G. Petur Nielsen, MD

Andrew E. Rosenberg, MD

Specimen radiograph shows chondroblastoma of the femoral condyle. The large tumor fills the medullary cavity, has a lobular configuration, a sharp sclerotic margin, and is lucent with internal mineralization.

Resected femoral condyle contains an intramedullary chondroblastoma. The oval tumor is well circumscribed, tan-pale yellow, and hemorrhagic. The overlying articular cartilage is unremarkable.



  • Chondroblastoma (CBA)


  • Calcifying giant cell tumor

  • Codman tumor

  • Epiphyseal chondromatous giant cell tumor


  • Benign cartilage-producing neoplasm composed of chondroblasts that typically arises in epiphysis of skeletally immature individuals



  • Presumably develops from mutations in intraosseous mesenchymal stem cells



  • Incidence

    • Accounts for approximately 1% of primary bone tumors

    • Responsible for < 3% of primary benign bone tumors

    • In individuals younger than 18 years, incidence is 1.18 per million

  • Age

    • Affected individuals are typically skeletally immature, with open growth plates, between ages 10-25 years

    • Rare in young children and elderly

  • Gender

    • More common in males

      • M:F = 2:1


  • Arises in any bone that develops from endochondral ossification

  • Typically develops in epiphysis of long tubular bones (66%)

    • Most common sites are distal and proximal femur, followed by proximal tibia and proximal humerus

    • Approximately 37% limited to epiphysis

    • About 65% involve epiphysis and extend into metaphysis

    • Vast majority are centered in medullary cavity; intracortical and surface tumors are rare

  • Apophyseal origin is less frequent (25%)

    • Usually originates in greater trochanter of femur and greater tuberosity of humerus

  • Bones of hands and feet affected in 10%

  • Other locations include talus, calcaneus, patella, acetabulum, iliac crest, temporal bone, and skull base

  • Tumors arising in metaphyseal and diaphyseal locations are rare

  • Almost all chondroblastomas are solitary

    • Multifocal chondroblastoma is very rare

  • Chondroblastomas in adults develop in unusual locations, such as skull and facial bones


  • Pain

    • Tender on palpation

  • Swelling

  • Limitation of range motion

  • Limping

  • Joint stiffness

  • Pathologic fracture through articular surface

Natural History

  • Slow enlargement associated with increase in severity of pain and other symptoms

  • May locally recur following curettage or incomplete resection

  • Metastases develop in < 1% of patients

    • Usually follows multiple recurrences or patients who present with pathologic fracture

  • Malignant transformation very rare


  • Curettage and packing with bone graft

  • Percutaneous radiofrequency heat ablation in appropriate cases

  • Resection in selected cases

  • Radiation in tumors that are in critical anatomic locations, such as skull base


  • Local recurrence rate: 14-18%

  • Higher recurrence rate in tumors arising in temporal bone and ribs

  • Local recurrences usually develop within 1st 3 years following curettage

    • May be detected after much longer time interval

  • Pulmonary metastases from histologically benign chondroblastomas are well-recognized phenomenon

    • Metastases are slowly progressive

    • Maintain histologic appearance of benign chondroblastoma

    • Rarely fatal and can be treated with resection

    • Usually develop > 5 years after primary diagnosis


Radiographic Findings

  • Intramedullary, eccentric or central, well-defined tumor with sclerotic margins

  • Predominately radiolucent but frequently contains scattered punctate calcifications

  • May scallop cortex or result in its destruction

  • Neighboring marrow is altered by edema

  • Secondary aneurysmal bone cyst-like changes may cause extensive expansion of bone and periosteal reaction, mimicking a more aggressive neoplasm

    • In chondroblastoma with extensive aneurysmal bone cyst-like changes, it can sometimes be difficult to identify features of underlying primary chondroblastoma

MR Findings

  • Chondroblastoma has low or intermediate signal intensity on T1-weighted image and may be obscured by surrounding edema

  • Tumor has high or variable intensity on T2-weighted image

  • Prominent edema in marrow and soft tissue

  • Joint effusion is common

CT Findings

  • Chondroblastoma is oval, well demarcated, and shows internal calcifications

Bone Scan

  • Marked increased activity on bone scan


General Features

  • Well circumscribed, round or oval, red-gray-white, and gritty

  • Hemorrhagic cystic areas common and are prominent in tumors with secondary aneurysmal bone cyst-like changes


  • Range in size from 1-19 cm (average: 3.6 cm)

  • 85% are ≤ 5 cm


Histologic Features

  • Densely cellular with sharp margins and surrounding reactive bone

  • Composed of admixture of mononuclear chondroblasts and multinucleated osteoclast-type giant cells

  • Chondroblasts grow in sheets, have eosinophilic cytoplasm delineated by well-defined cell borders

  • Nuclei are eccentric, reniform or coffee-bean-shaped, similar to nuclei in Langerhans cell histiocytosis

  • Mitotic activity and regional necrosis may be present, the latter especially in calcified areas

  • Chondroid matrix can be pink or basophilic and sometimes resemble woven bone

    • Well-formed hyaline cartilage uncommon

  • Mineralization of matrix surrounding individual cells imparts characteristic “chicken wire” pattern

  • Osteoclast-type giant cells scattered throughout tumor, usually most numerous in areas of matrix production and hemorrhage

    • Osteoclast-type giant cells are nonneoplastic and recruited by chondroblasts

  • Chondroblastoma abutting temporomandibular joint frequently shows intracytoplasmic hemosiderin deposition mimicking tenosynovial giant cell tumor

    • Some cases reported in literature likely represent tenosynovial giant cell tumor

  • Necrosis in fractured tumors and in areas of prominent calcification

  • Vascular invasion uncommon

  • Concept of “malignant” chondroblastoma is controversial

    • Some pathologists believe that most of these tumors represent either misdiagnosis or radiation-induced sarcoma

  • Term “aggressive chondroblastoma” is used for tumors that histologically have features of chondroblastoma but show destructive growth pattern radiographically

  • Tumor in metastatic deposits similar to that of primary and frequently surrounded by rim of reactive bone



  • Clonal abnormalities especially involving chromosomes 5 and 8 have been identified

  • Recent study has shown a balanced t(5;17) in chondroblastoma in chondroblasts but not osteoclasttype giant cells


  • Chondroblasts express S100 protein and SOX9

  • Tumor cells may stain for muscle actin, keratin, and epithelial membrane antigen

  • Osteoclast-type giant cells stain for histiocytic markers

  • RANKL, a stimulator of osteoclast production and activity, is expressed by tumor cells

    • By this mechanism, osteoclasts are recruited into tumor and produce resorption and lysis of underlying bone

  • Extracellular matrix stains for collagen type II


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Jul 6, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Chondroblastoma

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