Sinonasal malignant peripheral nerve sheath tumors (MPNST) are infrequent neoplasms. 16 cases of low-malignant MPNST in this localization were retrieved from the files of soft tissue tumors established in Jena. They were examined with regard to their morphology and immunohistochemistry. The importance of an only partial immunostaining by S100 protein antibodies for diagnosis and differential diagnostic discrimination to benign peripheral nerve sheath tumors (schwannomas and neurofibromas) is explained. Finally, the differential diagnosis of spindle cell tumors in the sinonasal region in general is briefly discussed.