A rare case of extra-adrenal bilateral perirenal and periureteric myelolipoma

Abstract

A 30-year-old immunocompetent female presented with right flank pain since 3 years. MRI revealed a large well-defined T1 and T2 hypointense mildly enhancing lesion in the right anterior pararenal space displacing the right kidney and encasing the right ureter with T2 hyperintense wall thickening of the left renal pelvis and ureter. A provisional diagnosis of solitary fibrous tumour was kept. Bilateral double J stenting was done for hydronephrosis. Surgical debulking of the lesion was done with biopsy from the left periureteral wall thickening and was found to be myelolipoma on histopathological examination. This case is a novel variety of myelolipoma which is lipid poor, extra-adrenal and in bilateral perirenal and periureteric location.

Keywords: hematuria; radiology; urological surgery.

Figure 1

Contrast-enhanced CT abdomen in (A) axial and (B) coronal plane showing enhancing soft tissue density mass in the retroperitoneum in bilateral perirenal and periureteric location along with bilateral hydroureteronephrosis. Bilateral double J stents are seen in situ.

Figure 2

(A) and (B) T2-weighted images and T2 fat-saturated axial image of abdomen at the level of lower pole of kidney demonstrate a well-defined hypointense lesion in the right anterior pararenal space. The lesion abuts the inferior vena cava and displaces the descending colon anteriorly. There is also diffuse T2 hyperintense wall thickening of left ureter (arrow). (C) and (D) T1-weighted Fast Spoiled Gradient-Echo (FSPGR) precontrast and postcontrast images at the same level demonstrate the lesion to be T1 hypointense with mild inhomogeneous enhancement. There is also mild enhancement of the left ureteric wall thickening (arrow).

Figure 3

(A) and (B) T1-weighted Liver Acquisition with Volume Acquisition (LAVA) postcontrast coronal and sagittal images demonstrate the extent of the lesion from the lower pole of right kidney to the level of mid ureter. (C) Diffusion-weighted imaging axial image demonstrates areas of mild restricted diffusion within the lesion on the right side and in the mural thickening of left upper ureter. (D) Heavily T2-weighted maximum intensity projection image in coronal plane demonstrates marked compression of the right proximal ureter with displacement of the mid-ureter laterally. Bilateral hydronephrosis and irregularity of the left ureter are also noted.

Figure 4

Histopathological examination after staining with H&E at (A) 40× magnification and (B) 100× magnification showing sheets of haematopoietic cells, lymphocytes and plasma cells intermixed with mature adipose tissue.

Figure 5

Postoperative contrast-enhanced CT abdomen in (A) axial and (B) coronal plane showing residual lesion in the perirenal and periureteric location on both sides.