AVFs or acquired renal AVMs are relatively rare lesions that were first described by Varela in 1928 [
5]. Renal AVF usually results from trauma, biopsy, surgery, or inflammation, and the presentations of renal AVF include hematuria, hypertension, left ventricular hypertrophy, cardiac failure, abdominal pain, and flank pain [
2,
6]. However, no relevant medical history or hematuria is observed in this case, although hematuria is the most common symptom of patients with renal AVF [
7]. Therefore, this individual is considered an atypical case of congenital renal AVM with no hematuria. Varicocele is the primary presentation of our case. Several reported cases showed right-sided varicocele as a presentation of right renal tumor [
8,
9]. An acute nontraumatic varicocele, especially on the left side, may also indicate the presence of a retroperitoneal mass [
10]. In a case with varicocele, the symptom recurred after subinguinal varicocelectomy, and RCC was definitely diagnosed by histology after a radical nephrectomy [
11]. However, varicocele is a rare symptom of RCC with inferior vena cava tumor thrombus, although ultrasound and CT could make the diagnosis of retroperitoneal or renal tumor in most cases [
12]. Cirsoid renal AVM may be misdiagnosed as renal tumor [
13,
14] or renal pelvis tumor [
1] due to its remarkable similarity with renal tumor in radiological presentation. CT findings of renal AVM are commonly characterized by masses of renal sinus vascular density, which surround the pelvicaliceal system [
15]. It might be very difficult to confirm the diagnosis when irregular masses in the renal parenchyma are shown by CT. A low density area in contrast-enhanced CT was suspected to indicate ischemic renal parenchyma due to the steal phenomenon of renal AVM [
14]. The patient in our study presented with varicocele and renal mass, which further complicated the case. MRI may help to differentiate renal AVM from renal tumor. However, if imaged during a delayed phase after gadolinium administration, it may be difficult to differentiate an AVM from an enhancing solid renal sinus mass [
16]. In this case, MRI showed a tangle of enlarged vessels and early draining vein in his left kidney, which was consistent with renal AVM [
16].
Angiographic embolization (AE) is being used with increasing frequency due to minimal invasion, fewer complications, and preservation of the renal function [
18]. Clinically, observation is the main treatment of renal AVM in asymptomatic cases. Embolization, partial nephrectomy, and selective arterial ligation are also choices for those cases with a variety of symptoms [
19,
20]. In our case, selective embolization according to previously described criteria [
21] preserved most of the renal parenchyma instead of nephrectomy. Our patient has been followed up for 26 months and the regression of varicocele was observed at 6 months postoperation, and no sign of relapse of the AVM was observed.