Typology of intravesical prostatic protrusions, or so-called median lobes, in middle-aged and older men

Changes related to prostatic ageing include an increase of prostate volume and morphologic distortions of the prostatic edges in middle-aged and older men. These changes of the prostate exhibit a certain level of heterogeneity, which is clinically obvious for surgeons, radiologists, and anatomists, and which can be explained by the complex nature of the embryologic/anatomic development of the prostate. While the etiology of the median lobe has typically been attributed to a growth and protrusion of the prostatic area at the top of the utricle, we argue that this is not necessarily the case as intravesical protrusions of the prostate have also been observed laterally and anteriorly to the bladder neck, suggesting the involvement of other prostatic zones, thereby highlighting the need to refine the concept of the median lobe.

The current study examined a large series of 478 prostate magnetic resonance imaging scans (MRIs). Intravesical prostatic protrusions were classified, based on their topography: anterior (A), posterolateral (P), and dual (D). Data were analyzed using MedCalc^®11.6.1.1.0 software. Pearson's correlations with coefficients (r) and P values were calculated for the patient's age, prostate volume, and IVPP size.

An intravesical prostatic protrusion was observed in 27% of cases, with type A occurring in 18% (3% isolated), type P in 96% (81% isolated), and type D in 15%.

The new insights regarding the variability in prostate anatomy will contribute to the improved management of prostate hypertrophy by radiologists and surgeons.