In Situ Hybridization and Immunocytochemical Evidence Supporting a Cartilaginous Origin

Abstract

Chondroblastoma is a rare benign epiphyseal lesion of bone. Previous immunocyto chemical studies have shown a pattern of staining similar to normal cartilage. The authors studied five cases of chondroblastoma by in situ hybridization and immunocy tochemical methods to further characterize these lesions. In situ hybridization, using a digoxigenated oligonucleotide cDNA probe, demonstrated type 2 collagen mRNA in mononuclear stromal cells, especially in areas of matrix formation. Immunocytochem istry demonstrated variable staining with epithelial and neural markers, as well as a scattered population of stromal cells that stained with histiocytic markers. The demon stration of type 2 collagen mRNA in this lesion supports a cartilaginous origin. The presence of histiocytic cells within the stroma most likely represents a reactive compo nent to the lesion. The results of this study provide immunocytochemical and molecu lar evidence supporting a cartilaginous origin for this benign neoplasm. Int J Surg Pathol 1 (3):155-162, 1994