A case of chronic expanding hematoma in the tensor fascia lata.

We describe a patient in whom a chronic expanding hematoma was pathologically confirmed by examination of the resected specimen. It developed gradually in the left lateral thigh, which had been bruised 8 months before, but had produced no mass-related symptoms initially. Computed tomography (CT) showed the mass to be homogeneous with capsule formation, whereas ultrasonography showed it to resemble a multilocular cyst. The lesion was treated by complete excision of a perifascial mass. Grossly, a well-circumscribed, fusiform mass with a soft cystic center and a fibrous pseudocapsule was observed. Histologically, the mass was composed of necrotic debris, fibrin and blood clots. This was surrounded by a rim of hyalinized fibrous tissue with a chronic inflammatory infiltrate and granulation tissue with sprouting new capillaries. CT was unable to discriminate the chronic expanding hematoma from other soft tissue masses, ultrasonography being needed to reveal its characteristics in this case.