Slowly developing perigraft seroma after a modified Blalock-Taussig shunt.

We report a 26-year-old patient with slowly developing perigraft seroma 15 years after a modified Blalock-Taussig shunt with an expanded polytetrafluorethylene graft. The mediastinal mass was first observed on a chest x-ray film 8 years after the shunt operation. The mass contained massive gelatinous or organic tissues with a severely calcified pseudocapsule, and it was adjacent to the calcified but functioning graft. No fluid collections were noted. The histological findings were compatible with a seroma. No recurrence was noted on last follow-up 1 year postoperatively.