Summary of cytological and radiological findings in bone lesions.
Lesion
Cytology
Radiology
Osteoid Osteoma
Sparse population of osteoblasts with
sprinkling of fibrocytes and osteoclasts.
Osteoblasts show none of the changes of
Dense cortical sclerosis with surrounding
radiolucent nidus. If centre is also ossified then
appears “target like”.
osteosarcoma, which is an important
negative finding.
Osteoblastoma
Osteoblasts like cells, singly or in groups
A lytic well circumscribed oval or round
defect confined by a periosteal shell of
or in rows.
Multi nucleated osteoclast like cells.
reactive bone.
Cluster of spindle cells.
Osteosarcoma
 Pleomorphic spindle and rounded cells.
In most cases, mixed lytic/blastic lesion.
 Tumor cells resembling Osteoblasts.
The radio density is “cumulus cloud like”
 Multinucleated tumor cells and
with tumor invasion into soft tissue. Osteoblastic
atypical mitotic figures.
 Presence of Osteoid (clumps of
amorphous
eosinophilic material)
variety presents with sunburst configuration due
to periosteal reaction or “Codman’s
triangle” due to periosteal elevation.
CT/MRI helpful in delineating the extent of
tumor and Tm99 scan for predicting “skip
metastasis” and multicentricity.
Parosteal
 All the above features
Mineralized mass attached to the cortex
osteosarcoma
Different in location
With a broad base. CT/MRI useful
in evaluating the extent of medullary
involvement.
Chondroma
 Predominantly cartilaginous tissue
fragments.
Well- marginated tumors from radiolucent
to heavily mineralized. Mineralized pattern
 Cells in lacunar spaces within fragments. is punctuate, flocculent or has ring and arc
 Abundant chondromyxoid ground substance.pattern.
Osteochondroma
Character Characteristic feature is a
Projection of the cortex in continuity
with the underlying bone. Irregular
calcification is seen. Irregular
calcification is seen. A flocculent
calcification raises the suspicion of
malignant transformation. CT/MRI- continuity of
marrow spaces into the lesion.
Chondroblastoma
 Fragments of chondroid matrix
Typically lytic, centrally or eccentrically placed,
 Multi nucleated osteoclast-like cells.
relatively small (3-6 cms) lesions and are
 Mononuclear, rounded cells with distinct sharply demarcated with or without a thin
cell borders and rounded nuclei.
sclerotic border.
Chondromyxoid
Myxoid background substance
Metaphyseal, eccentric area of lysis with a
fibroma
 Chondroid fragments.
sclerotic border, cortical thinning and
 Spindle-shaped fibroblast-like cells,
extension to the subchondral plate. On
single or in clusters.
Chondrosarcoma
occasion it has a trabeculated “soap
 Osteoclast-like giant cells.
bubble appearance”
 Predominantly tissue fragments in low
Fusiform Fusiform expansion and
grade, single cells may predominate
thickening of cortical bone. It
in high-grade sarcomas.
presents as radiolucency
 Abundant eosinophilic, vacuolated
cytoplasm.
 Chondromyxoid material
with variably distributed punctate
or ring like opacities
(mineralization). CT helpful in
demonstrating matrix calcification.
Mesenchymal
Chondrosarcoma
 All the above with presence of
mesenchymal elements.
Primarily lytic and destructive with
poor margins, not significantly differing
from ordinary chondrosarcoma. Mottled
calcification is sometimes prominent.
Expansion of the bone and cortical
destruction or cortical break through
with extra-osseous extension into soft tissue is
common.
Osteoclastoma
 Abundant material
An expanding and eccentric area of
 Dispersed cells and cohesive cell clusters lysis with a sclerotic border, cortical
A double cell population: mononuclear
thinning and extension to the subchondral
spindle cells and giant cells of osteoclastic plate. On occasion it has a trabeculated
“soap bubble appearance”
type.
 Giant cells are attached to the
periphery of the clustered spindle cells.
Ewing’s sarcoma
 Dissociated cells and clusters of cohesive A well defined osteolytic lesion
cells
 Two cell types: large pale cells
with abundant vacuolated cytoplasm
involving the diaphysis is the most
common feature. Permeative or moth
eaten bone destruction often associated
cells with scanty cytoplasmwith “onion skin” like multi layered
periosteal reaction is characteristics.
 Abundant Cytoplasmic glycogen
and small dark
 Occasionally rosette-like structures
Lymphoma


A monotonous population of small
Quite variable X-ray findings and
lymphoid cells to varying number of
somewhat non-specific. The findings can range
prolymphocytes.
from extensive lytic and sclerotic lesions to the
Characteristics coarse granular nuclear
variable sclerosis with cortex destruction.

chromatin (“grumele”); nucleoli.
In absence of cortical involvement the
Reed-Sternberg cells, Hodgkin cells
marrow destruction may not be obvious
and variable number of eosinophils,
on plain X-ray. Bone scan and MRI
plasma cells and histiocytes.
very useful in such settings.
Plasma cells
 Many plasma cells
Myeloma
 Single cell presentation
and are not surrounded by a sclerotic
 Variable cell differentiation
zone. CT/MRI may discover a very subtle
Lesions are lytic, sharply demarcated
small lesion not visible on plain X-ray.
Haemangioma
 Limited role of cytology in diagnosis
Well demarcated multiple cystic defects
of haemangioma as blood elements fill
that frequently contain coarse trabeculations
up the field.
(often resulting in “polka dot pattern) and
striations.
Fibrosarcoma
 Well differentiated:
Appears on X-ray as a destructive
Cells are fusiform with elongated nuclei, geographic lesion, but may have ill defined
without any of the pleomorphism evident permeative “moth eaten” appearance
in poorly differentiated fibrosarcoma
 Poorly differentiated:
Fusiform cells with elongated or ovoid
Nuclei but cells with rounded, polyhedral
or stellate shapes are also seen,
with cortical destruction and frequent soft tissue
extension.
together with giant tumor cells with
large or multiple nuclei
Chordoma
 Abundant myxoid ground substance
Solitary, central, lytic, destructive lesions
 Physaliphorus cells
of the axial skeleton. Intra-tumoral
 Clusters of epithelial like cells.
calcification is seen particular in sacral tumors.
 Pleomorphic tumor cells in some tumors.
Simple bone
cyst
 Scanty population of rounded or fusiform Metaphysio-diaphyseal lucency, extending up
cells similar to as in non-ossifying fibroma.to epiphyseal plate, with little or no expansion
 Random osteoclasts and osteoblasts
may be seen
Aneurysmal bone
cyst
 Smears are heavily blood stained
Lytic, eccentric, expansile mass with well
defined margins. Most tumors contain a thin
similar to as in non-ossifying fibroma.
shell of sub-periosteal reactive bone. CT/MRI
a scattering of osteoblasts
Dysplasia
but is intact unless pathological fracture occurs.
and contain fusiform and rounded cells
 Fair number of osteoclasts and
Fibrous
of bone. The cortex is usually eroded and thin,
 Sparse population of well-
show internal septa and characteristic fluid-fluid
level.
Non-aggressive geographic lesion with a
differentiated fibrocytic looking cells
ground glass matrix. There is no soft tissue
with mature ovoid or elongated nuclei.
extension and a periosteal reaction is usually
not seen.
Langerhans Cell
Histiocytosis
Large histiocytes with vesicular nuclei
X-rays generally show a purely lytic, well-
of irregular shape, sometimes binucleated. demarcated lesion, usually associated with
 Variable number of eosinophils
thick periosteal new bone formation. Skull
 Giant cells of histiocytic type.
lesions are sometimes described as “hole
in a hole”. Vertebral involvement produces
a “vertebra plana”