Benign renal neoplasm composed of mixture of blood vessels, smooth muscle cells and adipose tissue.
One of the few renal masses that contain fat, and the fat is usually visible on the CT or MRI imaging.
A renal hamartoma.
Evidence suggests monoclonal derivation and cytogenetic studies support neoplastic derivation.
More common in women and rare before puberty.
20% of patients have associated tuberous sclerosis, an autosomal dominant disorder with mental retardation, seizures, and skin lesions.
80% of patients with tuberous sclerosis develop such lesions with an average tumor size of 2-8 cm.
Majority of cases sporadic and unrelated to tuberous sclerosis.
Presentation in the 30’s in patients with tuberous sclerosis and in the 50s and 60s in patients with non tuberous sclerosis associated lesions.
Prevalence of 0.3-3% of all surgically resected renal tumors.
Most likely arises from perivascular epithelioid cells.
Majority of lesions are small and require no treatment.
Large lesions can lead to compression of intraabdominal organs and can have a significant chance of bleeding when larger than 4 cm.