Article Type : Case Report
Authors : El Hak HS, Hèla BJ , Mahdi BD, Majdi G, Arwa Z, Riadh M, Aiman D and Imed F
Keywords : Nephroblastoma; Renal vein; Inferior vena cava; Tumoral thrombus; Surgery; Cavotomy
Nephroblastoma is one of
the most common renal pediatric solid tumors. It has a strong tendency of
extension of the tumor thrombus along to the renal vein, the inferior vena
cava, and the right atrium. We report the case of a 02 years and 08
months-year-old child, who received 8 chemotherapy doses for a left kidney
nephroblastoma invading the left renal vein and inferior vena cava. Two months
later, the tumor size decreased and measured 13 X 10 cm but the vascular
thrombus persisted. So, he underwent left nephrectomy and the removal of the
intravascular tumoral thrombus under median laparotomy and cavotomy. The
postoperative CT scan showed a small hematoma and a thrombosis of the
infrarenal vena cava. So, we decided to continue curative anticoagulant therapy
for 3 months. Surgical management of nephroblastoma with vascular extension
remains a significant challenge. Intravascular extension must be well
characterized in all patients in order to indicate preoperative chemotherapy
and guide resection approach.
Nephroblastoma, also known as Wilms tumor, is one of
the most common renal pediatric solid tumors. It has an incidence estimated at
6% of pediatric tumors, it accounts for more than 90% of all childhood kidney
tumors (1). It has a strong tendency to invade nearby vessels in the form of a
thrombus. In fact, extension of tumor thrombus along to the renal vein into the
inferior vena cava occurs in 4-10% of all patients. Tumor thrombus extending to
the right atrium is less reported as 0.7-1 Intravascular thrombus occurs in
20–35% of patients, while extension to the IVC ranges from 4 to10% [1,2]. A
thrombus reaching the atrium is a more rare event and occurs in less than 1% of
all patients [3].
Treatment consists especially on preoperative
chemotherapy and surgical excision, and needs multidisciplinary care involving
oncologists, pediatric surgeons, and vascular surgeons [4]. We report the case
of a 02 years and 08 month-year-old child, who was treated for a left kidney
nephroblastoma invading the left renal vein and inferior vena cava, who underwent
surgery to remove the left kidney and the intravascular tumoral thrombus.
A 02 years and 08 months year-old child, was followed
by pediatrics and oncologists for left kidney nephroblastome. The first CT scan
showed a tumoral mass measuring 16 X 9.5 cm that was invading the left renal
vein and the inferior vena cava (Figures 1 and 2).
The patient has then received 8 chemotherapy doses in
order to reduce the tumor size and the extent of the vascular thrombus, but the
initial CT scan showed an increase in tumor size and a persistence of left
renal vein and IVC thrombus.
Two months later, the tumor size decreased and measured 13 X 10 cm but the vascular thrombus persisted. So, we decided to operate the patient. Surgery was performed under general anesthesia. Via a median laparotomy, we accessed the retroperitoneum. The renal tumor was large, and adherent to the diaphragm and the left colic flexure. After liberating the adhesions and controlling the left kidney, the renal artery and vein and then the ureter, we proceeded to a total nephrectomy (Figure 3).
Figure 1: Preoperative CT scan showing the left renal nephroblastoma (arrow).
Figure 2: vascular extension in
the left renal vein and inferior vena cava.
The second step of the procedure consisted on
controlling the infrarenal and suprarenal segments of the inferior vena cava.
After heparinization, the vena cava was clamped and via a covotomy we extracted
the tumoral thrombus (Figure 4).
The last step of the surgery was to perform lymph
nodes clearance and then closing of the median laparotomy. The patient was
extubated after one day, and was put under curative heparin dose. The control
CT scan showed a small hematoma and a thrombosis of the infrarenal vena cava
(Figure 5), without clinical symptoms of deep venous thrombosis. So, we decided
to continue curative anticoagulant drugs for 3 months.
Figure 3: Surgical control of the
tumoral left kidney.
Figure 4: Extraction of the
thrombus from the inferior vena cava.
Nephroblastoma is the most common abdominal pediatric
tumor. It is a malignant embryonic tumor that develops from the mesoderm of the
intermediate cell mass before differentiation. It typically presents between
ages 3 to 5 years but can also be seen in new born infants [5].
Clinical presentation is usually made of an asymptomatic abdominal mass in the
majority of children. However, abdominal pain, hematuria, urinary tract
infections, varicocele and hypertension or hypotension can be seen. The
most common initial presenting symptom is abdominal pain (30% to 40%) followed
by high blood pressure (25%), and hematuria (12% to 25%) [6].
Treatment of Wilms tumor without vascular involvement
is nephrectomy in majority of cases followed by chemotherapy. There are other
protocols that start with chemotherapy first and perform the nephrectomy later.
Lymph nodes clearance is very important for staging and to improve general
survival [6]. Intravascular extension into renal vein then the vena cava occurs
in only 4-10% of patients. It is reported that intravascular extension when
Wilms’ tumor is located in the right kidney is more common due to the shorter
renal vein. It is also reported that vascular involvement is more frequent in
older children with a mean age of 3.75 years than younger children [7].
Several classifications for vascular extension were established in the past. Daum’s classification that was established in 1994 [8] was the most used classification until 2013, when Abdullah et al [9] proposed a modification of Daum’s classification and suggested the addition of a fifth stage for intraventricular extension of the vascular thrombus. The importance of this stage is mainly in anesthetic management. Positive pressure ventilation may cause tricuspid valve immediate cardiac arrest [7].
Figure 5: control CT scan showing
the presence of a small hematoma and a thrombosis of the inferior vena cava.
The
operative approach of Wilms’ tumor with intravascular extension represents a
constant challenge, and the surgeons should have an appropriate experience
level. Extension below the hepatic veins can be approached via a laparotomy. However,
proximal extension above the hepatic veins requires the same incision extended
to median sternotomy [7]. The post-operative outcomes are influenced by
intravascular extension [10-12], with an odds ratio of 2.2 for complications
when intravascular thrombus is present. There was also an association between
decrease in surgical complication’s rate and the administration of neoadjuvant
chemotherapy [13]. It’s interesting to know that survival rates do not differ
from those with uncomplicated Wilms’ tumor [14].
The prognosis depends on the tumor stage and
histology. Favourable histology has a better survival rates, it’s estimated at
86% to 99%, while unfavorable histology survival varies from 38% to 84%
depending on the stage [15-18]. Recurrence risk is estimated at 15%, it’s
mainly found within the first 2 years after surgery [6].
Surgical management of Wilms’ tumor with vascular
extension remains a significant challenge. Intravascular extension must be well
characterized in all patients in order to indicate preoperative chemotherapy
and guide resection approach. The surgical team should be multidisciplinary
involving pediatric and vascular surgeons and should have an appropriate
experience level.