Interventional radiologyCase Type
Candita Gianvito1, Scandiffio Rossella1, Cioni Roberto1, Caramella Davide1, Crocetti Laura1Patient
42 years, female
A 42-year-old woman with known lymphangioleiomyomatosis (LAM) and renal benign tumours accessed our Emergency Department complaining of a two-week history of continuous left flank pain.
Unenhanced chest and upper abdominal CT scan showed the stability of LAM-associated small thin-walled cysts in the lungs (Fig. 1) and detected multiple bilateral inhomogeneous renal lesions (Fig. 2). The largest lesion (15x10x9 cm) was localized in the left kidney with hypodense fatty areas and hyperdense hemorrhagic areas, without signs of current extravasation. Enhanced upper abdominal CT scan (Figure 3) demonstrated the presence of pseudoaneurysms within the lesion.
The CT findings allowed to reach the diagnosis of hemorrhagic angiomyolipoma (AML) of the left kidney.
A transcatheter selective arterial embolization (SAE) was performed to treat the renal lesion with a recent history of bleeding, avoiding radical nephrectomy. Once a super-selective catheterisation of AML feeding vessels was achieved (Fig. 4), 700-900 µm Embosphere® microspheres were injected and IDCTM-18 coils were released in order to assure the occlusion of the hypertrophic capsular arteries. A control selective arteriography (Fig. 5) showed devascularization of almost 90% of the lesion, with a rate of residual renal parenchyma of 30%.
LAM is a rare disease characterized by proliferation of neoplastic pulmonary interstitial smooth cells (LAM cells), resulting in a cystic pneumopathy and recurrent pneumothorax. [1,2] The disease almost exclusively affects women of childbearing age. LAM may occur sporadically but is commonly associated with tuberous sclerosis complex (TSC-LAM). 
LAM usually presents with obstructive dyspnoea and pneumothorax.  Approximately half of patients with sporadic LAM and nearly all ones with TSC-LAM are affected by AMLs, usually of the kidney. When haemorrhagic complication of AML occurs, the associated clinical signs are hematuria, palpable mass and symptoms of retroperitoneal haemorrhage such as flank pain or shock. 
On abdominal CT or MRI, AML usually shows hypervascularity, structural inhomogeneity and the presence of fatty areas. The latter are particularly useful to rule out renal cell carcinoma. Abdominal CT provides information on possible bleeding. Once current or recent signs of extravasation are detected at CT scan, a sudden selective arterial embolization should be required in order to perform a nephron-sparing treatment and to avoid radical or partial nephrectomy.
The treatment of choice for a hemorrhagic AML is transcatheter selective or super-selective arterial embolization (SAE). SAE is less invasive than a surgical intervention and enables targeted treatment of bleeding vessels with a low risk of severe complications. Although technical success has been reported to be achieved in 80 to 90% of AMLs treated with SAE, long-term follow-up has shown tumour recurrence in over 30% of patients, with a higher recurrence rate of 43% in patients with TSC. At 5 years and 10 years from initial SAE, the rate of reembolisation was 29% and 63%, respectively. For this reason, patients with TSC-LAM who underwent SAE for AMLs should be surveilled to detect possible recurrences. Moreover, SAE has been demonstrated to avoid renal surgery in patients with AMLs. The need for surgical operation for AMLs following SAE is 4% at 5 years and 10 years and is associated with the failure of initial embolization.
Alternative treatments for AML are radical or partial nephrectomy and mTOR inhibitors.  Arterial embolization for AMLs is also performed for preventing haemorrhages in at-risk lesions. The risk of spontaneous haemorrhage increases significantly to 50-60% in lesions greater than 4 cm or with the presence of aneurysmal blood vessels. [4,8]
Haemorrhagic renal AML must be suspected in patients with LAM presenting with flank pain or shock. A CT abdominal scan should be performed in order to correctly plan the treatment of AMLs.
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