Recurrent intranodal palisaded myofibroblastoma with metaplastic bone formation

Intranodal palisaded myofibroblastoma (IPM) is a rare primary nonlymphoid tumor of the lymph node, which can easily be mistaken for other spindle cell tumors. Intranodal palisaded myofibroblastoma is thought to arise from intranodal myofibroblasts, a finding that is supported by its immunophenotype, positive immunostaining for actin and vimentin, and negative immunostaining for desmin. Characterized by a benign clinical course, IPM is treated by simple surgical excision. We describe a 49-year-woman, who had cadaveric renal transplantation in 1992 and recurrent IPM 41/2 years after its original excision. To our knowledge, this case represents only the second known case of recurrent IPM. The histologic feature of metaplastic bone formation in this case has not been previously described in IPM.