Diagnose this unusual case in gastroenterology.
D006801:Humans; D007414:Intestinal Neoplasms / Q000175:diagnosis*; D007583:Jejunum; D007890:Leiomyosarcoma / Q000175:diagnosis*; D008297:Male; D008551:Melena / Q000175:diagnosis; D008875:Middle Aged; D009336:Necrosis; D014456:Ulcer / Q000175:diagnosis