Year : 2006 | Volume
: 16 | Issue : 3 | Page : 367--368
CT of diffuse fatty infiltration of renal parenchyma secondary to bilateral giant angiomyolipomas- a case report
NS Rawat, A Negi, BB Thukral, NC Saxena
Department of Radiodiagnosis & Imaging, Vardhman Mahavir Medical College & Safdarjung Hospital, New Delhi, India
N S Rawat
25 - B, Pocket A - 10, Kohinoor Apartments, Kalkaji Extension, New Delhi - 110019
|How to cite this article:|
Rawat N S, Negi A, Thukral B B, Saxena N C. CT of diffuse fatty infiltration of renal parenchyma secondary to bilateral giant angiomyolipomas- a case report.Indian J Radiol Imaging 2006;16:367-368
|How to cite this URL:|
Rawat N S, Negi A, Thukral B B, Saxena N C. CT of diffuse fatty infiltration of renal parenchyma secondary to bilateral giant angiomyolipomas- a case report. Indian J Radiol Imaging [serial online] 2006 [cited 2020 Sep 19 ];16:367-368
Available from: http://www.ijri.org/text.asp?2006/16/3/367/29019
Tuberous sclerosis is an autosomal dominant disorder characterized by a classical clinical triad of epilepsy, mental retardation and adenoma sebaceum. It is associated with multiple organ and skeletal abnormalities ,. Renal angiomyolipomas are uncommon benign neoplasms that occur in upto 40-80% of tuberous sclerosis patients ,. Uncommonly they become large in size and have a propensity for spontaneous hemorrhage .
We report a rare case of tuberous sclerosis where patient had characteristic cerebral lesions and bilateral renal angiomyolipomas completely replacing renal parenchyma by diffuse fatty infiltration. In addition, patient had a splenic angiomyolipoma.
A 32 year old female presented to our hospital with dull aching pain since four months & recurrent urinary tract infection since four weeks. On detailed history taking, her family revealed that the patient had episodes of convulsions since childhood for which she took treatment on and off. Physical examination revealed firm masses in bilateral lumbar region occupying almost the whole of abdomen extending from hypochondrium to the iliac region. Laboratory investigations including renal function tests were normal. Chest skiagram was normal. Ultrasound abdomen revealed huge renal masses extending from the hypochondrium to the iliac fossae. These masses were markedly echogenic with no evidence of normal renal parenchyma noted within them. CT scan of abdomen showed bilateral massive renal masses occupying the whole of abdomen and pelvis and causing anterior displacement of bowel loops. Bilateral masses showed low attenuation value suggestive of predominant fat component completely replacing the renal parenchyma. [Figure 1]
Right-sided mass measured 29 X 16 X 9 cms. in size Left-sided mass measured 27 X 15 X 8 cms. in size
Contrast enhanced scans showed patchy & heterogeneous enhancement in the soft tissue & vascular component of the mass lesion [Figure 2]. Findings were diagnostic of angiomyolipomas. Normal excretion of contrast media was seen on both sides. Splenomegaly was noted and a well-defined rounded low density lesion with fat and hemorrhagic attenuation value was seen within it. The lesion showed mild enhancement along the periphery [Figure 3].Possibility of chronic hematoma caused by repeated bleeding from a small angiomyolipoma in spleen was considered. CT scan of brain showed multiple small-calcified subependymal and periventricular nodules [Figure 4]. As the patient was unwilling for surgery, she was put on conservative management and was advised to come for regular clinical follow up.
Tuberous sclerosis is an autosomal dominant disorder often associated with chromosome 9 abnormalities. It is characterized by a classical clinical triad of epilepsy, mental retardation and adenoma sebaceum ,. However due to incomplete penetrance, symptomatology may range from isolated organ involvement to involvement of multiple organs with hamartomatous lesions particularly in brain, skin, retina, heart & kidneys ,.
Hamartomatous lesions in the brain; typically in the form of subependymal, periventricular calcified nodules are present in more than 50 % of cases .Renal involvement occurs in 40-80 % of patients . Renal angiomyolipomas are uncommon benign neoplasms that are composed of mature or immature fat, thick walled blood vessels & smooth muscle elements in varying proportions ,. They compress and distort the renal parenchyma and collecting system but are not usually invasive . Angiomyolipomas may affect the perirenal fat and local lymphatic vessels and the presence of tumors in extrarenal sites is considered multicentric and not metastatic. As for clinical manifestations, the main symptom is abdominal pain. Other signs and symptoms are palpable mass, hemorrhage, hematuria, nausea and vomiting, systemic arterial hypertension, anemia, fever, shock, renal failure and urinary infection . On ultrasound, the echogenicity of angiomyolipomas is similar to that of renal sinus fat, interspersed with some less echogenic areas. Correlation of ultrasound with histopathology suggests that the echogenic areas correspond primarily to fatty portions of angiomyolipoma, the less echogenic areas to myomatous or vascular elements or to focal hemorrhage while the echo poor lesions are due to hemorrhage . Currently CT is unusually diagnostic due to the attenuation coefficient -10 to -80 HU produced by fatty component of tumor . If fat is depicted at CT, histological proof is not necessary for diagnosis of angiomyolipoma ,. Since with ultrasound and CT scan there is an improvement in the preoperative diagnosis of angiomyolipoma, percutaneous needle biopsy and surgery for diagnosis should be avoided in asymptomatic individuals for the risk of massive hemorrhage . The current trend is to treat asymptomatic patients conservatively with regular clinical and radiological follow up and to advise nephron sparing surgery and /or intraarterial embolization for those patients with pain, hemorrhage, complex lesions and enlarging tumors ,.
Splenic angiomyolipomas are a very rare association of tuberous sclerosis with only a few isolated case reports in the literature. Similar low density lesions on CT scan with mild enhancement along the periphery can be seen in chronic hematoma caused by repeated bleeding from a small angiomyolipoma in spleen . Although isolated case reports of giant renal angiomyolipomas are seen in literature, but diffuse fatty infiltration completely replacing the renal parenchyma in massively enlarged kidneys in association with a splenic lesion is quite rare ,,,
|1||Evans JC, Curtis J. The radiological appearances of tuberous sclerosis. The British Journal of Radiology 2000; 73: 91-98.|
|2||Arslan A, Ciftci E, Cetin A, Selcuk H, Demirci A. Tuberous Sclerosis: Ultrasound, CT and MRI features of two cases with multiple organ involvement. Australasian Radiology 1998; 42: 379-382.|
|3||Jackson DMA, Collins CD, Cosgrove DO. Case Report: Diffuse fatty infiltration of the renal parenchyma secondary to bilateral angiomyolipomas- features on ultrasound & computed tomography. British Journal of Radiology 1995; 68: 318-320.|
|4||Ashebu S, Dahniya M, Elshebiny Y, Varro J and Alkhawari H. Giant bleeding renal angiomyolipoma: Diagnosis & Management. Australasian Radiology 2002; 46: 115-118.|
|5||Schneider-Monteiro ED, Lucon AM, FigueiredoAA, Rodrigues Junior AJ, Arap S. Bilateral giant renal angiomyolipoma associated with hepatic lipoma in a patient with tuberous sclerosis. Rev Hosp Clin Fac Med Sao Paulo. 2003 Mar-Apr; 58(2):103-8. Epub 2003 Jun 25.|
|6||Kropp B, Dabagia M. Scott JW, Lingeman JE. Percutaneous nephrolithotomy directly through an angiomyolipoma. Urology 1994 Dec; 44: 915-917.|
|7||Katz DS, Poster RB. Massive renal angiomyolipoma in tuberous sclerosis. Clinical Imaging 1997; 21:200-202.|
|8||Asayama Y, Fukuya T, Honda H, Kaneko K, Kurolwa T, Yoshimitsu K, Irie H, Shinokuma J. Chronic expanding hematoma of the spleen caused by angiomyolipoma in a patient with tuberous sclerosis. Abdominal Imaging 1998; 23: 527-530.|