What Causes Bruise Above The Naval?

ok, i have noted a small bruise about the size of a nickel about 6cm next to midline and about 6 cm above the navel. it is sore to touch and I palpate a hard node. This just appeared 3 days ago. no fever or chills or abnormal bathroom issues. I am considering going to er to have maybe ultra sound.. not sure .. but is worrisome. I am a male, 43 years old aprox 160lbs and have positive hx of cutaneous lymphomia, some cardiovascular hx in family, but not me.