Follicular dendritic cell tumor of the mediastinum: expression of fractalkine and SDF-1alpha as mast cell chemoattractants.

Follicular dendritic cell tumor (FDCT) is a rare tumor mainly located in laterocervical lymph nodes. We report one case of mediastinal FDCT associated with a history of bullous skin disease and clinically obvious immunosuppression. This tumor was characterized by heavy mast cell infiltration. Mast cells were in close relationship with tumor cells as demonstrated by ultrastructural examination and their presence are probably related with the strong expression of mast cell chemoattractants as fraktalkine and stromal cell-derived factor-1alpha by tumor cells. The long follow-up period of more than 17 years allowed to us assess the relatively indolent evolution of this tumor characterized by three slowly growing local recurrences without metastasis.