A CASE OF GIANT-CELL REPARATIVE GRANULOMA OF THE PETROUS BONE - DEMONSTRATION OF THE PROLIFERATIVE COMPONENT

BACKGROUND Giant cell reparative granuloma (GCRG) is an uncommon benig n lesion of the bone. It typically arises in the mandible and rarely i nvolves the skull. The cytologic nature and genesis of the involved ce lls are poorly understood. METHODS AND RESULTS We report a case of GCR G in the petrous bone of a 3-year-old girl. One year following gross t otal removal, the granuloma recurred locally and was resected en bloc at the second surgery. Histologically, the lesion was composed of oval or spindle-shaped stroma cells admired with a number of multinucleate d giant cells, Immunohistochemical study demonstrated that 5.6% of the stroma cells, but none of the multinucleated giant cells, were positi ve for MIB-1 antibody. CONCLUSION These results suggest that this lesi on expands by proliferation of the stromal component, with a growth ra te roughly between those of the typical benign and malignant brain tum ors. The cytologic nature of the cells comprising this uncommon diseas e remains to be elucidated. (C) 1997 by Elsevier Science Inc.