Prostatic leiomyomas are benign mesenchymal tumors of the prostate.
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Epidemiology
Prostatic leiomyomas are very rare 1-3.
Diagnosis
The diagnosis of prostatic leiomyoma is based on histology.
Clinical presentation
Prostatic leiomyomas can present with voiding difficulties or obstructive symptoms 1.
Complications
Complications of prostatic leiomyomas include acute urinary retention 1.
Pathology
Leiomyomas of the prostate are characterized as benign smooth muscle tumors without any glandular elements located within the prostate or in a juxta-prostatic position 1-4.
Macroscopic appearance
Grossly tumors have been described as well-circumscribed with a glistening or smooth surface and a multilocular cystic cut surface 5.
Microscopic appearance
Microscopically leiomyomas of the prostate are characterized by the following histologic features 5,6:
bland spindle cells with a prominent eosinophilic cytoplasm
organized fascicular architecture
no or rare nuclear atypia
no or scarce mitoses
no necrosis
Immunophenotype
Immunohistochemistry stain should express desmin or smooth muscle actin but should be negative for CD34 1-3.
Radiographic features
Ultrasound
On transrectal ultrasound, leiomyomas have been described as nonspecific hypoechoic or hyperechoic masses 2-4.
CT
Computed tomography might show a heterogeneously enhancing but otherwise noninvasive appearing soft tissue mass 2,4.
MRI
On prostate or pelvic MRI have been characterized as well-delineated and without signs of invasive behavior 2-4.
Signal characteristics
T1: overall isointense
T2: hypointense to slightly hyperintense with hyperintense foci (compared to muscle)
DWI: diffusion restriction (hyperintense on high-b value, hypointense on ADC)
DCE (Gd): homogeneous slow enhancement
Radiology report
The radiological report should include a description of the following:
form, extent and location of the tumor
description of its borders
relation to seminal vesicles, bladder and rectum
Treatment and prognosis
Management options consist of surgical excision either as transurethral resection or prostatectomy. Prognosis is excellent if excised completely 1-3. More recent options include prostate artery embolization or active surveillance in asymptomatic patients 2,3.
History and etymology
The first case of prostatic leiomyoma was reported by Lebec et al in 1876 1. The definition has been formulated by Kaufmann and Berneike in 1951 1,7.
Differential diagnosis
Conditions that may be mimicking the clinical presentation or imaging appearance of prostatic leiomyomas include 1: