Pseudoaneurysm formation in angiomyolipoma (AML) is a rare complication of the disease that can be fatal in the case of improper management. Options for diagnosis and treatment depend on how quickly you proceed in management. We present a case of a 46-year-old female with a ruptured pseudoaneurysm in the right renal AML. The rapid diagnosis with color Doppler ultrasound and contrast-enhanced computed tomography, together with the urgent management with selective angioembolization, were very effective. However, the development of an infected perinephric hematoma made subsequent open drainage and concomitant partial nephrectomy a must. We are also presenting a literature review on the condition using three databases and a random search to reflect on the incidence and associations of that condition with different management and experience. Pseudoaneurysm formation in AML occurs more frequently in young females and is mostly associated with the tuberous sclerosis complex. The rupture of the pseudoaneurysm is a serious complication and can occur spontaneously or with minor trauma. The risk of rupture of pseudoaneurysm is unpredictable; however, a large pseudoaneurysm with a large tumor in a female patient should represent an alarming sign of the need for more intensive follow-up. The gold standard in treatment is selective angioembolization after stabilization of the patient’s general condition.

Angiomyolipoma (AML) is the most common mesenchymal renal tumor and is classified as a tumor of perivascular epithelioid cells. Its reported incidence is 0.1–0.22% of the general population and is four times more common in women.[1] It is a benign renal tumor that consists of varying amounts of mature adipose tissue, smooth muscle, and thick-walled vessels.[2] The two main types of renal AML are the sporadic type, which is more common, and the familial type, which is associated with tuberous sclerosis and is less common. Although vascular complications are uncommon, the risk of vascular complication—especially when the lesion is large—is the main indication for the treatment of AML.[3] The most common of these vascular complications is a rupture with intrarenal or perilesional hemorrhage, which could be fatal.[4] Pseudoaneurysm formation is usually noted in AMLs associated with tuberous sclerosis and is rare in the sporadic variety.[5] The diagnosis of a pseudoaneurysm is primarily made by color Doppler ultrasound, which shows the typical to-and-fro flow pattern in the neck that connects the pseudoaneurysm to the injured artery.[3] Although pseudoaneurysm rupture is a rare complication of renal AML, it remains a serious complication with no definite optimal treatment plan. In this case report, we present a case of ruptured pseudoaneurysm in renal AML and its management. In addition, we present the first conclusive literature review combining all the reported cases of the condition in the literature and how they were managed.

A 46-year-old woman presented to the trauma unit after a fall from a height with right flank pain. Upon medical history review, the patient denied any relevant past medical, obstetrical, gynecological, or social history except for previous right flank pain, for which conservative management was recommended. The patient did not have a definite diagnosis at that time. On examination, she had stable vital signs and was fully conscious. She had right loin tenderness with no palpable mass or hematuria. Full laboratory investigations, pelviabdominal ultrasonography, color Doppler ultrasonography, and contrast-enhanced pelviabdominal computed tomography were ordered and revealed that the patient had anemia with a hemoglobin level of 8 mg/dL, a right renal soft tissue mass, and a perinephric hematoma with a pseudoaneurysm of 4 cm in maximum dimensions (Fig. 1). The preliminary diagnosis of unilateral right renal AML with a ruptured pseudoaneurysm was established. The patient received two units of packed red blood cells followed by selective angioembolization. However, after 3 days, the patient developed severe flank pain, loin tenderness, leukocytosis (white blood cell count of 14,000/μL), and high-grade fever (temperature of 103°F). Pelviabdominal ultrasound, together with the patient’s examination findings, confirmed infection of her perinephric hematoma. Accordingly, surgical exploration with evacuation of the infected perinephric hematoma and a partial nephrectomy was performed (Fig. 2). The excised renal tissue was sent for histopathological examination, which confirmed the presumed diagnosis of typical benign renal AML. Additionally, the patient underwent genetic testing for TSC1 and TSC2 mutations, which was negative. Postoperative follow-up was uneventful. The patient’s last follow-up, 6 months after the procedure, showed no evidence of recurrence. The patient consented to the publication of her case.

Figure 1

Coronal and axial sections of the contrast-enhanced computed tomography showing a right renal angiomyolipoma with a ruptured pseudoaneurysm and perinephric collection. (A) Angiomyolipoma, (B) pseudoaneurysm, and (C) perinephric collection.

Figure 1

Coronal and axial sections of the contrast-enhanced computed tomography showing a right renal angiomyolipoma with a ruptured pseudoaneurysm and perinephric collection. (A) Angiomyolipoma, (B) pseudoaneurysm, and (C) perinephric collection.

Close modal
Figure 2

Intraoperative findings after evacuation and partial nephrectomy.

Figure 2

Intraoperative findings after evacuation and partial nephrectomy.

Close modal

Renal AMLs are benign mesenchymal tumors composed of a variable proportion of adipose tissue, spindle and epithelioid smooth muscle cells, and abnormal blood vessels. They are believed to belong to a family of lesions characterized by a proliferation of perivascular epithelioid cells.[6,7] AML vessels have poor elastic layers and are prone to microaneurysm formation and spontaneous bleeding. The severity of these hemorrhagic events is variable and ranges from spontaneously resolving bleeding to life-threatening hypovolemic shock.[8] Updates in endovascular radiological techniques and devices made angioembolization a major therapeutic option before surgery in many renal vascular and neoplastic diseases, especially in emergencies.

A review of the literature on similar cases in three databases (PubMed, Scopus, and Web of Science) with keywords (angiomyolipoma, pseudoaneurysm, or false aneurysm), together with a random Google search through June 2024 was performed. The PRISMA flow diagram below shows the method of selection (Fig. 3). The results are shown in Table 1.

Figure 3

PRISMA flow diagram of the included and excluded manuscripts.

Figure 3

PRISMA flow diagram of the included and excluded manuscripts.

Close modal
Table 1

Similar cases of pseudoaneurysmal rupture in renal angiomyolipoma identified in the literature

Similar cases of pseudoaneurysmal rupture in renal angiomyolipoma identified in the literature
Similar cases of pseudoaneurysmal rupture in renal angiomyolipoma identified in the literature

As we see in Table 1, the total number of cases is 19. Of these cases, 16 are women, and only three are men, denoting the increased incidence of AML in women.[9] The mean age among the cases is 37.1 years old, representing the common age for presentation of the condition (middle age). We attribute the variation in the age of presentation of the cases to multiple factors, such as the size of the tumor and the presence of an emergency that evokes the alarm.

According to comorbidities, out of 19 cases, nine patients had tuberous sclerosis, identifying the association between the conditions. Pelizzo et al.[10] reported that AML occurs in 80% of tuberous sclerosis patients without commenting on the incidence of pseudoaneurysm formation in these cases. In most cases, a rupture in the pseudoaneurysm occurs spontaneously or because of trivial trauma. In our case, the rupture was posttraumatic, and one case out of the 19 cases identified in the literature review was secondary to trauma.[11]

The classic clinical triad of renal AML is flank pain, palpable tender mass, and hematuria due to intracapsular or retroperitoneal bleeding.[12] In our case and 15 out of the 19 cases we identified in the literature review, the presenting symptom was pain, while 4 cases presented with both hematuria and pain. AMLs tend to bleed because of their hypervascularity and the presence of small aneurysms, which may lead to life-threatening complications.[13] Our case was stable except for anemia. In the literature review, 5 out of the 19 reported cases were stable with a low hematocrit level. We suppose that stability depends on multiple factors, such as severity of bleeding, baseline cardiovascular status, size of the pseudoaneurysm, and speed of stabilizing measures.

Our case had right renal AML, whereas ten of the 19 reported cases in literature also had right renal AMLs, six had left renal AMLs, and three had bilateral renal AMLs. No specific predilection for the side of the tumor was described in the literature except that multiple bilateral renal AML is an indication to investigate for tuberous sclerosis but not the reverse.[14]

Regarding tumor size, the mean size among the mentioned cases was 11.5 cm in maximum dimensions. The larger the tumor size, the higher the risk of rupture.[15] However, the classic cut-off margin for intervention of 4 cm[16] is currently widely disputed.[17,18]

Renal artery angioembolization to proximally or distally occlude renal vessels has low morbidity and, when used to selectively occlude distal vessels, has a low impact on renal function compared to surgical procedures. Selective angioembolization is a very effective intervention to prevent recurrent bleeding and to avoid surgery. The critical component of case management is patient stabilization and prompt angioembolization. By including our case, we present 20 cases, 9 of which were successfully treated by angioembolization without requiring further management. The other cases required radical or partial nephrectomy or post-angioembolization surgery. Preoperative angioembolization facilitates surgical management in the case of large tumors.[19]

Post-pseudoaneurysmal-rupture complications, such as perinephric collection, spontaneously subsided in all cases with conservative management. This is with the exception of one case in which the collection became infected, and drainage was prompted, in addition to our case.

Although we performed the first large literature review encompassing all available literature regarding management of pseudoaneurysm rupture in renal AML, all the retrieved publications are case reports. Accordingly, we encourage future clinical trials on the topic.

Pseudoaneurysm formation in AML occurs more in young females and is mostly associated with the tuberous sclerosis complex. Rupture of the pseudoaneurysm is a serious complication, and it can occur spontaneously or with trauma. Up until this point, there are no reliable methods to predict the risk of pseudoaneurysmal rupture. A large size tumor in a female patient gives us alarm for more strict observation. The gold standard in treatment is selective angioembolization after stabilization of the patient’s general condition. However, the presence of large perinephric hematoma after rupture can complicate management and can even mandate more intensive management.

1.
Al Omran
B,
Ansari
N.
Aneurysm in a large sporadic renal angiomyolipoma
.
Oman Med J
.
2016
;
31
:
223
236
.
2.
Jinzaki
M,
Tanimoto
A,
Narimatsu
Y,
et al
Angiomyolipoma: imaging findings in lesions with minimal fat
.
Radiology
.
1997
;
205
:
497
502
.
3.
Lapeyre
M,
Correas
JM,
Ortonne
N,
et al
Color-flow Doppler sonography of pseudoaneurysms in patients with bleeding renal angiomyolipoma
.
AJR Am J Roentgenol
.
2002
;
179
:
145
147
.
4.
Parashari
UC,
Khanduri
S,
Bhadury
S,
Singh
G.
Multi-detector computed tomography angiography of a ruptured giant renal angiomyolipoma with pseudoaneurysm and associated saccular dilatation of left renal artery
.
Urol J
.
2013
;
10
:
1147
1150
.
5.
Patil
AR,
Chandra
R,
Gupta
A,
Thukral
BB.
Giant aneurysm formation in sporadic renal angiomyolipoma
.
J Radiol Case Rep
.
2010
;
4
:
21
27
.
6.
Nelson
CP,
Sanda
MG.
Contemporary diagnosis and management of renal angiomyolipoma
.
J Urol
.
2002
;
168
(
Part 1
):
1315
1325
.
7.
Jinzaki
M,
Silverman
SG,
Akita
H,
et al
Renal angiomyolipoma: a radiological classification and update on recent developments in diagnosis and management
.
Abdom Imaging
.
2014
;
39
:
588
604
.
8.
Acar
T,
Harman
M,
Sen
S,
et al
Angiomyolipoma with epithelial cyst (AMLEC): A rare variant of fat poor angiomyolipoma mimicking malignant cystic mass on MR imaging
.
Diagn Interv Imaging
.
2015
;
96
:
1195
1198
.
9.
Fujii
Y,
Ajima
J,
Oka
K,
et al
Benign renal tumors detected among healthy adults by abdominal ultrasonography
.
Eur Urol
.
1995
;
27
:
124
127
.
10.
Pelizzo
G,
Vallone
MG,
Milazzo
M
, et al
Renal angiomyolipomatosis and bleeding aneurysms in a tuberous sclerosis context: selective artery embolization in a girl with end-stage renal failure
.
Pediatr Rep
.
2020
;
12
:
8352
.
11.
Thapa
N,
Maharjan
S,
Hona
A,
et al
Spontaneous rupture of renal angiomyolipoma and its management: a case report
.
Ann Med Surg (Lond)
.
2022
;
79
:
104037
.
12.
Idilman
IS,
Vesnic
S,
Cil
B,
Peynircioglu
B.
Giant renal artery pseudoaneurysm caused by rupture of renal angiomyolipoma following pregnancy: endovascular treatment and review of the literature
.
Saudi J Kidney Dis Transpl
.
2014
;
25
:
385
389
.
13.
Jenil
AA,
Sathesan
B,
Sivasethambaram
K,
et al
Endovascular embolization of ruptured giant pseudoaneurysm of renal angiomyolipoma in a patient with tuberous sclerosis
.
Ceylon Med J
.
2019
;
64
:
118
120
.
14.
Shankar
S,
Hulikanthimatt
KS,
Awatti
SM,
Narayanrao
ST.
Bilateral multifocal renal angiomyolipoma associated with Wunderlich’s syndrome in a tuberous sclerosis patient
.
J Clin Diagn Res
.
2015
;
9
:
ED01
ED03
.
15.
Zeid
M,
Sayedin
H,
Nabi
N,
et al
Active surveillance for renal angiomyolipoma less than 4 centimeters: a systematic review of cohort studies
.
Cureus
.
2022
;
14
:
e22678
.
16.
Oesterling
JE,
Fishman
EK,
Goldman
SM,
Marshall
FF.
The management of renal angiomyolipoma
.
J Urol
.
1986
;
135
:
1121
1124
.
17.
Vos
N,
Oyen
R.
Renal angiomyolipoma: the good, the bad, and the ugly
.
J Belg Soc Radiol
.
2018
;
102
:
41
.
18.
Ouzaid
I,
Autorino
R,
Fatica
R,
Herts
BR,
McLennan
G,
Remer
EM,
et al
Active surveillance for renal angiomyolipoma: outcomes and factors predictive of delayed intervention
.
BJU Int
.
2014
;
114
:
412
417
.
19.
Mignon
F,
Dufour
C,
Boidard
F.
Preoperative selective embolization of a renal angiomyolipoma allowing conservative surgery
.
Prog Urol
.
2006
;
16
:
78
81
.
20.
Adler
J,
Greweldinger
J,
Litzky
G.
“Macro” aneurysm in renal angiomyolipoma: two cases, with therapeutic embolization in one patient
.
Urol Radiol
.
1984
;
6
:
201
203
.
21.
Martínez Barcina
MJ,
Quintian Schwieters
C,
et al
Pseudoaneurisma intratumoral: manifestación radiológica atípica del sangrado de un angiomiolipoma
.
Radiología
.
2008
;
50
:
79
81
.
22.
Barghi
MR,
Rahmani
MR,
Haghighatkhah
HR,
et al
Management of intratumoral pseudoaneurysm in a patient with bleeding renal angiomyolipoma
.
Indian J Urology
.
2006
;
22
:
75
76
.
23.
Bogue
CO,
Hodnett
P,
Doyle
DJ,
et al
Answer to case of the month #137. Giant pseudoaneurysm complicating an angiomyolipoma in a patient with tuberous sclerosis
.
Can Assoc Radiol J
.
2008
;
59
:
213
216
.
24.
Chong
J,
Zhang
J,
Ning
C,
et al
Fat-poor renal angiomyolipoma combined with pseudoaneurysm: a case report
.
Ann Palliat Med
.
2021
;
10
:
2343
2348
.
25.
Othman
AE,
Syha
R,
Ketelsen
D.
Schnell progredientes, rupturiertes pseudoaneurysma eines renalen angiomyolipoms bei einer patientin mit tuberöser sklerose [Article in German
].
Rofo
.
2016
;
188
:
1072
1074
.
26.
Leite
T,
Pazinato
LV,
Vidal
MJA,
et al
Endovascular treatment of intrarenal aneurysms bleeding and angiomyolipomas in a patient with tuberous sclerosis and polycystic kidney disease
.
J Bras Nefrol
.
2023
;
45
:
111
115
.
27.
Magabe
P,
Otele
W,
Mugambi
L.
Large aneurysm in renal angiomyolipoma causing life-threatening retroperitoneal hemorrhage
.
African J Urology
.
2014
;
20
:
193
196
.
28.
Corso
R,
Carrafiello
G,
Rampoldi
A,
et al
Pseudoaneurysm after spontaneous rupture of renal angiomyolipoma in tuberous sclerosis: successful treatment with percutaneous thrombin injection
.
Cardiovasc Intervent Radiol
.
2005
;
28
:
262
264
.
29.
Malik
MA,
Tharek
A,
Kairuddin
FF,
et al
Spontaneous rupture of an intratumoral pseudoaneurysm in a giant renal angiomyolipoma
.
Interventionalist J
.
2022
;
2
:
1
5
.
30.
Meher
R,
Lynser
D,
Handique
A,
et al
Spontaneous giant pseudoaneurysm in a renal angiomyolipoma associated with tuberous sclerosis complex
.
Clin Case Rep
.
2016
.

Competing Interests

Sources of support: None. Conflicts of interest: None.

This work is published under a CC-BY-NC-ND 4.0 International License.