Renal haemangiomas are rare benign renal tumours, but nearly always cause diagnostic difficulty to the clinician, radiologist and pathologist because of their clinical presentation and ill-defined radiological features. Hence we would like to highlight certain features regarding renal haemangiomas by this case report. In cases of haematuria, the diagnosis of benign renal tumours like haemangiomas needs to be considered as this can save the patient of an extensive radical surgery.

A twenty five year old male was found to have a right lower pole kidney mass incidentally 11/2 years back when he was being managed after an alleged assault. His only complaint was of pain in the back. His biochemical and haematological investigations were within normal limits. Ultra-sonography of abdomen showed a right kidney of size 9.6 x 3.6 cms with hyperechoic mass at the lower pole. The patient did not have any complaints of seizures, hemihypertrophy, glaucoma, cutaneous haemangiomas, etc which are features of Klippel-Trenaunay and Sturge Weber syndromes with which renal haemangiomas are known to be associated with.1 A clinical diagnosis of angiomyolipoma versus renal cell carcinoma was entertained. The patient refused treatment at that point. Subsequently he came 11/2 years later with complaint of one episode of haematuria and radiological investigations showed that lesion had increased in size from 1.7 to 3.5 cms. The patient underwent partial nephrectomy for the same. The surgery was uneventful. The specimen was sent to surgical pathology.

The partial nephrectomy specimen send measured 6x3x2 cms with capsule. The subcapsular surface was smooth. On cut section it showed a brown coloured, soft, spongy area 2.2 cms in size at the corticomedullary junction. It was well demarcated from the surrounding kidney which was unremarkable (Fig. 1).

The histopathology showed congested glomerular capillary tufts, normal tubules, interstitium and blood vessels. The sections from the brown spongy area showed only dilated blood vessels with single layer endothelium amidst oedematous stroma. There was no evidence of intravascular thrombi or papillary necrosis in the surrounding kidney. No fat, smooth muscle, cartilage or bone was noted. Adjacent kidney was otherwise unremarkable. Diagnosis of haemangioma was made (Fig. 2).

Benign renal tumours are generally silent, asymptomatic except for pressure symptoms.2 This is not entirely true for villous papillomas and haemangiomas which can cause haematuria because of their location. Renal haemangiomas are quite rare. In the literature till 1980, only 175 cases were reported.3 There have been no large serial studies ; only scattered case reports are found in the literature making it difficult to determine the exact incidence of renal haemangiomas.4 However they are thought to be more common than generally reported. According to Virchow, renal haemangiomas are second in frequency to liver but are often missed due to their small size and that they tend to collapse in cadaveric state.2 They arise from embryonic rests of unipotent angioblastic cells which fail to develop into vascular system.3 In urinary tract, the kidney is the most common organ for haemangiomas followed by the urinary bladder. They are also known to be associated with various syndromes like Klippel Trenaunay and Sturge Weber syndrome.1

Fig. 1 : Partial nephrectomy showing a well demarcated area at the corticomedullary junction.	Fig. 2 : On right side are seen multiple thin walled vascular channels and normal kidney seen on the left side -200X

These slow growing benign tumours have been reported in a 4 day old child to a 72 year old person with the peak at third and fourth decade.2 Right and left kidneys are equally affected. They occur similarly in males and females. However an angiographic study of renal haemangioma had female preponderance and right kidney more commonly affected than the left.5 In 12% cases they were multiple and in 1% of cases, they were bilateral.2 The size varies from pinhead to 12-15 cms but majority are 1-2 cms in size. 90% are located in the papillae or medullary region whereas 10% are located in the cortical or subcapsular region. There is a single case report of capsular haemangioma also.6 They present with intermittent haematuria, microscopic to gross, pain due to passage of clots. Correct preoperative diagnosis is rarely established.

Radiological investigations like CT scan, ultra- sonography, technetium-99 labelled erythrocyte scan are of some help in making the diagnosis.3 Arteriography reveals characteristic hypervascularity.6

Grossly, these tumours are well circumscribed, soft, spongy, dark red and poorly encapsulated tumours. Histologically, they show various sized endothelium lined spaces filled with red blood cells. They do not communicate with the surrounding vessels. In the old cases they can also show intravascular thrombi and papillary necrosis.3 Cavernous haemangiomas are the most common type. They can also regress spontaneously due to secondary changes like fibrosclerosis.
Partial nephrectomy is the treatment of choice. Occasional case reports of intra arterial embolisation and clipping of feeding artery is also described with good results.7 The procedure however also has side effects like fever, hypertension, kidney dysfunction, sepsis, thromboembolic episodes, mislead embolism, etc. No recurrences have been reported.