Renal sinus lymphangiectasia: An uncommon entity

Abstract

Renal lymphangiectasia is a benign disorder characterized by cystic dilatation of lymphatic channels in the kidney. It can occur in the perinephric, renal sinus, and intrarenal locations. We describe an uncommon case of renal sinus lymphangiectasia with a characteristic imaging appearance in a 25-year-old female. She presented with loin pain that was managed conservatively.

INTRODUCTION

Renal lymphangiectasia is a benign disorder characterised by cystic dilatation of lymphatic channels in the kidney, due to a drainage anomaly involving the lymphatic system. As the renal sinus is an uncommon site of lymphangiectasia, it requires differentiation from other cystic lesions. It is a rare entity and should be suspected in patients with cystic lesions at this location.

CASE REPORT

A 25-year-old female presented with complaints of nonradiating right mild loin pain for 3 months. Blood investigations were normal, including renal function tests, liver function tests, total leukocyte count, erythrocyte sedimentation rate, and C-reactive protein. The urine examination was also normal. Ultrasound revealed a multiloculated cystic lesion involving the renal sinus of the right kidney, causing splaying of the pelvicalyceal system [Figure 1]. It had no mural nodules or any internal vascularity. Renal echotexture was normal. Contrast-enhanced computed tomography (CT) scan done for further characterization showed multiloculated nonenhancing cystic lesions involving the right renal sinus. There was no evidence of calcification, macroscopic fat, or any enhancing mural nodules within the lesion. There was no opacification of this lesion on the delayed urography phase, however, the pelvicalyceal system was splayed [Figure 2]. An imaging diagnosis of renal sinus lymphangiectasia was made. The patient was managed conservatively with analgesics, in view of the mild symptoms.

Figure 1.

(a) B-mode ultrasound image depicts multiloculated cystic spaces involving the renal sinus (asterisk). (b) No color flow was noted within these cystic spaces on color doppler (asterisk)

Figure 2.

(a) Axial and coronal (b) contrast-enhanced computed tomography images depict multiloculated nonenhancing hypodense lesions of cystic attenuation involving the renal sinus of the right kidney (asterisk). (c) There is no opacification of these lesions on the delayed urography phase (dashed arrow). (d) Delayed coronal maximum intensity projection images show splaying of the renal pelvicalyceal system (arrow)

DISCUSSION

Renal lymphangiectasia (also known as renal lymphangioma) is a rare benign disorder, caused secondary to abnormal dilatation of the lymphatic channels in the perinephric, renal sinus, and/or intrarenal location.[1] It can either present as a fluid collection or a multiloculated cystic lesion. It represents ~1% of all lymphangiomas and does not have a gender or age predilection.[2] Perinephric lymphangiectasia is the most common typically presenting with perinephric fluid collections enveloping the kidney. Parapelvic or renal sinus lymphangiectasia is less common, involving the medial renal tissue.

Most cases are diagnosed incidentally; however, patients can present with flank pain or hematuria. It can rarely be associated with renal vein thrombosis and hypertension; however, usually, renal function is maintained. If imaging findings are not diagnostic, aspiration can be performed (yielding chylous fluid); however, aspiration might be difficult in centrally located lesions, like in the renal sinus. Treatment is generally not needed because of the benign nature of the disease, however, in symptomatic or complicated cases, nephrectomy, sclerotherapy, percutaneous drainage, or marsupialization can be done.[3] Percutaneous drainage can be done in patients with symptoms secondary to mass effect, although the risk of recurrence is high. In addition, injection of sclerosants, such as doxycycline or povidone–iodine-based solutions, reduces the chances of recurrence. However, multiple sessions may be required in multiloculated lesions.[4]

Renal sinus lymphangiectasia can often be misdiagnosed as hydronephrosis, in view of the similar imaging appearance and location. The delayed CT urography phase will show no opacification of the cystic areas in renal sinus lymphangiectasia, in contrast to hydronephrosis. Multilocular cystic nephroma (MCN) closely mimics renal sinus lymphangiectasia, with contrast-enhanced ultrasound (CEUS) helping to make this distinction. In MCN, there is a focal multiloculated cystic mass with septae in the parapelvic region, and these septae show an abnormal pattern of enhancement on CEUS.[5] In renal sinus lymphangiectasia, these “septae” actually represent the normal renal parenchyma (which is compressed in between the cystically dilated lymph channels), which will show normal enhancement, similar to the rest of the kidney on CEUS.

CONCLUSION

Radiology plays a vital role in suggesting the diagnosis of renal lymphangiectasia affecting the management and follow-up.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.