Scars and stretch marks are extremely common. For scars, evidence of alterations of the dermal and hypodermic layers is known, while for stretch marks, less data are available, and they are considered purely aesthetic conditions. The intra- and inter-subject variability of the skin makes the comparison between these two particularly complex. This study presents the case of a 54-year-old man who had both stretch marks and a surgical scar on his abdomen. We performed ultrasound and elastosonographic investigations for both to analyse the structural alteration of the skin and subcutaneous layers. Their structures were also compared to the structure of intact skin. The two skin conditions appeared substantially morphologically different and different from intact skin. The alterations detected, particularly of the connective structures, allow us to state that both scars and stretch marks are alterations of both the dermis and the hypodermis and stretch marks differ from scars.