Urgent-setting magnetic resonance imaging allows triage of extensive penoscrotal hematoma following blunt trauma.

Although uncommon, blunt trauma to the perineum may cause serious injury to the penis. Differentiation between penile fracture with torn tunica albuginea versus extratunical or cavernosal hematomas is crucial because the former condition needs early surgical repair to avoid future deformity and erectile dysfunction, whereas approach is conservative with even large penoscrotal hematomas with albugineal integrity. Urgent-setting magnetic resonance imaging including multiplanar images of the injured penoscrotal region allows precise identification or exclusion of presence, site, and extent of tears of the tunica albuginea, providing a consistent basis for therapeutic choice.

INTRODUCTION

Rarely, perineal traumas cause nonpenetrating injury to the flaccid penis, with the cavernosal crura crushed against the pelvic bones producing extratunical or cavernosal hematomas and usually intact thick fibrous tunica albuginea. Conversely, penile fracture results from abnormal force applied while in erection, usually during sexual intercourse: the patient typically complains of a “cracking” sensation corresponding to tearing of the thinned albuginea, followed by rapid detumescence, severe pain, swelling and deformity. Differentiation between these two conditions is crucial because penis fracture is a serious urological emergency requiring early surgical repair to obviate complications such as erectile dysfunction and deformities, whereas scrotal wall hematomas due to blunt trauma usually resolve well with conservative management, only the largest ones requiring evacuation.[12]

CASE DESCRIPTION

A healthy 40-year-old male arrived to Emergency Department after a bicycle fall. At physical examination, the most prominent finding was a painful, extensive ecchymosis and hematoma involving the penis and ventral aspect of the scrotum. The patient urinated without difficulty, macroscopic hematuria was absent and urinalysis excluded significant abnormalities.

Plain radiographs of the pelvic skeleton (not shown) did not disclose bony fractures. In consideration of the association of an atypical history of trauma on a flaccid penis associated with extensive regional hematoma and marked tenderness, the attending Urologist requested emergency magnetic resonance imaging (MRI) to be performed, including focused multiplanar T1-, STIR and T2-weighted sequences acquired with the penis in a neutral position [Figure 1]. A diffuse, subcircumferential T1- and T2-hyperintense subacute hematoma involved the superficial skin and subcutaneous planes of the entire penis, perineal region and anterior aspect of the scrotum. The low-signal tunica albuginea was recognizable along the penile shaft, without appreciable discontinuities suggesting a possible penile fracture. No signs of hematoma were noted in the spongiosum and cavernosal bodies. The testes (as confirmed by ultrasound, not shown) showed normal size and shape, homogeneous signal intensities and good visualization of their tunica albuginea. The absence of signs of penile and testicular rupture led to conservative treatment option, with resolution of clinical abnormalities after two weeks and no functional complaints.

Figure 1

Sagittal (a) and axial (b) T2-weighted, coronal T1- weighted (c,d) images depict the overall extent of the hyperintense extratunical penile hematoma (*) and allow optimal visualization of the low-signal albugineal tunica (arrows) and its integrity along the entire penile shaft. Both testes show homogeneous intensity and absence of albugineal discontinuities

DISCUSSION

The diagnosis of penile fracture is sometimes possible on clinical grounds, but imaging may be required in patients with atypical clinical presentation, equivocal physical findings or severe pain and swelling prohibiting a thorough physical examination.[123] Imaging diagnosis of penile fracture relies on the detection of albugineal disruption in one or rarely both corpora cavernosa. Tunical tears are usually transversely oriented and commonly involve the ventral portion of the corpus cavernosum at mid- or proximal shaft location, which has to be scrutinized carefully.[1345]

Noninvasive and readily available, ultrasound (US) may be helpful as first-line investigation as it may detect hematomas and albugineal tears. Unfortunately, sonographic assessment of penile trauma requires operator expertise, is usually technically challenging due to penile swelling and pain. According to most Authors, negative US findings cannot rule out rupture.[34567]

Although rarely performed in the acute setting, because of its multiplanar capability and excellent tissue contrast MRI is very useful in the evaluation of penile trauma and provides evaluation of the integrity of anatomical structures even in patients with severe pain and swelling of the penis.[125]

Both extratunical and cavernosal hematomas are easily depicted in their extent and thickness on multiplanar images. Although most reported experiences include a limited number of patients, MRI is considered highly accurate in the identification of presence, location, and extent of discontinuities of the tunica albuginea corresponding to tears, thus helping the urologist in determining the optimal site and extent of the incision. Accuracy of MRI for penile fractures relies on the intrinsic contrast (especially with T2-weighted sequences) between the high signal intensity of the cavernosal erectile tissue and the fibrous tunica albuginea and Buck fascia, usually indistinguishable between them and visualized as a low-signal-intensity thick rim on both pulse sequences. Some authors have advocated the additional use of intravenous contrast in questionable cases, to better delineate the extent of corporal hematoma.[1345]

In the past, cavernosography was used to detect contrast extravasation from corpora cavernosa as a direct sign indicating penile rupture. Currently the use of MRI has superseded cavernosography, which is an operator-dependent, invasive technique that uses ionizing radiation, is painful and associated with not-negligible early and late complications. Furthermore, lacerations obstructed by clots may result in false-negative examinations, whereas small veins may be misinterpreted as tears.[345]

Furthermore, MRI can detect injuries to adjacent structures such as the testes and corpus spongiosum. Associated in up to 30% of penile traumas, urethral involvement may be suggested at MRI by the presence of spongiosal displacement or hematoma. Since the role of MRI is currently unclear, suspected trauma to the penile urethra urethral may still require confirmation and direct visualization by means of cystourethrography.[345]

CONCLUSION

As exemplified by this case, urgent-setting MRI may allow identification of traumatic penile hematoma and confident exclusion of albugineal tear indicating fracture, thereby obviating surgical exploration. In conclusion, trauma to the penis requires prompt clinical and imaging evaluation: the integrity of the tunica albuginea represents the key issue, so MRI is particularly helpful in determining or excluding the need for surgical intervention.[1234]