Abdominal wall tumours comprise a broad histopathological spectrum and the accurate knowledge of their appearance facilitates the correct diagnosis and optimal patient treatment. Because of the peripheral location within the abdominal wall, these lesions are best suited to be examined with sonography and, in case of equivocal appearance, they can be additionally characterized with CT or MRI. Additional advantages of sonography in the analysis of these lesions are the high spatial resolution, the evaluation of the vascularization in Doppler mode, the focused examination on the painful/swollen area and the guidance of interventional procedures such as biopsy.

The abdominal wall includes the following layers, each of them being individually detectable with sonography [1] (Figure 1):

-  Skin

-  Subcutaneous adipose tissue

-  Muscular layer with symmetrical pattern on each side of the linea alba, including medially the rectus abdominis muscle and laterally (overlapping)  the external oblique, internal oblique and transverse muscles

-  Properitoneal fat tissue

-  Parietal peritoneum

Tumours can develop within either of these layers. Furthermore, the same histological type of tumour, as for example desmoid, can develop in distinct abdominal wall layers and, depending on the location, can present with different imaging features (see below).