Bone & joints

Other chondrogenic tumors

Chondroblastoma



Topic Completed: 18 October 2021

Minor changes: 18 October 2021

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PubMed Search: Chondroblastoma[TI] review[PT]

Ashley Patton, D.O., Ph.D.
Paul E. Wakely, Jr., M.D.
Page views in 2020: 11,433
Page views in 2021 to date: 12,421
Cite this page: Patton A, Wakely PE. Chondroblastoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/bonechondroblastoma.html. Accessed October 25th, 2021.
Definition / general
  • Benign neoplasm; rare (< 1% of primary bone neoplasms), arising in second to third decades of life, with slight male predilection
  • Treatment with surgical curettage is generally curative; recurrence varies with location
Essential features
  • Rare (< 1% of primary bone neoplasms)
  • Peaks in second decade of life, with slight male predilection
  • Common location includes epiphysis of long bones > metaphysis; may involve skull in older patients
  • Sheets of chondroblasts admixed with osteoclast-like giant cells and eosinophilic chondroid matrix; pericellular chicken wire type calcification may be present
  • K36M mutations commonly identified
ICD coding
  • ICD-O: 9230/0 - chondroblastoma, NOS
  • ICD-11: 2E82.Z - benign chondrogenic tumors, site unspecified
  • ICD-11: XH4NK2 - chondroblastoma, NOS
Epidemiology
Sites
Pathophysiology
Clinical features
Diagnosis
Radiology description
  • Xray: well defined lucent lesion with a thin sclerotic rim, with or without matrix calcifications, commonly arising eccentrically within the epiphysis of long bones; extension to the metaphysis can be seen (AJR Am J Roentgenol 1977;128:613)
  • CT scan: can show matrix calcification and solid periosteal reaction (J Comput Assist Tomogr 1984;8:907)
  • MRI: associated with bone marrow edema, periosteal and soft tissue reactions, varying signal intensity on T2 weighted sequences (Skeletal Radiol 2002;31:88)
Radiology images

Contributed by Mark R. Wick, M.D., Borislav A. Alexiev, M.D. and AFIP images

Femur Xray

Foot talus Xray

Humerus Xray

Left acromion lesion

Radiograph of tibia

Prognostic factors
Case reports
Treatment
  • Excision or curettage, with or without bone grafting, is the mainstay of treatment (Acta Orthop Belg 2016;82:68)
  • En bloc resection or amputation is reserved for advanced cases
Gross description
  • When resected with bone: usually 3 - 6 cm, well circumscribed, white-blue-gray, firm
  • When resected as curetted material: reddish, friable material (Arch Pathol Lab Med 2017;141:867)
  • Variable calcification, necrosis, cystic areas
Microscopic (histologic) description
  • Composed of round or polyhedral chondroblasts with abundant eosinophilic cytoplasm and well defined cell borders; spindle shaped cells may be focal (Ann Diagn Pathol 2003;7:205, Cancer 1972;30:401)
  • Nuclei are oval, hyperlobulated with grooves
  • Pericellular lace-like or chicken wire type calcification among degenerative chondroblasts
  • Chondroid matrix almost always present (pink rather than blue matrix)
  • May have marked cellularity, intracytoplasmic glycogen granules, mitotic figures, necrosis and osteoclast type giant cells
  • No significant nuclear atypia as compared with malignant chondroblastoma (Mod Pathol 2020;33:2295)
  • Aneurysmal bone cyst-like change is common (Skeletal Radiol 2010;39:583)
Microscopic (histologic) images

Contributed by Ashley Patton, D.O., Ph.D. and AFIP images

Chicken wire calcification and mature cartilage formation

Osteoclast-like giant cell

Sheets of chondroblasts


Nuclei vary in size

Neoplastic cells with ovoid to spindled nuclei

Well formed chondroid matrix

Chicken wire appearance

Cytology description
  • FNA demonstrates clusters of uniformly round to oval cells with loose matrix and scattered multinucleated giant cells (Cancer Cytopathol 2018;126:552)
Cytology images

Contributed by Borislav A. Alexiev, M.D.

Giant cell rich lesion

Positive stains
Negative stains
Electron microscopy description
  • Resembles tissue culture epiphyseal cartilage cells with prominent fibrous lamina that causes microscopic well defined cell borders (Cancer 1972;30:401)
Molecular / cytogenetics description
Videos

Histological overview of chondrosarcoma

Sample pathology report
  • Left femur, resection:
    • Chondroblastoma
Differential diagnosis
  • Chondromyxoid fibroma:
    • Metaphyseal, myxoid with pseudolobular pattern with pleomorphic stellate cells
    • Negative for K36M
  • Giant cell tumor:
    • Metaphyseal or epiphyseal in patients with closed epiphysis (third decade of life), clustered giant cells that are larger and more numerous and uniformly distributed than chondroblastoma, no chondroid matrix or chicken wire matrix
    • Negative for K36M
  • Aneurysmal bone cyst:
  • Chondroblastoma-like osteosarcoma:
    • Histologically, chondroblastoma-like osteosarcoma is characterized by monotonous, minimally to moderately atypical rounded cells with ovoid nuclei resembling chondroblastoma and abnormal osteoid deposition with destruction of the bone (Arch Pathol Lab Med 2020;144:15, Orthopedics 1999;22:337)
    • Negative for H3K36M
Board review style question #1


An 18 year old man presents with a 3 cm, well defined lucent lesion within the epiphysis of the distal femur. Microscopic features of the surgical curettage specimen are represented by the H&E images. The best diagnosis is

  1. Chondroblastoma
  2. Chondroblastoma-like osteosarcoma
  3. Chondromyxoid fibroma
  4. Giant cell tumor of bone
Board review style answer #1
A. Chondroblastoma. Chondroblastomas commonly present in the second decade of life as a singular, well defined lucent lesion within skeletally immature long bones. Characteristic histopathological features include sheets of chondroblasts admixed with osteoclast-like giant cells in a chondroid matrix and focal chicken wire type calcification. Chondroid fibromas typically lack chicken wire type calcification. Chondroblastoma-like osteosarcomas generally display an infiltrative growth pattern with marked cytologic atypia. Chondroid matrix is not commonly seen in giant cell tumor of bone.

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Reference: Chondroblastoma
Board review style question #2
Which of the following is a feature of chondroblastoma?

  1. Aggressive lesion with an infiltrative growth pattern
  2. Commonly arises in the epiphysis and metaphysis of long bones
  3. Generally shows a high degree of cytologic atypia
  4. Lacks a pericellular chicken wire calcification
Board review style answer #2
B. Commonly arises in the epiphysis and metaphysis of long bones. Chondroblastomas show pericellular chicken wire calcification and generally display well demarcated borders and a lesser degree cytologic atypia when compared with chondroblastoma-like osteosarcoma.

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Reference: Chondroblastoma
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