What Causes Bump On The Legs With Pain?

My husband keeps getting these strange bumps on his legs in the evenings... S/S: at least half the size of a fist, colorless, tender feels like a bruise , no temperature difference, come out of no where and progressively get more painful, appear in the late afternoon/evening and go away during his sleep. It is very strange to me. They feel soft and look like he a goose-egg on his leg, or like someone punched him really hard developing a large welt. However, they are the same color as his skin! I was worried about a DVT but they don t have all the signs. Help!