CASE REPORT

Int J Clin Oncol (2008) 13:166–168 © The Japan Society of Clinical Oncology 2008DOI 10.1007/s10147-007-0700-z

E. Takaoka (*) · N. Sekido · M. Naoi · K. Kawai · T. Shimazui · H. AkazaDepartment of Urology, Institute of Clinical Medicine, 1-1-1 Tennodai, Tsukuba, Ibaragi 305-8575, JapanTel./Fax +81-29-853-3223e-mail: tach-tech-voice@mvb.biglobe.ne.jp

K. MatsuedaDepartment of Radiology, Institute of Clinical Medicine, University of Tsukuba, Ibaragi, Japan

Ei-Ichiro Takaoka · Noritoshi Sekido · Makito Naoi Kiyoshi Matsueda · Koji Kawai · Toru Shimazui Hideyuki Akaza

Cavernous hemangioma mimicking a cystic renal cell carcinoma

because the confi guration of the tumor had changed within a few years.

Case report

A 69-year-old man was hospitalized for treatment of a left renal tumor. Originally, in April 2000, he was diagnosed with a left renal cyst by computed tomography (CT). Sub-sequently, routine abdominal ultrasound examinations had been performed every 6 months. However, in September 2004, ultrasound revealed a smooth-bordered hypoechoic tumor that contained a papillary echogenic component, and cystic renal cell carcinoma was suspected. He was a former smoker, and his family history was not remarkable. He had no history of asymptomatic gross hematuria. There were no particular physical fi ndings, such as fl ank pain. Routine hematology, blood chemistries, and urinalysis showed no abnormality. Urine cytology studies and cultures were neg-ative. CT with contrast media had demonstrated a simple cyst in the left kidney in April 2000 (Fig. 1b). The wall of the tumor was slightly thick for a simple cyst. In September 2004, plain CT showed a low-density mass at the site of the simple cyst. The mass did not contain lipids or areas of cal-cifi cation on plain CT. In the arterial phase, the thick wall of the mass and an internal solid papillary component were visible (Fig. 1b). In the portal phase, the papillary compo-nent was further enhanced. However, a nonenhanced lesion inside the mass was also visible in the portal phase, and it looked like a unilocular cystic mass (Fig. 1c). The contrast medium in the papillary component was not washed out in the late phase. Magnetic resonance imaging (MRI) was also performed. The thick wall had very low intensity on both T1-weighted (T1WI) and T2-weighted (T2WI) images and was barely enhanced. The internal solid papillary compo-nent showed a low intensity, equivalent to that of the renal cortex, on T1WI, high intensity on T2WI, and was well enhanced on gadolinium-enhanced T1WI (Fig. 2). Power doppler sonography revealed that the papillary component had a vascular system.

Received: July 17, 2006 / Accepted: June 23, 2007

Abstract A 69-year-old man was hospitalized for treatment of a left renal tumor. The tumor had originally been dem-onstrated as a simple renal cyst 4 years before. However, the size of the tumor decreased, and at the time of hospi-talization, the tumor showed a solid, papillary component that was enhanced by contrast medium on computed tomog-raphy (CT) and had high signal intensity on T2-weighted magnetic resonance imaging (MRI). We diagnosed this tumor as a cystic renal cell carcinoma of the left kidney, cT1aN0M0, arising from the epithelium of a renal cyst, and performed a left partial nephrectomy. The pathological diagnosis was cavernous hemangioma of the left kidney. Generally, it is diffi cult to diagnose a cavernous hemangi-oma of the kidney preoperatively. This case is unusual because the confi guration of this tumor changed within a few years. When we fi nd a renal cyst with a solid compo-nent, renal cavernous hemangioma arising from the cyst wall should be considered in the differential diagnosis, and a conservative surgical approach should be considered.

Key words Cavernous hemangioma · Kidney

Introduction

Cavernous hemangioma of the kidney is an uncommon, benign vascular tumor that is rarely diagnosed preopera-tively. About 200 cases have been reported in the literature since Virchow fi rst described it in 1867.1 We present a case of cavernous hemangioma of the kidney which was unusual

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We diagnosed this tumor as a cystic renal cell carcinoma of the left kidney, cT1aN0M0, arising from the epithelium of a renal cyst. We performed a left partial nephrectomy. The cut surface of the resected tumor had a fi brous capsule, hemorrhage, and necrotic tissue in the central area, and it had a solid, papillary component.

In the microscopic fi ndings, the solid, papillary compo-nent revealed vascular networks that were not lined with atypical endothelial cells (Fig. 3). The pathological diagno-sis was cavernous hemangioma of the left kidney.

Discussion

Hemangiomas are benign vascular tumors that probably arise from embryonic remains of unipotent angioblastic cells.2 A distinction is made between capillary and cavern-ous forms. Although a renal hemangioma may be found in any part of the kidney, the most frequent location is the tip of the papilla. The submucosal region, papilla, and medulla

account for 90% of all anatomical locations, and the renal parenchyma and capsule account for the rest.3 More than 80% of renal hemangiomas develop in a unilateral kidney as a solitary mass. There is no predilection for sex or lateral-ity.3 The clinical symptoms of this disease range from none to gross hematuria and sometimes colic due to the passage of blood clots.2 The radiological features of this tumor are not well described, and reports of large studies are lacking. Descriptions of renal cavernous hemangiomas on angiogra-phy have included a normal appearance,4 a hypervascular mass producing varying degrees of caliceal deformity, and a hypervascular mass with rapid arteriovenous shunting.5 The sonographic fi ndings are nonspecifi c, and have been reported as hyperechoic tumor1 or hypoechoic tumor.6 Power doppler sonography revealed a normal renal vascu-lar pattern rather than a pattern specifi c to hemangioma.6 These fi ndings may mimic more common tumors of the kidney, including renal cell carcinoma and transitional cell carcinoma On the CT fi ndings, renal cavernous hemangi-oma is reported as a mass that is isodense relative to the renal cortex during the excretory phase, and as a homoge-

a b c

Fig. 1a–c. Computed tomography (CT) of the present patient. (a) Originally, the tumor looked like a simple cyst in the left kidney. Four years later, the thick wall of a mass and an enhanced internal solid

papillary component were visible in the arterial phase (b), and the portal phase (c) showed a nonenhanced lesion, inside the mass, which looked like a unilocular cystic mass

Fig. 2. Magnetic resonance imaging (MRI) in the present patient. The internal solid papillary component was well enhanced on gadolinium-enhanced T1- weighted image

Fig. 3. Pathological fi ndings in the present patient. The solid papillary component revealed vascular networks that were not lined with atypi-cal endothelial cells

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neously enhanced mass with peripheral hypoenhancement during the portal phase.6 However, two cases were reported as a mass that was not enhanced by intravenous contrast material. The reason for this might be hemorrhaging in the tumor.3 There is only one case report that describes the MRI appearance of this tumor. MRI showed the lesion, best seen on T2-weighted (T2 WI) sequences, as a hyperintense mass with some fl ow voids. After contrast administration, the mass became fi lled with the contrast material.6 Histo-logically, the tumors have a dense network of thick-walled vessels lined with typical endothelial cells, and sometimes the tumors have hemorrhages.2 Renal cavernous hemangi-oma is seldom diagnosed preoperatively, and it is therefore impossible to recommend a specifi c treatment. Generally, surgery is considered when the tumor causes symptoms such as life-threatening hemorrhage, or when it is diffi cult to distinguish the lesion from a disease such as carcinoma, which requires nephrectomy.3

In our patient, a comparison of the radiological and pathological fi ndings revealed that the part that was hypo-echoic and not enhanced by contrast media on CT, and that had a low signal intensity on T2WI MRI was consistent with the hemorrhagic and necrotic part.

The papillary part, which was hyperechoic, was enhanced by contrast media on CT, and had a high signal intensity on T2WI MRI, which is compatible with the hemangiomatous part. In addition, interestingly, the tumor was originally demonstrated as a simple renal cyst. We thought it unlikely to be a cavernous hemangioma at that time.

Later, the size of the tumor decreased, and the tumor showed a solid, papillary component that was enhanced by contrast medium on CT and had high signal intensity on T2WI MRI. Regression of the tumor may occur because hemangioma can regress spontaneously as a result of fi bro-sis.2 In addition, we offer two hypotheses. One is that the cavernous hemangioma arose from the renal cyst wall hem-

orrhaging into the cyst. The other is that the tumor, which resembled a renal cyst, was originally a cavernous heman-gioma. Usually, a cavernous hemangioma is reported as a solid mass with or without hemorrhage. There is only one case report in the literature of cavernous hemangioma that had originated from a cyst wall.7 These speculations cannot be confi rmed by pathological fi ndings because a specimen can be obtained only once, and thus cannot explain the time course of the development.

In conclusion, the preoperative diagnosis of cavernous hemangioma remains diffi cult because this tumor produces no particular clinical symptoms, blood or urine fi ndings, or images on radiological studies, including sonography, CT, and MRI. When a renal cyst with a solid component is detected, renal cavernous hemangioma should be consid-ered in the differential diagnosis and nephron-sparing surgery should be considered.

References

1. Numan F, Berkmen T, Korman U, et al. (1993) Cavernous heman-gioma of the kidney. Case report. Clin Imaging 17:106–108

2. Jahn H, Nissen HM (1991) Hemangioma of the urinary tract: review of the literature. Br J Urol 68:113–117

3. Lee HS, Koh BH, Kim JW, et al. (2000) Radiologic fi ndings of renal hemangioma: report of three cases. Korean J Radiol 1:60–63

4. Gordon R, Rosenmann E, Barzilay B, et al. (1976) Correlation of selective angiography and pathology in cavernous hemangioma of the kidney. J Urol 115:608–609

5. Stanley RJ, Cubillo E, Mancilla-Jimenez R, et al. (1975) Cavernous hemangioma of the kidney. AJR Am J Roentgenol 125: 682–687

6. Geenen RWF, den Bakker MA, Bangma CH, et al. (2004) Sonog-raphy, CT, and MRI of giant cavernous hemangioma of the kidney: correlation with pathologic fi ndings. AJR Am J Roentgenol 182:411–414

7. Summers JL (1977) Hemangioma in the wall of a cyst. J Urol 118: 529–530