Vaibhav Rastogi
Yash Diagnostic Center, Yash Hospital and Research Center, Civil Lines, Kanth Road, Moradabad (UP), India
Consultant Radiologist, C-002, Upkari Apartments, Plot no 9, Sector 12, Dwarka, Delhi-110078
Renal lymphangiectasia is a rarely reported disorder of lymphatic malformation. Although benign, it may lead to hypertension and renal failure in undetected or undiagnosed cases. Adult polycystic kidney disease is a close mimic. We herewith present a rare case of bilateral renal lymphangiectasia that was strongly suspected on Computed tomographic (CT) scan and confirmed by aspiration cytology. Awareness about this condition will result in early diagnosis, early treatment and reduced morbidity.
|How to cite this article:|
Rastogi R, Rastogi V. Computed tomographic scan in the diagnosis of bilateral renal lymphangiectasia.Saudi J Kidney Dis Transpl 2008;19:976-979
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Rastogi R, Rastogi V. Computed tomographic scan in the diagnosis of bilateral renal lymphangiectasia. Saudi J Kidney Dis Transpl [serial online] 2008 [cited 2021 Jan 17 ];19:976-979
Available from: https://www.sjkdt.org/text.asp?2008/19/6/976/43476
A 20-year-old male patient with fever and vague abdominal pain off and on for 4-6 months was referred to us for contrast enhanced computed tomographic (CT) scan of the abdomen. Clinical examination revealed high blood pressure (150/96) and bilateral palpable kidneys. History of trauma was denied. Laboratory tests were unremarkable. Ultrasound (US) examination done at some other center revealed bilateral nephromegaly, septate, perinephric collection and mild ascites with a provisional diagnosis of bilateral perinephric abscess with possible pyelonephritis.
Contrast enhanced CT scan of the abdomen [Figure 1],[Figure 2],[Figure 3],[Figure 4] revealed bilateral enlarged and slightly deformed kidneys, especially on the right side. The right kidney measured 17.2 × 9.3 cm while the left kidney measured 15.7 × 9.2 cm. There was large, asymmetric perinephric fluid collection on both sides; being larger on the right side. The HU value of the collection ranged from 10-15. Few internal septations and perinephric fascial thickening with no obvious abnormal post-contrast enhancement was noted on either side. There was minute fluid attenuating collection in the renal pelvis bilaterally as well as the retroperitoneum around the great vessels. The renal parenchyma was otherwise normal on both sides. The renal veins were patent bilaterally.No evidence of dilated pelvicaliceal system or any calculus was noted on either side. Mild free fluid was noted in the peritoneal cavity. Rest of the abdomen was unremarkable.
Based on the clinicoradiologic features, a provisional diagnosis of bilateral renal lymphangiectasia with mild ascites was suggested.
Fluid aspiration and cytology followed by drainage under US guidance was performed for confirming the diagnosis and as part of treatment. Approximately 450 mL of chylous fluid was drained from both sides. Microscopic examination revealed only few lymphocytes. The aspirated fluid was rich in protein and contained abundant renin that is specific to kidneys. No organisms were isolated on culture of aspirated fluid. Thus, the diagnosis based on CT findings was confirmed.
The patient was put on diuretics and antihypertensives and was followed-by serial US examinations for six months, which did not reveal any significant increase in perinephric collection or ascites. Although the size of the kidneys was reduced, they did not come to the normal range. The antihypertensives were withdrawn after six months since the patient's blood pressure was within normal limits.
Renal lymphangiectasia (RLM), also known as renal lymphangiomatosis is a rare benign malformation involving the lymphatic system of the kidneys (perirenal, peripelvic and intrarenal lymphatics). It arises as a result of failure of renal lymphatic ducts to drain in to larger retroperitoneal lymphatics, subsequently leading to dilatation of ducts and formation of unilocular or multilocular cystic spaces in the pelvic sinus and perinephric spaces. 
RLM may be seen at any age. Familial association has been reported in some cases.  It may be asymptomatic or may present with non-specific symptomatolgy. The commonest complaints include flank pain, abdominal distension, fever, hematuria, hypertension and rarely, impaired renal function. ,
Imaging studies may give a clue to the diagnosis. Excretory urography, although not diagnostic, reveal normal sized or enlarged kidneys, distortion of the pelvicaliceal system (in intrapelvic collection) and distortion of renal contour (in peripelvic collection).  Ultrasonography is more informative than excretory urography and may be diagnostic. Renal lymphangiectasia is seen as loculated, cystic, septate collection in peripelvic and/or perinephric location with posterior acoustic enhancement.  The kidneys may be normal sized or enlarged and corticomedullary differentiation may be altered. The most important differential diagnosis on ultrasonography is adult polycystic kidneys  and hydronephrosis.  In adult polycystic kidney, the cysts arise from the renal cortex while in renal lymphangiectasia the renal cortex is normal. Similarly, close examination will reveal normal pelvicaliceal system in RLM.
Prior to the advent of CT scan, the diagnosis was usually made at the time of exploratory laparotomy or after nephrectomy. On CT scan, renal lymphangiectasia appears as a well contained, fluid attenuating collections in the peripelvic or perinephric space with or without demonstrable septations with normal renal parenchyma. , When intrarenal lymphatics are solely involved, renal lymphangiectasia may present as simple enlargement of the kidney or even as a solid mass without evidence of any cystic lesion.  The renal shape and contour may be deformed in addition to thickening of perirenal fascia as seen in our case. There was no invasion of the adjacent structures. In addition, the presence of fluid or fluid filled structures in the retroperitoneum adjacent to the great vessels at the level of the renal hilum and crossing the midline as seen in our case, further reinforce the diagnosis of renal lymphangiectasia.  These represent the dilated lymphatic ducts draining the renal and perirenal lymphatics in to larger retroperitoneal lymphatic trunks. The pelvicaliceal system is normal with no evidence of any renal or ureteric calculi. All the other differential diagnosis like nephroblastomatosis, lymphoma and multilocular cystic nephroma can be distinguished from renal lymphangiectasia on CT scan by the fact that all of them involve the renal parenchyma and the former two are solid in attenuation. ,
Magnetic resonance imaging can also diagnose RLM, as the lymphatic collections appear hyperintense on T2W HASTE images and there is reversal of corticomedullary intensity. 
Complications of undiagnosed/untreated cases include hematuria, ascites, hypertension, renal vein thrombosis and impairment of renal function. ,, Fluid aspiration and cytology of the perinephric collection not only confirms the diagnosis but also excludes the presence of urinoma and abscess. Renal origin of lymph can be confirmed by demonstrating high levels of renin as seen in our case. ,
Asymptomatic cases or small renal lymphatic collections are treated conservatively while percutaneous drainage is indicated in large and symptomatic collections causing pressure symptoms or other complications related to RLM.  Partial regression has been reported in neonatal cases  while deterioration has been described during pregnancy. , Recurrent collections can be treated by marsupialization where a communication is made between the collection and the peritoneal cavity.  Ascites and hypertension can be treated with diuretics and antihypertensives. Nephrectomy is reserved for cases with recurring or complicated collections and uncontrollable complications. 
In summary, CT scan can play a very important role not only in the diagnosis of renal lymphangiectasia but also in determining the extent and follow-up, thus reducing the morbidity associated with this condition.
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