CASE 9478 Published on 21.07.2011

Remember angiomyolipoma in polycystic kidneys of patient with tuberous sclerosis

Section

Uroradiology & genital male imaging

Case Type

Clinical Cases

Authors

Emily Daulton, Aniket Despande, Bernard Wee, John Parkin, Vincent Koo

62 Wentworth Way B32 2UX;
Email:b_wee@hotmail.com
Patient

42 years, female

Categories
Area of Interest Kidney ; Imaging Technique CT, Catheter arteriography, Fluoroscopy
Clinical History
A female nursing home resident with tuberous sclerosis, epilepsy and learning difficulty, was admitted with recent onset of breathlessness and anaemia (haemoglobin level of 4.1g/dl). Previous CT report dated 2007 raised a diagnosis of bilateral polycystic kidney. Clinically, she was pyrexic, hypotensive and had a palpable tender right flank mass.
Imaging Findings
CT showed grossly enlarged kidneys with abnormal morphology and tissue attenuation characteristics. The right kidney measured 27cm x 15cm, with the report suggesting a large 10x12x11cm cyst with haemorrhage (Fig. 1). On review, these features were consistent with an acute haemorrhage of angiomyolipoma. She continued to become haemodynamically unstable despite repeated blood transfusion. Emergency surgery was deemed to be very high risk for mortality because of her significant comorbidities and hence she proceeded for vascular embolisation to stop the haemorrhage. Selective embolisation of the aneurysms and abnormal vascular territory was performed with coils (Fig. 2). A total of 22 coils (MReye coils, Cook, USA) of various sizes (3mm - 15mm diameter) were utilised. Post-procedure angiograms demonstrated excellent outcome with obliteration of abnormal regions (Fig. 3). The procedure was successful at controlling the haemorrhage. Repeat CT (Fig. 4) 3 days later showed underlying ischaemic necrosis following embolisation.
Discussion
Angiomyolipomas (AML) are usually benign neoplasms consisting of varying amounts of mature adipose tissue, smooth muscle and thick walled vessels affecting the brain, kidneys, heart, eyes and skin. About 20% are associated with tuberous sclerosis (TS), and nearly 50% of TS patients will develop AMLs. TS is an autosomal dominant condition, comprising mental retardation, epilepsy and adenoma sebaceum [1]. TS patients with intracerebral benign neoplasm result in neurological dysfunctions and learning difficulties. AML in TS is more likely to be bilateral and multicentric, with higher growth rates and increase in symptomatic presentation [2].
The definitive investigation is to proceed to an abdominal CT, which will reveal a lesion with varying degrees of fat within, defined as Hounsfield units of less than -20. This is diagnostic of AML [3]. Another key finding is the lack of calcification within the lesion – if identified, then the working diagnosis is RCC.
Oesterling et al have proposed that the management of AML should be based on size and symptoms. For lesions less that 4cm diameter, these should have conservative management with yearly CTs and 6 monthly for those larger than 4cm, or with TS associated AML. If size or symptomatic lesion increases, these should be managed with arterial embolisation; and anyone with TS-associated AML, should be embolised when greater than 4cm, due to the higher risk of haemorrhage [4]. The complication rate is low, with the most common side effect being post-embolisation syndrome. It has an incidence of 40-63.6% and is secondary to inflammatory mediators released by the infarcted tissue. It comprises of fever, nausea, vomiting and loin pain. These symptoms are thought to be proportional to the amount of ischaemic tissue mass, and are therefore reduced by highly selective embolisation [5,6]. Other complications include infection and abscess formation, pleural effusion, renal insufficiency and continued haemorrhage [7].
In our case, the patient was not suitable for surgery due to significant co-morbidities and the sheer size of the lesion which would render surgery technically difficult. Hence selective embolisation was the most appropriate therapy for the patient, as it enables preservation of normal renal parenchyma. The literature show that it is only the TS associated AMLs that re-grow or indeed recur: about 43% recurred in one study, and all patient required re-embolisation [3,7,8]. Although there are no current recommendation for post procedure follow up, it has been suggested that follow up CT, especially in TS patients, is prudent.
Differential Diagnosis List
Bleeding angiomyolipoma
Renal cell carcinoma
Retroperitoneal liposarcoma
Final Diagnosis
Bleeding angiomyolipoma
Case information
URL: https://www.eurorad.org/case/9478
DOI: 10.1594/EURORAD/CASE.9478
ISSN: 1563-4086