A sonogram shows an ill-defined superficial mass beneath a surgical incision. What is the most likely diagnosis?

In the context of a sonogram showing an ill-defined superficial mass beneath a surgical incision, an abscess is the most likely diagnosis. Abscesses typically present as irregularly shaped masses characterized by a collection of pus that can occur post-surgery due to infection. They are often surrounded by edema and can cause considerable changes to the surrounding tissues, leading to ill-defined borders on imaging.

The presence of a surgical incision suggests a potential source of infection, making an abscess a plausible complication. In addition, other signs of inflammation, such as increased blood flow to the area seen on Doppler ultrasound, can support the diagnosis of an abscess.

While seromas, hematomas, and lymphoceles can also occur post-operatively, their characteristics differ. Seromas are fluid collections that result from the accumulation of serum and tend to be more well-defined. Hematomas result from bleeding and can appear as a more homogeneous mass or may be well-defined based on their age and organization. Lymphoceles are collections of lymph fluid, typically well-circumscribed and not usually associated with inflammation or infection like an abscess.

Thus, given the ill-defined nature of the mass and the context of its occurrence after surgery, an abscess is the