Renal leiomyoma
Renal leiomyomas are benign tumors of the kidney originating from smooth muscle cells of the renal capsule, pelvis, calyces, or blood vessels.
There is a 4-5.5% prevalence based on autopsy findings.
Clinical presentation
Renal leiomyomas are usually incidental findings. In symptomatic cases, these lesions can cause abdominal/flank pain and/or palpable mass.
Pathology
At macroscopic examination, leiomyomas are typically well-demarcated, solid, firm nodules with rare calcifications and cystic changes, without necrosis.
Microscopically, spindle cells with few nuclear polymorphisms and no mitotic activity are arranged in intersecting fascicles.
Diagnosis
Diagnosis in based on histological analysis.
Radiographic features
Ultrasound
Ultrasound may display a solid or cystic mass and allow for identification of a plane between the tumor and kidney, but has very poor specificity .
DSA-angiography
- can be either hypo- or hyper-vascular
- features indicative of malignancy (e.g. vessel encasement, renal vein invasion, arteriovenous shunting) are absent
CT
Computed tomography scanning provides improved anatomic definition and reveals well-circumscribed margins, a capsular/subcapsular or peripelvic origin, minimal parenchymal distortion, and no evidence of extra-renal invasion. Some suggest attenuation value, location and margins of the lesion can help to address the diagnosis of renal leiomyoma.