A 65 year old female patient was admitted to our hospital with unspecific symptoms and a lump in the right groin which raised suspicion of a malignant lymphoma. Histologically a follicular dendritic reticular cell tumor was found. Because there are aggressive forms of this tumor and no established standard therapy, we decided to treat her with surgery followed by a combined radio- and chemotherapy. Despite this treatment 16 months after the first diagnosis a relapse occurred with a metastasis of the follicular dendritic cell tumor in the lung. The metastasis was resected surgically. The optimal management of this kind of tumor is not known.