2 cm in size.- Well demarcated.- Stippled / ringlike flecks of matrix calcification.# MC Location = spine (in posterior elements) followed by long bone diaphysis (e.g., femur).CHONDROBLASTOMA (Codman tumor)# 1% of primary bone neoplasms, and epiphyseal in origin.# Peak in 2nd decade.# Histologically,'chicken wire' calcification (pericellular deposition of calcification) is virtually PATHOGNOMONIC. # MC location = long bones (80%); 2/3 in lower extremity, 50% about knee.# Radiological features:- eccentric medullary, subarticular location with open growth plate (98% begin within epiphysis)# DD: (*) Giant cell tumor (usually larger + less well demarcated, not calcified, older age group with closed growth plate),">