A 70 year-old woman presented with nasal obstruction in 2008. A mass located in nasopharynx was found. Biopsy was sent for histological examination. A new biopsy was taken 3 years later. Histological, immunohistochemical and FISH studies were performed. Results: Histological examination of both biopsies revealed lymphoid hyperplasia, characterized by CD5 and cyclinD1 positive cells of mantle zones, findings consistent with in situ MCL. The diagnosis of in situ MCL confirmed by FISH analysis for t(11;14). The patient examined thoroughly and has remained free of an overt lymphoma to the present day.