Left inguinal hernia mimicking metastasis on bone scan.

Inguinal hernia is a well-known entity that usually affects males. The most common herniated organs are parts of the bowel, omentum, or fat. Urinary bladder herniation into the inguinal region is very rare and is often diagnosed during inguinal hernia surgery. This case highlights the importance of additional views and anatomic imaging to accurately interpret the unusual scan findings.

Case report

An elderly male was referred for a bone scan for evaluation of osteomyelitis in the sacral region. On delayed images, there was a coincidental linear focus of activity in the region of the left thigh, which seemed to be in the inferior pubic ramus—raising suspicion of osseous metastasis (Fig. 1). A lateral view showed this activity to lie within the soft tissue anterior to the bones (Fig. 2), which was confirmed by the SPECT imaging. A subsequent CT scan of the pelvis showed a left inguinal hernia containing fat, as well as a part of the urinary bladder in that region (Figure 3, Figure 4). The portion of urinary bladder within the inguinal hernia measured approximately 4.4 × 3.5 cm on the CT scan.

Figure 1

Elderly male with left inguinal hernia. Bone scan shows inear focus of activity in the region of the left thigh.

Figure 2

Elderly male with left inguinal hernia. Lateral view shows that activity lies within the soft tissue anterior to the bones.

Figure 3

Elderly male with left inguinal hernia. CT scan of the pelvis shows a left inguinal hernia containing fat, as well as a part of the urinary bladder.

Figure 4

Elderly male with left inguinal hernia. CT scan of the pelvis shows a left inguinal hernia containing fat, as well as a part of the urinary bladder

Discussion

Herniation of the urinary bladder into the inguinal region is very rare. It is reported to be present in 0.4–3% of the general population (1). There have been scattered case reports in the surgical and nuclear medicine literature about the condition (2, 3, 4), which is often diagnosed during inguinal hernia surgery. The preoperative diagnosis of bladder herniations is important to prevent the possible iatrogenic trauma that can occur during surgery (5). This case highlights the importance of additional views and anatomic imaging to accurately interpret the unusual scan findings.