Bone Flashcards
What IHC can distinguish mesenchymal chondrosarcoma from small cell osteosarcoma, or EWING sarcoma if cartilage is not present?
SOX9 - + in mesenchymal chondrosarcoma and neg in others
Describe the histology of mesenchymal chondrosarcoma
Also the usual age and locations
Finally, important IHC markers and how it can distinguish it from differentials
Sheets of small round blue cells (oval, or spindled) scattered nodules of moderately cellular hyaline cartilage (can ossify).
There is hemangiopericytoma like vasculature throughout the small cell component
Usually between 10 and 40 years of age
Jaw (craniofacial bones), vertebra, and ribs are the MOST COMMON SITES
Followed by extremities. Some also happen in soft tissue
Sox 9 + (EWS will be be sox9 - and FLI1 +)
Describe Ollier disease and Maffucci disease
Ollier disease = enchondromatosis
Non familial have multiple enchondromas, usually unilateral - Higher risk of malignant transformation
And some associated risk for other malignancies
Maffuci - non familial, multiple chondroid lesions and soft tissue HEMANGIOMAs, Associated with very HIGH incidence of MALIGNANCY in skeleton and visceral organs
Describe Nonossifying fibroma (NOF) and BFH of bone:
age, site, histology
NOF is very common, in young children, at the metaphysis of long bones
called fibrous cortical defect if limited to cortex, NOF extends into medullary cavity
Bland, storiform spindle cell proliferation with multi-nucleated cells, hemosiderin, and foam cells
BFH of bone is rare, and is NON-METAPHYSEAL, and occurs in people > 20 usually - histologically identical to NOF
What is the translocation associated with ABC?
t(16:17) CDH11 - USP6 translocation
what are the key histologic differences between giant cell tumor and chondroblastoma?
Similar histology, but GCT has a SYNCITIAL growth of round cells with nuclei identical to those in the giant cells
Chrondroblastoma has sheet like growth (like GCT) but the cells have WELL-DEFINED cell borders and the nuclei of the mononuclear cells are different than the giant cells. The nuclei often have small nucleoli and longitudinal grooves. Also of course, there are islands of chondroid material.
Also there are characteristic CHICKEN WIRE calcifications in vasculature surrounding islands of cells
Describe the Carney Triad: Neoplasms, age, gender
Young Females,
Pulmonary chondromas
GIST
paraganglioma
Describe parosteal osteosarcoma
nswer:
Low grade osteosarcoma on the surface of bone (most common surface osteosarcoma) that mimics osteochondroma in that it has what looks like a cartilage cap (but it it a little too cellular, and there is often a low grade spindle cell sarcoma on top of the cartilage)
Also, you see low grade spindle cells filling the spaces between many bony trabeculae made of woven bone (instead of marrow)
What is the differential for giant cell rich neoplasms in bone and their main features?
Giant cell tumor - epiphysis and metaphysis of long tubular bones, ages 20s to 50s
syncitial growth of mononuclear neoplastic cells with nuclei identical to those of giant cells, which can contain > 50 nuclei and are EVENLY distributed throughout the tumor.
Mononuclear cells are p63 +!!
Chondroblastoma - centered in epiphysis in skeletally immature patients, the mononuclear cells have distinct cell borders and nuclei DIFFERENT from those of giant cells (longitudinal grooves and small nucleoli) , occasional chondroid areas and CHICKEN wire calcificaiton
mononuclear cells are p63-!
ABC - in metaphysis of long bones, if solid can be very similar to GCT, but again the mononuclear cells are spindled and NOT identical to nuclei in giant cells also the t(16:17) - CDH11 - USP6 is present
immature osteoid present, foam cells
Non-ossifying fibroma / BFH
Has spindled cells (GCT can also), but classic areas of GCT are absent
Giant cell reparative granuloma - giant cells are around hge, NOT evenly distributed, background proliferating cells are spindle shaped
p63 is positive also
Brown tumor - histologicall identical to Giant cell reparative granuloma, except that it has more lobulated architecture, and the UI bone shows osteoclasts boring through trabeculae (dissecting osteitis)
Chondromyxoid fibroma - can have peripheral occasional giant cells
Describe Epithelioid hemangioma
It is analogous to angiolymphoid hyperplasia with eosinophils in the skin, but when it occurs in bone, there is not as much lymphoid hyperplasia or eosinophils.
You have very epithelioid endothelial cells with grooved nuclei with finely distributed chromatin and abundant eosinophilic cytoplasm - some intracellular lumina also
Is locally aggresive, does not metastasize.
