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 Table of Contents  
CASE REPORT
Year : 2020  |  Volume : 26  |  Issue : 2  |  Page : 222-224

Huge extrarenal retroperitoneal angiomyolipoma complicating pregnancy


1 Department of General Surgery, Aster Malabar Institute of Medical Sciences, Kozhikode, Kerala, India
2 Department of Oncosurgery, Aster Malabar Institute of Medical Sciences, Kozhikode, Kerala, India
3 Department of Obstetrics and Gynecology, Aster Malabar Institute of Medical Sciences, Kozhikode, Kerala, India
4 Department of Pathology, Aster Malabar Institute of Medical Sciences, Kozhikode, Kerala, India

Date of Submission29-Jul-2020
Date of Decision13-Aug-2020
Date of Acceptance14-Oct-2020
Date of Web Publication07-Nov-2020

Correspondence Address:
Dr. Amal George
Department of General Surgery, Aster Malabar Institute of Medical Sciences, Govindapuram P.O, Kozhikode - 673 016, Kerala
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ksj.ksj_2_20

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  Abstract 


Retroperitoneal extrarenal angiomyolipoma (AML) presents a diagnostic challenge, because it can mimic other malignant and benign retroperitoneal tumours. Oestrogen and progesterone receptor expression is frequent in AML, so hormonal changes during pregnancy act as fertile soil for attaining huge size. During pregnancy, AMLs have high inclination to enhance in size and break. This increased risk is due to presence of progesterone and oestrogen receptors in AMLs, an enhanced maternal circulation and potentially greater intra-abdominal pressure related with pregnancy. We are presenting a 38-year-old pregnant patient with retroperitoneal extra renal AML, which presented as incidentally detected huge retroperitoneal mass.

Keywords: Angiomyolipoma, extrarenal, retroperitoneal


How to cite this article:
George A, Thottiyen S, Akshay Viswanath U V, Salim V P, Thomas JA, Beegaum O R, Shameem S, Basheer S. Huge extrarenal retroperitoneal angiomyolipoma complicating pregnancy. Kerala Surg J 2020;26:222-4

How to cite this URL:
George A, Thottiyen S, Akshay Viswanath U V, Salim V P, Thomas JA, Beegaum O R, Shameem S, Basheer S. Huge extrarenal retroperitoneal angiomyolipoma complicating pregnancy. Kerala Surg J [serial online] 2020 [cited 2020 Nov 30];26:222-4. Available from: http://www.keralasurgj.com/text.asp?2020/26/2/222/300228




  Introduction Top


Angiomyolipomas (AMLs) are uncommon complex mesenchymal neoplasms typically arising within the kidney and are composed of mature adipose tissue, smooth muscle cells and thick-walled blood vessels. Renal AMLs include 1% of renal lesions, with female predisposition. The incidence of AML amongst general population is 0.07%–0.3%.[1] First case of retroperitoneal extra renal AML was reported in 1982 by Friis and Hjortrup. As per literature, amongst 60 cases of extrarenal AML reported, only 16 cases were retroperitoneal extrarenal AML.[2]


  Case Report Top


This 38-year-old otherwise healthy pregnant female with obstetric score G3P2L2 with 32-week gestational age, presented with grossly distended abdomen and back pain. On palpation, there was a large, firm and fixed mass in abdomen, towards left hypochondrium, other than gravid uterus. Ultrasound and Doppler imaging showed intrauterine growth restriction of foetus, Doppler resistant placenta previa with large retroperitoneal tumour. Magnetic resonance imaging (MRI) abdomen reported as large left-sided intra-abdominal retroperitoneal mass of 19 cm × 10 cm × 11 cm extending from the left hypochondriac region to left iliac fossa with mass effect over other intra-abdominal structures, reported as suspicious of low-grade liposarcoma or lipoma [Figure 1]a, [Figure 1]b, [Figure 1]c. There was associated moderate left-sided hydroureteronephrosis and mass effect over other intra-abdominal organs.
Figure 1: (a) Sagittal magnetic resonance T2-weighted image showing large retroperitoneal tumour involving entire abdomen. (b) Transverse magnetic resonance imaging image showing gravid uterus and left sided mass. (c) Coronal magnetic resonance T2 weighted image showing gravid uterus with foetus and huge left-sided mass

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She underwent elective caesarean delivery at 33 weeks' gestational age through midline laparotomy and excision of retroperitoneal mass [Figure 2]a was done through the same incision. Intraoperatively, an incidentally detected nodule was seen over left kidney, which was also excised. Post-operative period was uneventful. Microscopic examination of specimen showed mature adipocytes, spindle moulded smooth muscle cells and many thick walled blood vessels [Figure 2]b. Histopathology both retroperitoneal mass and left renal nodule were reported as AML with Ki 67 proliferation index 3%, HMB 45 as well as Melanin A with focal positivity on immunohistochemical staining [Figure 2]c.
Figure 2: (a) Gross image of specimen showing well defined encapsulated mass. (b) Microscopic image of specimen showing mature adipocytes, spindle moulded smooth muscle cells and many thick-walled blood vessels. (c) Immunohistochemical staining showing HMB 45 positivity

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  Discussion Top


AML is a benign neoplasm of monoclonal origin, sometimes referred as renal hamartoma, perivascular epithelioid cell tumour or choristoma. It has triphasic morphology on histology that includes mature adipose tissue, perivascular spindle cells and thick-walled blood vessels.[3] AMLs can occur sporadically or in association with tuberous sclerosis, which includes 45%–80% of cases.[4] Typical sporadic AML is usually incidental finding, unilateral and asymptomatic. Majority of sporadic AMLs are seen in middle aged women (4th or 5th decade). Tuberous sclerosis associated AML is seen in younger age, bilateral, multiple, less female to male predominance and is usually symptomatic.[4]

Classical presentation of AML includes flank pain, gross haematuria and palpable mass. Massive retroperitoneal haemorrhage (known as Wunderlich syndrome) is the most important complication of AML, noted in up to 10% of patients.[5] The Wunderlich syndrome is clinically characterised by the Lenk's triad constitutive of acute flank pain, hypovolemic shock and a flank mass. AMLs have a benign clinical course, with slow development pattern and deficiency of distant metastasis.

Extrarenal AMLs (ERAML) are rare and usually present as incidentalomas on imaging.[6] These tumours were reported in liver, retroperitoneum, adrenal glands, colon, urinary bladder, hilar lymph nodes, lungs, ribs, oral cavity, nasal cavity, abdominal wall, fallopian tube, uterus and skin [4],[6] Retroperitoneum is the second-most common site for ERAML.[3] Retroperitoneal extrarenal AMLs (RERAML) are usually >10 cm and remain asymptomatic in view of their retroperitoneal location.[4] However, they can less commonly present with non-specific symptoms such as vague abdominal pain, fullness in epigastric region/abdomen, haematuria, weight gain and constipation, and rarely with enlarged abdomen or ureteric obstruction or retroperitoneal haemorrhage.[7]

There is increased risk of spontaneous rupture during pregnancy. The main leading factors for spontaneous rupture during pregnancy are increased growth rate and blood volume. During pregnancy, there is increased pelvic vascularity, this along with oestrogen progesterone receptors in AML lead to huge size of tumour during pregnancy. This large tumour along with gravid uterus may lead to aortic compression which complicates foetal growth and also increases maternal morbidity by aggravating compressive effects over adjacent structures.

Although most of these RERAML have been benign, it is difficult to exclude malignancy which is the closest differential diagnosis due to similarities in imaging appearance, and the common differentials include lipoma, liposarcoma, adrenal myelolipoma and papillary renal cell carcinoma (RCC)[6],[7] The most common differential is liposarcoma, which is difficult to differentiate from RERAML even on imaging and histopathological examination. Computed tomography and MRI help in the diagnostic dilemma by the following: RERAML grow from perinephric fat whereas liposarcomas arise from exterior the Gerota's fascia; features favouring RERAML include history of AML, heterogeneity on imaging, haemorrhage, absence of calcifications, microscopic fat, non-enhanced computed tomography hyperdensity, T2 low-signal intensity and dilated intratumoral vessels. On immunohistochemical staining HMB-45 positivity of RERAML and positive fluorescence in situ hybridisation test for MDM2 amplification in liposarcomas can help in differentiation.[6],[7] The differentiation of RCC and RERAML can be made by the presence of calcifications, enhancing intratumoral nodules and invasion into renal vein or inferior vena cava being more common in the former than the latter.

Treatment options include minimally invasive techniques such as radiofrequency ablation, microwave ablation, cryoablation, selective angioembolisation (SAE) and surgery; however, the latter two have proven to be the most effective for symptomatic AML.[8] SAE is usually indicated for patients with active bleeding, large retroperitoneal haemorrhage, plan for subsequent staged surgical resection, or large tumours with the advantage of short recovery period and preserved renal function.[6]


  Conclusion Top


Huge retroperitoneal mass during pregnancy can lead to morbidity and mortality of both the foetus and the mother. Hence, in the case of incidentally detected retroperitoneal mass during gestation, AML should be kept as a differential in mind. Careful timely evaluation and elective caesarean delivery and excision of tumour will lead to favourable outcome of mother and child.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Obara W, Sato K, Owari Y, Nozawa T, Isurugi K, Ohmori S, et al. Perinephric angiomyolipoma: A unique development pattern surrounding the kidney. Int J Urol 2005;12:305-7.  Back to cited text no. 1
    
2.
Minja EJ, Pellerin M, Saviano N, Chamberlain RS. Retroperitoneal extrarenal angiomyolipomas: An evidence-based approach to a rare clinical entity. Case Rep Nephrol 2012;2012:374107.  Back to cited text no. 2
    
3.
Jawahar A, Kazan-Tannus J. Retroperitoneal extrarenal angiomyolipoma at the surgical bed 8 years after a renal angiomyolipoma nephrectomy: A case report and review of literature. Urol Ann 2017;9:288-92.  Back to cited text no. 3
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4.
Kori C, Akhtar N, Vamsidhar PN, Gupta S, Kumar V. Giant exophytic renal angiomyolipoma mimicking as retroperitoneal sarcoma; a case report with review of literature. J Clin Diagn Res 2015;9:XJ01-2.  Back to cited text no. 4
    
5.
Channabasappa Kori NA, Vamsidhar PN, Gupta S, Kumar V. Giant exophytic renal angiomyolipoma mimicking as retroperitoneal sarcoma; a case report with review of literature. J Clin Diagn Res 2015;9:XJ01.  Back to cited text no. 5
    
6.
Minja EJ, Pellerin M, Saviano N, Chamberlain RS. Retroperitoneal extrarenal angiomyolipomas: An evidence-based approach to a rare clinical entity. Case Rep Nephrol 2012;2012:374107.  Back to cited text no. 6
    
7.
Vîlcea ID, Victor R, Mirea CS, Simionescu CE, Mogoantă SŞ, Moraru E, et al. Extrarenal retroperitoneal angiomyolipoma with unusual evolution. Rom J Morphol Embryol 2015;56:263-6.  Back to cited text no. 7
    
8.
Lee YC, Huang SP, Liu CC, Wu WJ, Chou YH, Huang CH. Giant extrarenal retroperitoneal angiomyolipoma: A case report and literature review. Kaohsiung J Med Sci 2003;19:579-82.  Back to cited text no. 8
    


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