Thrombosis of the corpus cavernosum

A 35-year-old male patient with a history of recreational drug use presents with 3 days of perineal pain.

An ovoid lesion that expands, deforms, and replaces the usual signal of the right corpus cavernosum in its posterior region, heterogeneous and hypointense in T2W and slightly hyperintense in T1W, without enhancement after contrast injection. Linear hypodensity is seen on T2W separating the proximal from the distal portion, which could correspond to a fibrous septum.

The left proximal corpus cavernosum shows altered enhancement and signal, possibly related to flow alterations secondary to the right corpus cavernosum process.

Background

A rare entity that occurs in young men (~30 years old) with associated risk factors such as haematological abnormalities, microtrauma secondary to exercise (cycling) or during sexual activity, alcohol or drug abuse, hypercoagulable states associated with dehydration, surgery, tumours, and long-haul flights; also a history of prostatitis, intake of tamsulosin or sildenafil, which consists of thrombosis of the perineal portion of the corpus cavernosum (CC), usually unilateral, although there are isolated bilateral reports [1] (Figure 1).

The pathophysiology is not clear. Weyne et al. describe the presence of a congenital fibrous network at the level of the cruro-cavernous junction or distal to it. This, together with a particular venous anatomy of the crura cavernosa, when perineal pressure is exerted, potentially limits the venous flow of the proximal part of the body. Under normal anatomical conditions, this probably does not pose a problem, since venous blood from the proximal penis can drain via the sinusoidal system into the veins of the distal system. However, if there is a fibrous network, this collateral transport of venous blood to the distal may be affected. Venous blood stasis increases the risk of thrombus formation [2] (Figure 2).

On the other hand, there is a more accurate theory of causality due to the presence of a transverse membrane (fibrous septum) in the proximal portion of the CC that divides it into proximal and distal portions (the proximal always seems to be involved) added to a previous trauma that triggers the thrombotic event [1–3] (Figures 1, 2, 3).

Clinical perspective

It usually presents with perineal or penile pain associated with a palpable mass. Other patients show erectile dysfunction and urinary symptoms that are explained by the mass effect of CC on neighbouring structures. It is important not to confuse this entity with partial priapism because the rigidity in partial thrombosis only affects the proximal portion of the CC; therefore, the distal portion of the penis is flaccid [2] (Figure 2).

Imaging perspective

For diagnosis, Doppler ultrasound is useful as it is readily available and can show volume changes, echogenicity, and absence of vascular flow within the CC, but MRI presents a better characterization of the pathology by excluding other entities and showing the membrane when visible. It is demonstrated by an increase in the volume (Figure 4) of the CC that may displace the contralateral CBD associated with a change in its MR signal, hypointense on T2W images, and hyperintense on T1W = methemoglobin and absence of enhancement ruling out a solid mass. The presence of the septum is seen as a linear hyperintensity on the T1W scan separating the thrombosed part (always proximal) from the non-thrombosed (distal) [2].

Outcome

The current management trend is conservative based on administering anticoagulants, leaving the surgical approach only for those complicated and refractory cases. It has a good prognosis, with no reported recurrence. However, some patients complain of erectile dysfunction with long-term results.

Take home message/ teaching points

In young male patients with perineal pain without an apparent visible cause, it is important to consider this diagnosis to avoid losing time in unnecessary complementary studies. MRI is the gold standard for visualizing the alteration in signal intensity and the membrane causing the condition [2].