[Inflammatory fibroid polyp, a rare tumor of the appendix]. / Le polype fibroïde inflammatoire, une tumeur rare de l'appendice.

ABSTRACT

We report the rare occurrence of an inflammatory fibroid polyp of the appendix. The lesion was diagnosed in a 33-year-old woman presenting with abdominal pain, fever and localized tenderness in right iliac fossa on abdominal palpation. CT-scan showed an 8 cm appendiceal mass and a laparoscopic appendectomy was consequently performed. On microscopic examination, the tumor consisted of spindle cells dispersed in a loose fibromyxoid stroma containing numerous blood cells and inflammatory cells with abundant eosinophils. On immunohistochemistry, the spindle tumor cells were positive for vimentin, fascin and focally for CD34 and CD35. They were negative for smooth muscle actin, desmin, CD21, CD23, CD117 and S100 protein. Inflammatory fibroid polyp is a rare benign mesenchymal tumor of the gastrointestinal tract rarely reported in the appendix. This tumor shares some common pathologic features with the myofibroblatic inflammatory tumor but they are two different entities. The pathogenesis of this tumor remains unclear but fascin and CD35 immunoreactivity of the tumor cells suggests a probable dendritic cell origin.