Table 3.
Patient histology
| Patient | Initial report | Diagnosis on reevaluation |
|---|---|---|
| 1 | (1) Multiple chondroid nodules with focal calcification in areas and ossification; poorly formed connective tissue capsule | BPOP |
| (2) Bone with adjacent fibrous tissue and chondroid material with pleomorphism and occasional binucleate cells with focal calcification and an irregular bone/cartilage interface | BPOP | |
| 2 | (1) Haphazardly arranged nodules of cartilage, bone, and calcified tissue around fibrous connective tissue capsule | Synovial chondromatosis (reported abroad and unable to get specimen) |
| (2) Connective tissue with masses of fibroblastic tissue and cartilage with focal calcification/ossification | BPOP | |
| 3 | (1) Outgrowth of mature lamellar bone and woven bone merging with irregular cartilage cap; cellular island of cartilage toward surface with binucleate chondrocytes and some pleomorphism | BPOP |
| (2) Chondroid component active and pushing into adjacent soft tissues; slightly worrying although not infiltrative | BPOP | |
| 4 | Fragment of cartilaginous tissue with focal calcification and ossification at periphery; chondrocytes are disorganized and degree of pleomorphism; no mitoses | BPOP |
| 5 | (1) Thick proliferative cartilage cap over cancellous bone | BPOP |
| (2) Well-circumscribed nodular osteochondroid nodule in which there is a background myxochondroid/hypercellular periphery surrounding central osteoid component of lamellar and interconnected woven bone; focal heavy calcification; chondroid background is myxoid with hypercellularity but no atypia | BPOP | |
| 6 | (1) Cartilage with irregular margin with bone and large amount of spindle cell tissue with chondroid matrix, mitotic activity, and mild pleomorphism in spindle matrix; clear margin with adjacent dense fibrous tissue | BPOP |
| (2) Cap of moderate cellular cartilage and fibrous tissue underlying irregular enchondral ossification | BPOP | |
| (3) Bone and fragments of proliferating cartilage undergoing irregular enchondral ossification | BPOP | |
| 7 | Multiple nodules of hyaline chondroid tissue partly enclosed by lamellar bone and partly by hyalinized soft tissue; chondroid islands are hypercellular with slight pleomorphism and slightly myxoid background; widespread enchondral ossification and calcification | BPOP |
| 8 | Florid and cellular superficial fibrous component that looks active; deep tissue is chondroid with irregular enchondral ossification | BPOP |
| 9 | Lobulated mass largely of cartilage; cartilage cap has abrupt transition to trabecular bone that has varying calcification; mature and immature bone trabeculae; interspersed loose woven tissue of bland spindle cells without atypia; osteoblastic activity; hypercellular cartilage with increased cytoplasm and open chromatin; well-defined with surrounding dense fibrous tissue | BPOP |
| 10 | (1) Benign osteocartilaginous lesion with bony proliferation | BPOP |
| (2) Proliferating fibrous lesion with cartilage cap and underlying trabecular bone separated by fibrous tissue | BPOP | |
| 11 | (1) Osteocartilaginous lesion with thick cartilage cap in areas of chondrocytes with hypertrophic appearance lying in loose hyaline cartilage; enchondral ossification at base of cartilage that is part typical and part basophilic and irregular; periphery is cellular fibrous tissue with intramembranous ossification with basophilic irregular bony trabeculae; fibrous tissue between irregular bony trabeculae is cellular without atypia | BPOP |
| 12 | Mixture of bone and cellular fibrous tissue; transition between fibroblastic proliferation, mature cartilage, and underlying cortical bone | BPOP |
| 13 | Proliferating spindle cell component cartilage with marked basophilic calcification and enchondral ossification | BPOP |
BPOP = bizarre parosteal osteochondromatous proliferation.