Fig. 4

Combined histopathomorphological findings of Case 2 and 3, Haematoxylin and Eosin (H&E). A continuous smooth lining of cartilage, deviating into the bone at the partition’s connection site (bar = 1 mm). B cystic change of the subchondral bone with marked sclerosis of the adjacent bone (arrows) (bar = 1 mm). C retained cartilage cores (black arrows) at a connection site of one of the partitions near the outer concentric layer of a subchondral bone cyst (white arrows) (bar = 500 μm). D densely-packed highly vascular aspect of cysts, with adjacent sclerotic bone (arrow) (bar = 200 μm). E myxoid-like aspect of the cysts, surrounded by more densely-packed fibrous tissue (arrows) (bar = 100 μm). F island of tissue in the fibrous cystic wall resembling synovial membrane (arrows) (bar = 200 μm). G chondrone formation in the articular cartilage (bar = 100 μm). H fibrocartilaginous tissue at the partition’s connection sites (bar = 100 μm). B, C, D, E, G and H Case 2, LF navicular bone. A and F: Case 3, LH navicular bone; * = tissue processing artefacts