Solitary fibrous tumor of the oral cavity - An uncommon location for a ubiquitous neoplasm

Solitary fibrous tumor is an uncommon soft tissue tumor initially reported in the pleura but recently described in other sites of the body. To date, o nly 5 examples of oral solitary fibrous tumor have been reported. Here, we describe 2 additional cases of this tumor in the oral cavity. The tumors we re composed of small to medium-sized spindle cells with bland cytologic fea tures; these cells were haphazardly arranged in highly cellular sheets or i ll-formed fascicles as well as in hypocellular areas with hyatinized blood vessels. Both tumors contained blood vessels with a hemangiopericytomalike appearance and expressed vimentin, CD34, and CD99. One case was also strong ly positive for bcl-2. The diagnosis of solitary fibrous tumor may be diffi cult inasmuch as it shares a number of histologic features with other soft tissue tumors. Awareness of its occurrence in the oral cavity is important so that confusion with other spindle cell neoplasms can be avoided.