Imaging of groin masses: inguinal anatomy and pathologic conditions revisited

The groin region is subdivided into two distinct anatomic areas: the inguinal canal and the femoral triangle. A series of cross-sectional imaging cases illustrate that a good understanding of the local anatomic characteristics of the groin allows confident characterization of groin pathologic conditions. Such conditions can be classified into five major groups: congenital abnormalities, noncongenital hernias, vascular conditions, infectious or inflammatory processes, and neoplasms. Congenital entities include hernias, cysts, undescended testis, and retractile testes. Ultrasound (US) is useful in depicting these conditions. In the second group, noncongenital hernias, US allows visualization of bowel loops in peristalsis within the hernia. Herniography, computed tomography (CT), and magnetic resonance (MR) imaging are also helpful in diagnosis. Among vascular conditions, false aneurysms may be detected from the turbulent flow through the tract at Doppler US. The characteristic venous flow of varicoceles is best diagnosed with US during the Valsalva maneuver. Infectious or inflammatory conditions include, among others, hematomas, which appear hyperattenuating at CT and have variable appearances, depending on the age of the blood products, at MR imaging. The origins of neoplasms may be assessed at CT and MR imaging, although appearances of solid tumors are relatively nonspecific.