Scrotal swelling: Consider all possibilities

A 75-year-old male presented at the emergency department following thoracic trauma, for which a chest Computed Tomography (CT) was requested.

On the 5^th day of admission, the patient accidentally fell on the bathroom floor and later started complaining of bilateral painless scrotal enlargement.

During the emergency stay, the patient underwent a chest CT, which revealed a fracture of the right seventh rib, a small right pneumothorax and a pneumomediastinum. It also showed a massive subcutaneous emphysema, extending from the neck base to the proximal abdominal wall, mostly on the right side. No pneumoperitoneum was noticed (Figure 1).

After the fall as an inpatient, the scrotum appeared enlarged bilaterally, so an ultrasound was requested. It demonstrated homogeneous testicles with normal echostructure, no hydrocele or collections. However, it displayed many hyperechogenic foci with “dirty shadowing” artefact, suggesting the presence of air in the scrotum (Figure 2), which was confirmed by an x-ray (Figure 3). A pelvic CT was obtained for better characterisation and showed moderate-large amount of gas dissecting the scrotum and spread of the subcutaneous emphysema from the upper abdomen to the scrotum through the abdominal fascias (Figure 4).

Pneumoscrotum is a rare clinical condition and refers to the presence of air within the scrotum, either in subcutaneous tissues or in tunica vaginalis.

Pneumoscrotum may have many aetiologies, including iatrogenic and pathological causes. It has been reported after some diagnostic and therapeutic techniques, in particular gastrointestinal endoscopic procedures, thoracic and abdominal surgeries and mechanical ventilation. It may also be due to various conditions, such as pneumothorax, pneumomediastinum, hollow viscera perforation and local infection [1–3].

There are some pathophysiological mechanisms that explain the presence of gas within the scrotum. Firstly, air in the scrotum may originate from local sources, either from infection with gas-producing microorganisms, such as in Fournier´s gangrene, or from direct scrotal trauma. However, air can spread from other parts of the body into the scrotum. Air may travel from the lungs across the Camper's and Scarpa's abdominal fascias down to where they fuse at the scrotum, forming the Dartos fascia (Figure 5). Also, intraperitoneal air may enter the scrotum via a patent processus vaginalis, which is an embryological variant. Lastly, retroperitoneal air can reach the scrotum through the inguinal canal [2–4].

In the present case, the air from the lungs accumulated mainly in the right hemithorax in the form of subcutaneous emphysema and travelled along the abdominal wall to the scrotum.

Clinically, pneumoscrotum presents with scrotal swelling, usually with no pain or tenderness, and possibly with crepitus [3]. Since the scrotal wall is elastic and compliant, pneumoscrotum does not compromise vascularity or cause compression of the urethra [5].

Imagiologic studies, especially x-rays and computed tomography of chest, abdomen and pelvis, may be of great importance since they allow the visualisation of air within the scrotum and help to identify the origin of this condition. Ultrasound may be helpful to exclude hydrocele, haematocele, orchiepididymitis or intra-abdominal pathology.

Pneumoscrotum itself is a benign entity, though often associated with more serious conditions, sometimes life-threatening. Therefore, treatment of pneumoscrotum is usually conservative and directed towards the underlying condition [6].

All patient data have been completely anonymised throughout the entire manuscript and related files.