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Chondromyxoid fibroma

Authors: Qurratulain Chundriger, M.B.B.S., Nasir Ud Din, M.B.B.S.

Editorial Board Member: Borislav A. Alexiev, M.D.

Editor-in-Chief: Debra L. Zynger, M.D.

Last author update: 17 December 2020

Last staff update: 21 December 2020

Copyright: 2003-2023, PathologyOutlines.com, Inc.

PubMed Search: Chondromyxoid fibroma [TIAB] pathology review [PT]

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Table of Contents

Cite this page: Chundriger Q, Ud Din N. Chondromyxoid fibroma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/bonechondromyxoidfibroma.html. Accessed April 1st, 2023.

Definition / general

Benign cartilaginous tumor of young adults, arising in proximal or distal parts of long bones, showing zonal architecture
Local recurrence is common; malignant transformation is extremely rare

Essential features

Characteristic radiologic appearance; i.e. eccentric lytic lesion with sharp, sclerosed and scalloped intramedullary edges
Histologically, zonal architecture comprised of lobules of myxoid to chondroid tissue with intervening spindle and multinucleated giant cells, showing variable coarse calcifications
Complete surgical resection is the treatment of choice, with chances of recurrence following simple curettage but no potential for distant metastasis

ICD coding

ICD-O: 9241/0 - chondromyxoid fibroma
ICD-11: 2E82.Z & XH89S0 - benign chondrogenic tumors, site unspecified and chondromyxoid fibroma

Epidemiology

Rare, benign chondroid tumor
Wide age range but mostly arises in young adults in second and third decades of life and more commonly in males (J Bone Joint Surg Am 1983;65:198, Hum Pathol 1998;29:438)

Sites

Most common:
- Long tubular bones; most frequently distal femur and proximal tibia
Less common:
- Small bones of hands and feet, pelvis, sacrum, spine, et cetera (J Cytol 2018;35:67, Surg Neurol Int 2016;7:S370)
- Skull bones (Cureus 2019;11:e5841, Indian J Ophthalmol 2019;67:2110, Acta Oncol 2005;44:545)

Pathophysiology

Upregulation of glutamate receptor gene GRM1 coding region of chromosome 6 through recombination with several partner genes in up to 90% of cases (Nat Genet 2014;46:474)

Etiology

Unknown

Diagrams / tables

Contributed by Qurratulain Chundriger, M.B.B.S.

Drawing showing histology

Clinical features

Long bones: present with pain, often of long duration (Korean J Radiol 2011;12:761)
Flat bones and small bones: swelling sometimes accompanied by pain (Iran J Pathol 2016;11:272, J Clin Diagn Res 2016;10:ED01)

Diagnosis

Requires integration of radiological and histopathological findings
Diagnosis can be challenging on a small biopsy specimen (e.g. cytology or needle core)

Radiology description

Long bones:
- Eccentric, lytic, radiolucent metaphyseal lesions with well demarcated sclerosed and scalloped intramedullary edges; rarely crosses a growth plate
- Associated secondary aneurysmal bone cysts may be seen
- Internal mineralization is better seen with CT as compared with conventional radiology (Br J Radiol 2016;89:20160088)
- CT shows isointense or hypointensity on T1 images, heterogeneous hyperintensity on T2 images (Br J Radiol 2016;89:20160088, World J Surg Oncol 2014;12:283)
- Increased uptake on fluorodeoxyglucose PET (Clin Nucl Med 2009;34:15)
Small and flat bones:
- Lytic lesions are expansile, loculated and locally destructive
- Lesions in ribs may appear fusiform with thinned out overlying cortices (J Clin Diagn Res 2015;9:XD04)
- Sacral and spinal lesions may appear malignant radiologically with cortical breaks and extension into adjacent soft tissue and spinal canal (Surg Neurol Int 2016;7:S370, Br J Radiol 2016;89:20160088)

Radiology images

Contributed by Mark R. Wick, M.D. and Nasir Ud Din, M.B.B.S.

Metatarsal Xray

Femur Xray

Tibia Xray

Proximal femur

Distal tibia

Proximal tibia

Distal tibia

Metatarsal

Images hosted on other servers:

Nasal mass

Sternum

Sellar lesion

Radius

Rib

Sacrum

Metatarsal

Prognostic factors

Around 15% cases may recur, mostly following simple curettage rather than total resection (World J Surg Oncol 2014;12:283)
Malignant transformation can occur after radiation therapy

Case reports

13 year old girl with painful knee swelling (Tunis Med 2017;95:999)
16 year old boy with headache, diplopia and dizziness (Medicine (Baltimore) 2017;96:e9049)
47 year old woman with swelling of left side of face (J Educ Health Promot 2017;6:78)
63 year old woman with chest pain and swelling (Tex Heart Inst J 2015;42:400)

Treatment

En bloc resection of the tumor is the treatment of choice
In cases where complete resection is not possible, radiation following surgery may be helpful (Acta Oncol 2005;44:545)
Instances of complete tumor disappearance following radiofrequency ablation have been described (J Orthop Surg (Hong Kong) 2017;25:2309499017720830)

Clinical images

Images hosted on other servers:

Lesion in mandible

Orbital tumor with globe displacement

Gross description

Lobulated tumor mass with intact periosteum
Cut surface is firm, glistening with variable myxoid areas (J Clin Diagn Res 2015;9:XD04)
Calcifications may not be seen grossly

Gross images

Images hosted on other servers:

Orbital tumor resection specimen

Resection of rib tumor

Microscopic (histologic) description

Lobulated architecture; lobules separated by mononuclear spindle cells and admixed multinucleated giant cells
Lobules have hypocellular centers and hypercellular periphery
Variably myxoid to chondroid stroma, representing various stages of cartilaginous development (Hum Pathol 1998;29:438)
Lobules have stellate cells in a myxoid background and reside in lacunae in chondroid areas (Am J Clin Pathol 2001;116:271)
Cells have variable pink cytoplasm, bipolar to multipolar cytoplasmic extensions and oval to spindled nuclei
Marked nuclear pleomorphism with nucleoli may be seen in some cases
Periphery of lobules show spindle shaped fibroblast-like cells and scattered multinucleated osteoclast-like giant cells
Low mitotic rate
Coarse calcifications may be seen in the stroma, particularly in tumors arising in older age group and unusual sites (Skeletal Radiol 1998;27:559)
Hemosiderin deposition and lymphocytes may be seen
Necrosis, cystic change or degenerative changes are rare
10% of cases may show associated areas of aneurysmal bone cyst-like appearance (Hum Pathol 1998;29:438)

Microscopic (histologic) images

Contributed by Nasir Ud Din, M.B.B.S.

Confluent nodules with giant cells

Well defined nodular growth

Fibroblastic population

Peripheral giant cell proliferation

Stellate mesenchymal cells in nodules

Adjacent ABC-like areas

Chondroid differentiation

Well developed chondroid areas

Calcifications

Cytology description

Smears are moderately cellular, having fragments of fibrillary myxochondroid tissue, which stains metachromatically (Diagn Cytopathol 2013;41:904)
Fragments of spindle cells and variable numbers of osteoclast-like giant cells are seen (Iran J Pathol 2016;11:272)
Nuclear atypia may be variable and result in malignant interpretation
Calcification may not be seen in cytology smears

Cytology images

Images hosted on other servers:

FNA of metatarsal lesion

FNA of lytic lesion in femur

FNA of metatarsal head lesion

Positive stains

Chondromyxoid fibroma does not require immunohistochemistry for diagnosis
S100 and SOX9: positive in the cells within chondroid lobules (Hum Pathol 1989;20:952)
SMA: spindle cells at the periphery of lobules may show some degree of positivity

Negative stains

Electron microscopy description

Cells show cytoplasmic processes, intracytoplasmic glycogen and thickening of the nuclear membrane

Molecular / cytogenetics description

Not required for reaching diagnosis
GRM1 upregulation is highly specific for chondromyxoid fibroma

Videos

Cartilage forming tumors

Sample pathology report

Left knee and proximal tibia, curettage:
- Benign cartilaginous tumor with features favoring chondromyxoid fibroma (see comment)
- Comment: Correlation with radiological findings is essential.

Differential diagnosis

Central chondrosarcoma:
- Radiographically destructive, osteolytic lesion with invasion into adjacent bone and soft tissue, moth eaten appearance and foci of calcifications
- Histologically infiltrative lobules of cartilage with variable degree of cellularity and nuclear atypia
- Characterized by IDH mutations
Chondroblastoma:
- Arises mostly in young patients with immature skeleton
- Epiphyseal location is characteristic
- Islands of mononuclear cells with distinct cell borders, characteristic grooved nuclei; scattered cells may appear epithelioid
- Chicken wire-like calcifications are characteristic
- Harbors mutations of H3.3 (H3F3B gene) on chromosome 17
Osteochondromyxoma:
- Extremely rare chondroid and osteoid matrix producing benign myxoid tumor, occurring in association with Carney complex
- Tumor arises in the diaphysis of radius and tibia and nasal bone
- Variably cellular tumor of polygonal bipolar to stellate cells arranged in sheets and lobules along with osteoid and chondroid matrix present in myxoid stroma
- Lacks GRM1 upregulation and other chromosome 6 aberrations; instead harbors mutations of PRKAR1A at chromosome 17
Aneurysmal bone cyst:
- Lytic expansile lesion on radiology with variable fluid levels on MRI
- Composed of cystic blood filled spaces lined by osteoclast-like giant cells
- Solid areas show spindle cell proliferation with blue bone formation
- May be associated morphological finding in a number of benign and malignant bone and cartilaginous tumors
Giant cell tumor:
- Arises in epiphyses of long bones in adults
- Uniform distribution of osteoclast type giant cells among mononuclear cells
- Shows positive staining for RUNX2, SATB2, H3.3 (G34W)
- Excellent response to denosumab (RUNX ligand inhibitor)

Additional references

Int J Surg Pathol 2019;27:352, J Int Adv Otol 2020;16:117

Board review style question #1

A 25 year old woman presented with painful swelling of the right knee. Radiology shows a lytic lesion with sclerotic intramedullary margins in the metaphysis of proximal fibula. En bloc resection of tumor was done and microscopy showed the above picture. Which of the statements regarding this entity is true?

Denosumab is a newly developed drug for nonsurgical treatment
Diagnosis does not require correlation with radiology
Most cases of this tumor present clinically as painless masses
Presence of adjacent aneurysmal bone cyst-like areas is unlikely
This tumor shows various stages of cartilaginous development

Board review style answer #1

E. This tumor shows various stages of cartilaginous development. The photomicrograph shows a tumor comprised of lobules of myxoid to chondroid appearance with adjacent mononuclear cell population and some osteoclast-like giant cells. These findings are characteristic of chondromyxoid fibroma, which is also suggested by clinical and radiological appearances. The myxochondroid lobules of chondromyxoid fibroma represent various stages of cartilaginous development, from myxoid mesenchyme to well developed hyaline cartilage. Diagnosis always requires radiological correlation, which shows characteristic eccentric lytic lesion in the metaphyseal region of long bones. Painful mass is a common clinical presentation. Adjacent aneurysmal bone cyst-like areas may be seen in up to 10% of cases. Denosumab is a RUNX ligand inhibitor, recently developed for the treatment of giant cell tumor of bone.

Comment Here

Reference: Chondromyxoid fibroma

Board review style question #2

Which of the following genetic alterations is characteristic of chondromyxoid fibroma?

GRM1 upregulation
H3F3B mutation
IDH1 mutation
PRKAR1A mutation
USP6 rearrangements

Board review style answer #2

A. GRM1 upregulation. USP6 rearrangements are seen in aneurysmal bone cysts. IDH1 mutations are characteristic of chondrosarcoma. H3F3B is mutated in chondroblastoma and PRKAR1A mutations are seen in osteochondromyxoma in the setting of Carney complex.

Comment Here

Reference: Chondromyxoid fibroma

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