Proof of strong beta-catenin-expression in stromal cells and endothelial cells stress possible importance of the APC/beta-catenin-pathway in angiofibromas, but gives no certain evidence for the assumption that stromal cells may be the neoplastic cells. As beta-catenin can increase sensitivity of the androgen receptor, it may be assumed that the increased beta-catenin-expression in angiofibromas is involved in the typical growth stimulus of this tumor in adolescent males.

Different classifications of EMP described in the literature are discussed. If these classifications are applied to our cases neither the tumor stage nor the histological picture allow definite conclusions about the prognoses to be drawn. Metastases in regional lymph nodes do not necessarily mean a worse prognosis. Overall, compared to MM with a ten year survival rate of 18% the prognosis is more favorable in EMP with a ten year survival rate of 50%. After a generalized plasma cell neoplasia has been excluded EMP in the head and neck should be treated like a locally aggressive and potentially metastatic tumor. From our experiences we recommend a primary surgical therapy followed by radiation therapy if necessary.

Progression of a tubular adenoma to an adenocarcinoma like in the adenoma-carcinoma model well known for colorectal carcinomas has so far not been observed within the paranasal sinuses. But, an adenocarcinoma already present at the time of first surgery can not be ruled out completely in the presented case as histopathological evaluation may have failed to detect an adenocarcinoma in the available specimens after first surgery. Either malignant transformation of a tubular adenoma had occurred or proof of an adenocarcinoma has failed with misdiagnosis of a tubular adenoma. A tubular adenoma as well as an adenocarcinoma require complete resection and careful clinical and radiological follow-up to avoid adenocarcinoma development from a tubular adenoma or to detect an adenocarcinoma by histological evaluation of the whole specimen.