Chronic expanding hematoma.

Two cases of chronic expanding hematoma are presented. Although the location and presentation vary, chronic expanding hematoma has a distinct histopathologic pattern. A diagnosis of neoplasm is suggested by its slow growth pattern. The criteria for their formation are incompletely understood, and in one case, a hematoma occurred despite apparent adequate drainage. Computed tomography is helpful in distinguishing chronic expanding hematoma from other soft-tissue masses.