Bone, cartilage, joint pathology Flashcards
Knee joint.
Dx?
Key features?
XR features?
Synovial chondromatosis
Features: Synovial chondromatosis has a well-defined, multinodular architecture, characterized by discrete nodules of hyaline cartilage within subsynovial tissue. The chondrocytes are arranged in small clusters. Matrix usu hyaline but can be myxoid. Can undergo endochondral ossification.
XR: periarticular punctate calcifications
Erdheim Chester disease
What is it?
Common genetic mutation
Key histo features
IHC
Rare, clonal histiocytosis with frequent multiorgan involvement
Also known as polyostotic sclerosing histiocytosis
Skeletal involvement in almost all (> 95%) cases, most often in the long bones of the lower extremities
Correlation of clinical features, histology and radiological findings are essential for diagnosis (Blood 2016;127:2672)
Systemic disease with frequent involvement of bone, retroperitoneum (hairy kidney, coated aorta), CNS and lung
BRAF V600E mutation in > 50% of cases
Soft tissue infiltrate of bland appearing histiocytes characterized by abundant foamy (xanthomatous) cytoplasm with surrounding fibrosis
Touton giant cells are frequently present
Associated lymphoplasmacytic infiltrate is sparse
Erdheim-Chester disease may be a component of mixed histiocytosis with Langerhans cell histiocytosis or Rosai-Dorfman disease
osteoid osteoma vs osteoblastoma
distinguishing clinical and radiological features?
gene rearrangements in osteoid ostoma and osteoblastoma
FOS (and less so FOS-B) gene rearrangements.
FOS gene rearrangements also found in epithelioid haemangioms
osteosarcoma
RF for primary vs secondary osteosarcoma
Anatomically, how can osteosarcoma be described and which are high vs low grade
hereditary condition a/w multiple osteochondromas?
Mode of inheritance?
Multiple hereditary exostosis.
Autosomal dominant.
multiple endchondromas, syndromic association?
Ollier’s syndrome (not inherited)
Maxillary incidental lesion:
Dx?
Essential dx features?
Ddx:
Osteoma
Essential: bone tumour with compatible imaging; tumour arises on the surface of bone or within the medullary cavity; tumour composed of lamellar/cortical-type bone.
osteoblastoma/osteoid osteoma; osteosarcoma
Gene rearrangements in osteoid osteoma; osteoblastoma?
FOS gene rearrangement (not necessary for diagnosis) may be found in osteoid osteoma, but it can also be found in osteoblastomas and epithelioid haemangiomas
osteoid osteoma vs osteoblastoma?
describe an approach to bone and cartilage forming tumours? (hint: 4 x4)
How could you distinguish LG central osteosarcoma from fibrous dysplasia?
FISH for CDK4 or MDM2 amplification
Gene rearrangement in ABC?
Translocation involving the USP6 gene
syndromes associated with increased risk of chondrosarcoma
Ollier disease and Maffucci syndrome
what is the size cut-off between osteochondroma and chondrosarcoma?
2cm
syndromes associated with:
Enchondromas
Osteochondromas
Enchondromas: Ollier’s disease and maffucci syndrome
Ollier disease: multiple enchondromas in the appendicular skeleton in an asymmetric manner
Typically in short and long bones of the limbs; epiphyseal tumors can prevent normal bone growth in young patients
Maffucci syndrome
Multiple enchondromas in association with soft tissue and visceral hemangiomas and lymphangiomas
Osteochondroma: Multiple hereditary exostosis (AD) /hereditary multiple osteochondroma syndrome. Multiple osteochondroma syndrome is an AD condition caused by mutation sin EXT1 or EXT2.
mesenchymal chondrosarcoma: key features, demographic, location and molecular
Key features:
- primitive/PD round cells
-staghorn vessels
-WD islands hyaline cartilage
Age: 2nd-3rd decade
Location: craniofascial 50%
Molecular: HEY1-NCOA2 rearrangement
Enchondromas - key features + location?
Disease/syndromic associations?
Benign hyaline cartilage neoplasm of medullary bone. Most solitary. Lobular, cell poor, hyaline cartilage -> demarcated by zone of reactive bone formation.
Site: Hands and feet (uncommon for ACT).
Nonhereditary Ollier disease and Maffucci syndrome (latter = multiple enchondromas + spindle cell haemangioma).
synovium shoulder joint.
Dx?
How to prove?
pseudogout
Weakly anisotropic rhomboid to rod shaped crystals demonstrating positive birefringence under polarized light
Diagnosis requires demonstration of calcium pyrophosphate crystals in synovial fluid or biopsy material
chondroblastoma key features and IHC?
skeletally immature, epiphyeal/apophyseal location
ovoid, polygonal cells with grooved nuclei
islands of chondroid matrix
Giant cells
chicken wire calcifications
IHC:
antibody against H3.3B (H3F3B) p.Lys36Met (K36M) shows diffuse nuclear expression in > 96% of the cases
genetic mutation in osteoid osteoma and osteoblastoma?
rearrangements of the FOS gene
which syndromes are a/w markedly increased risk of chondrosarcomas?
Ollier disease and Maffucci syndrome
Subtypes of conventional osteosarcoma ? (7)
Osteoblastic
Giant cell rich
Chondroblastic
Fibroblastic
Telangiectatic
Small cell variant
Epithelioid
