Article Type : Case Report
Authors : Mousa M, Alzate D, Bisht R, Towbin R and Aria D
Keywords : Angiomyolipoma; Pediatric Tuberous Sclerosis
We present a case in which a coil embolization was used to
treat an active hemorrhage from an angiomyolipoma in a pediatric patient.
Angiomyolipomas most commonly occur in patients with tuberous sclerosis and
often bleed once the tumor is larger than 4 cm. Traditional treatments such as
partial or complete nephrectomies can result in significant complications. An
arterial embolization was performed to target the hemorrhagic tumor.
A 16-year-old female presented to an outside
institution with syncope, right upper quadrant abdominal pain, and pallor. Past
medical history was significant for tuberous sclerosis, developmental delay,
and hepatic cavernous malformation. Physical exam demonstrated ash leaf patches
over the torso. Laboratory findings revealed a haemoglobin level of 9.6 g/dL
while a CT abdomen/pelvis demonstrated an acute, large, intra-abdominal
haemorrhage. The patient was transferred to our emergency department and active
bleeding was confirmed with a repeat haemoglobin of 6.6 g/dL. Vitals signs were
stable but significant for tachypnea with a respiratory rate of 40 breaths/min,
tachycardia with a heart rate of 109 bpm, and normotensive with a blood
pressure of 129/98 mmHg. The patient was transfused pRBCs while interventional
radiology was consulted for embolization.
Figure 1: Contrast-enhanced CT abdomen/pelvis.
Axial, Sagittal, and Coronal images demonstrate multiple bilateral renal masses demonstrating fat-attenuation, consistent with angiomyolipomas. There is a large right prerenal hematoma displacing the kidney anteriorly with active contrast extravasation (black arrow) along the posteromedial aspect of the right upper pole (Figure 1).
Figure 2: Right renal angiography.
Active haemorrhage secondary to angiomyolipoma in
patient with tuberous sclerosis.
Renal angiomyolipoma (AML) is a benign mesenchymal
soft tissue tumour that arises in the cortex or medulla of the kidney. AML is
considered “triphasic” in that it consists of adipose tissue, blood vessels,
and smooth muscle [1]. AML can arise sporadically or through an inherited
disorder. AML most commonly arises due to tuberous sclerosis compared to
sporadic [2]. The most dominant type of AML present in tuberous sclerosis is of
epithelioid origin.
Histologic fat
composition of the tumour allows a diagnosis of AML to be made readily by
abdominal CT or MRI [3]. Most sporadic AMLs are found incidentally, however in
a patient with tuberous sclerosis, a CT scan is ordered to look for potential
renal AMLs. AMLs may contain macroscopic or microscopic fat. In order to
distinguish between the two, an MRI may be ordered to assess for
fat-suppression. Due to their vascular nature, AMLs are prone to aneurysm
formation and rupture. Complications such as haemorrhage can result in a
symptomatic drop in haemoglobin and anaemia. Up to one-third of patients can
present with hypovolemic shock [4]. Symptomatic AMLs can present with Lenk’s
triad, which consists of flank pain, abdominal tenderness and internal
bleeding. Bleeding typically occurs when tumours are greater than 4 cm.
Patients are typically asymptomatic when tumours are less than 4 cm [5,6].
Traditional treatments of AML included nephrectomies or partial nephrectomies.
However, these therapeutic options are associated with significant
complications and risks [7]. Today, the preferential therapy is angiography
with selective arterial embolization [8].
Renal angiomyolipomas are commonly seen in patients
with tuberous sclerosis. Despite their multiplicity, they rarely are prone to
aneurysm formation or rupture when less than 4 cm. Small lesions can therefore
be closely monitored via imaging. AMLs larger than 4 cm have greater propensity
for acute bleeding and are therefore amenable to angiography and embolization
as opposed to traditional surgical therapeutic options even when asymptomatic.
When symptomatic, acute arterial bleeding commonly requires urgent intervention.