Unusual renal tumour: multilocular cystic renal cell carcinoma

Abstract

Multilocular cystic renal cell carcinoma (MCRCC) is a rare presentation of renal cell carcinoma. Most patients are asymptomatic and frequently MCRCCs are detected incidentally. MCRCCs have good prognosis because of their low malignant potential. We report a case of a 39-year-old woman who presented with mild right flank pain and normal laboratory data. On imaging examinations, a Bosniak III cystic lesion was detected in the lower third of the right kidney. She underwent right partial nephrectomy and histopathology showed a multilocular cystic renal cell carcinoma Fuhrman grade 1. In this article, we also present a review of the literature on MCRCC, highlight the correlation of the pathological and imaging characteristics of these low aggressive renal lesions, and underscore the importance of their recognition to prevent unnecessary radical surgery.

Figure 1

Abdominal ultrasound of a partially exophytic well-defined lesion detected in the lower third of the right kidney (arrows). This neoplasm showing heterogeneous echogenicity with anechoic cystic areas separated by hyperechoic solid septa.

Figure 2

Abdominal CT before (A) and after (B–F) intravenous contrast administration. (A) On axial unenhanced CT images, this right renal lesion shows well-defined limits, predominant hydric density and a few fine septal calcifications. (B–D) Axial and (E and F) coronal CT images after administration of intravenous contrast demonstrate the multiloculated morphology of this tumour with multiple cysts separated by multiple thick and irregular septa showing measurable enhancement (B–E). No solid nodules were detected. These features were consistent with a Bosniak type III lesion. This patient also showed inferior vena cava duplication, a rare congenital vascular anatomic variation (*).

Figure 3

Axial (A) and coronal (B) abdominal MR T2-weighted images showing a partial exophytic lesion in the lower third of the right kidney parenchyma, well-delineated by a hypointense rim, multiloculated, and composed of multiple hyperintense cysts separated by thick and irregular hypointense septa, without solid nodules.

Figure 4

(A) On T1-weighted images, this right renal neoplasm showing similar signal intensity to the adjacent renal parenchyma and a peripheral hypointense rim. On (A) in-phase and (B) out-of-phase T1-weighted images, the lesion has no signal loss, excluding the presence of intracellular fat component.

Figure 5

On fat supressed T2-weighted images, this renal lesion showing no signal intensity loss, excluding the presence of macroscopic fat.

Figure 6

On dynamic contrast-enhanced images, the tumour showing enhancement of its wall and septa. No enhancing solid nodules were detected.

Figure 7

On diffusion study, this renal tumour was (A) hypointense on high b values (b1000) and (B) hyperintense on the ADC map, showing no restricted diffusion.

Figure 8

A photograph of the gross specimen of right partial nephrectomy showing complete excision of an encapsulated renal tumour, displaying a multilocular appearance with multiple cysts of different sizes, corresponding to 70% of the tumour, separated by multiple fibrous septa, which constitute the tumour solid component, corresponding to the remaining 30% of the tumour.

Figure 9

Photomicrograph of histological section reveals (A) (H&E, ×100) multiple cysts of different sizes and multiple fibrous septa. (B) (H&E, ×200) A thin epithelial layer of neoplastic clear cells with uniform nuclei and clear cytoplasm lined the cysts walls and fibrous septa. These clear cells showed low Fuhrman grade. No solid expansible nodules were detected.