Objective: Although 25-45% of all schwannomas are reported to occur in the head and neck region, nasal cavity and paranasal sinus involvement is rare, with 32 such cases described till 1999. Of these cases, only three were cystic. Herein we present a cystic schwannoma of the maxillary sinus of a 66-year-old, otherwise healthy male patient. Methods: The tumor tissue was routinely processed, embedded in paraffin, and stained with H&E. Immunostaining was performed for S-100 protein, epithelial membrane antigen (EMA) and cytokeratin. Results: A mass with sudden enlargement, inhomogenous enhancement with cystic areas, S-100 positive membrane-like structures lining the cystic cavity of an otherwise classical schwannoma were the main features encountered in our case. Conclusion: We recommend that cystic schwannoma should be kept in mind in the differential diagnosis of cystic masses of the maxilla. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.