Bilateral renal lymphangiectasia

Clinical History

A 43-year-old gentleman presented with complaints of fever for 5 days. No history of loin pain, haematuria or other urinary symptoms. Ultrasound abdomen done elsewhere as a workup for fever revealed bilateral hydronephrosis and perirenal collections. The patient was referred to our hospital for further management.

Imaging Findings

Extensive lobulated fluid collections (1to15HU) were seen in the peripelvic region, insinuating into the right sinus fat bilaterally compressing, narrowing and splaying the pelvicalyceal system. Similar appearing lobulated fluid collections were also seen in the perinephric space bilaterally. Bilateral perinephric and proximal periureteric fat stranding was seen with mild thickening of the pararenal fasciae. These features were in keeping with bilateral renal lymphangiectasia.

Discussion

Renal lymphangiectasia is a rare benign condition caused by dilatation of the perirenal, peripelvic and intrarenal lymphatics. It is known by various names, “renal lymphangiomatosis”, “renal lymphangioma”, “peripelvic lymphangiectasia” and “renal peripelvic multicystic lymphangiectasia” [1]. The exact pathophysiology of this condition is not known but is thought to be due to failure of the perinephric lymphatics to communicate with the main lymphatic system or secondary to congenital or acquired lymphatic obstruction [2].
The majority of patients are asymptomatic and usually diagnosed as an incidental finding. Patients may present with abdominal pain, haematuria and in some instances with hypertension and renal failure. It can occur in both adults and children with no specific age or sex predilection [2, 3].
Plain X-rays show an increase in the renal outline with displacement of the adjacent structures if it is large. Excretory urography shows nephromegaly and hydronephrosis with distortion of the pelvicalyceal system. USG shows multiseptated, thin-walled fluid collections in the perinephric and peripelvic space with normal renal parenchyma [1, 2].
The CT and MRI findings are characteristic. Two patterns of cystic lesions in the renal sinus are described - the peripelvic and parapelvic types. In the peripelvic type, multiple conglomerate intercommunicating small cysts are seen in the renal sinus. The main differential diagnosis is hydronephrosis and CT would be helpful to exclude it by demonstrating non-opacification of these cysts with the excreted contrast medium and extrinsic compression and displacement of the collecting system. In the parapelvic cystic pattern, there is a large single cyst arising from the medial renal parenchymal tissue and encroaching into the renal sinus, mimicking a cortical cyst on imaging [2, 4].
Perinephric fluid collections with septations can be seen enveloping the kidney, representing perirenal lymphangiectasia. Associated retroperitoneal fluid collections/ dilated lymphatics have also been described.
The differential diagnosis includes hydronephrosis, polycystic kidney disease, multilocular cystic nephroma, urinoma and abscess [3].
No treatment is necessary for asymptomatic patients. For symptomatic patients with large collections the options are marsupialisation, nephrostomy or sclerosing therapy. Nephrectomy is reserved for severe cases [3, 5].
Imaging plays an important role in diagnosing this condition with certainty as this condition does not require further workup or treatment.

Differential Diagnosis List

Final Diagnosis

Bilateral renal lymphangiectasia.

URL:	https://www.eurorad.org/case/13018
DOI:	10.1594/EURORAD/CASE.13018
ISSN:	1563-4086