Int Urol Nephrol (2009) 41:19–21 DOI 10.1007/s11255-008-9398-8
UROLOGY-CASE REPORT
Renal hilar extramedullary hematopoiesis presenting as incidental unilateral renal hilar mass in adolescent male: a case report Rohini Gupta Æ Ashu Seith Æ Bhuvnesh Guglani
Received: 25 December 2007 / Accepted: 13 May 2008 / Published online: 22 July 2008 Ó Springer Science+Business Media, B.V. 2008
Abstract Extramedullary hematopoiesis (EMH) is a response to erythropoiesis failure in bone marrow, and is mostly encountered in the liver and spleen. Renal involvement is rare and the radiological literature on renal EMH is scant. We report the computed tomography (CT) and magnetic resonance imaging (MRI) findings of one such rare case of renal EMH in a young boy, appearing as a unilateral renal hilar mass. Keywords CT Extramedullary hematopoiesis MRI Renal
Case report A 16-year-old male patient presented with complaints of chronic fatigue and weakness. Hemogram revealed pancytopenia. Bone marrow biopsy revealed extensive marrow fibrosis with paucity of normal hemopoietic elements. X-rays of lumbar spine and pelvis showed a generalized osteosclerosis. Based on these features, a diagnosis of myelofibrosis was made. Computed tomography (CT) scan of the abdomen was done as part of investigational work-up of
R. Gupta A. Seith (&) B. Guglani All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India e-mail:
[email protected]
pancytopenia. CT revealed a soft tissue density mass in the right renal hilum, hypoenhancing to renal parenchyma. Scans in the excretory phase showed soft tissue density areas replacing the renal sinus fat and extending into the pericalyceal spaces, causing extrinsic mass effect on the pelvicalyceal system (Fig. 1). The diagnostic possibilities considered were malignancy such as transitional cell carcinoma, lymphoma, and renal tuberculosis. Based on the clinical diagnosis of myelofibrosis, a possibility of extramedullary hematopoiesis was also kept. MR urogram was done to evaluate for an intraluminal pelvicalyceal component. MRI showed the mass as hypointense on T1W and T2W images. MR urogram showed pelvicalyceal system to be separate from the mass (Fig. 2). This helped in excluding diagnostic possibilities such as tuberculosis and transitional cell carcinoma. In collaboration with the clinical setting of myelofibrosis and incidental renal hilar mass in a patient without any urinary complaints a diagnosis of renal extramedullary hematopoiesis (EMH) was made. The patient was followed up and an ultrasound done 3 months later showed no change in the size of the mass.
Discussion EMH is a response to erythropoiesis failure in bone marrow. It is one of the common features of chronic
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Fig. 1 Sixteen-year-old male patient with myelofibrosis. Axial CT image at the level of kidneys in the excretory phase shows a mass in the right renal hilum. Renal sinus fat is completely replaced by soft tissue which is encasing and splaying the calyces
myeloproliferative disorders, but is rarely encountered in radiological practice [1]. EMH occurs most often in the spleen and liver and occasionally in the lymph nodes. Involvement of other organs, such as the pleura, lungs, GIT, breast, skin, brain, dura, and adrenal glands has also been reported [2, 3]. Only a few reports of renal EMH have appeared in the radiological literature [2]. Renal involvement can be parenchymal, intrapelvic, or perirenal. In the parenchymal type of involvement, the kidneys may either be enlarged diffusely or have small focal lesions. Pelvic involvement is often an extension of parenchymal lesions, but can also be isolated, as in our case. In the perirenal type of involvement, a hypoattenuating mass or nodules are seen either around or encasing the kidneys. The intrapelvic and perirenal type of involvement is usually bilateral [1]. Isolated unilateral renal sinus involvement is very rare. The few reports of renal pelvic EMH describe the lesion as an irregular mass surrounded by sinus fat, appearing isoechoic to renal parenchyma on sonography [4]. CT appearance is that of a homogenous mild to moderately enhancing soft tissue mass encasing the pelvicalyceal system [1, 2, 4]. Similar findings were observed in our case. MR urogram appearance of this entity, however, has not been previously described. The differential diagnosis of a mass encasing the renal pelvis includes transitional cell carcinoma, lymphoma, lipomatosis, renal cell carcinoma, and
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Fig. 2 Sixteen-year-old male patient with myelofibrosis. Coronal restore MIP urogram image shows the hypointense soft tissue extending along the pericalyceal spaces. There is a lack of any intraluminal extension into the pelvicalyceal system
peripelvic cysts. [2]. The most important clinical consequence of EMH involving the kidneys is ureteral obstruction or renal failure due to extensive bilateral parenchymal involvement. These circumstances may necessitate radiotherapy [2, 4]. Conclusion Renal hilar EMH is a rare clinical entity. Imaging diagnosis is usually made by exclusion in the proper clinical setting. This case is unusual because of unilateral involvement. Also, appearance on MR urogram, which was a useful diagnostic tool in our case, has not been previously described.
References 1. Choi H, David CL, Katz RL, Podoloff DA (2004) Case 69: extramedullary hematopoiesis. Radiology 231:52–56
Int Urol Nephrol (2009) 41:19–21 2. Gryspeerdt S, Oyen R, Hoe VL, Baert AL, Boogaerts M (1995) Extramedullary hematopoiesis encasing the pelvicalyceal system: CT findings. Ann Hematol 71:53–56 3. Wright RER (1991) Case report: pararenal extramedullary hematopoietic tissue- an unusual manifestation of myelofibrosis. Clin Radiol 44:210–211
21 4. Tuite MJ, Weiss SL (1991) Ultrasound and computed tomographic appearance of extramedullary hematopoiesis encasing the renal pelvis. J Clin Ultrasound 19:238–240
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