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Radiological Signs in Bone Tumours

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Radiological Signs in Bone Tumours

Comprehensive guide to radiological signs in bone tumours covering aggressive vs non-aggressive features, periosteal reactions, matrix mineralisation, tumour location, and staging imaging for fellowship exam preparation.

Very High Yield
complete
Reviewed: 2026-03-11By OrthoVellum Medical Education Team

Reviewed by OrthoVellum Editorial Team

Orthopaedic clinicians and medical editors • Published by OrthoVellum Medical Education Team

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High Yield Overview

Radiological Signs in Bone Tumours

Aggressive vs Non-Aggressive Features & Pattern Recognition

LodwickClassification: geographic, moth-eaten, permeative
CodmanTriangle: lifted periosteum from aggressive tumour
SunburstSpiculated periosteal reaction = aggressive (osteosarcoma)
Onion skinLamellated periosteal reaction = aggressive (Ewing)
MRIGold standard for local staging (intramedullary and soft tissue extent)
CT chestESSENTIAL for pulmonary metastasis staging
LocationTumour location within bone is a key diagnostic clue
MatrixCalcification pattern: chondroid (rings/arcs) vs osteoid (cloud-like)

Lodwick Classification for Bone Tumour Aggressiveness

Type IA: Geographic, well-defined sclerotic margin = benign (NOF, enchondroma, SBC)

Type IB: Geographic, well-defined NO sclerotic margin = low-grade malignant or aggressive benign

Type IC: Geographic, ill-defined margin = intermediate aggressiveness

Type II: Moth-eaten (multiple small lytic areas) = moderately aggressive malignancy

Type III: Permeative (cortical destruction, no defined margin) = highly aggressive malignancy

Key: The more well-defined and sclerotic the margin, the less aggressive the lesion

Critical Must-Knows

  • Lodwick classification determines aggressiveness: geographic (I) = slow-growing, moth-eaten (II) = moderately aggressive, permeative (III) = highly aggressive.
  • Codman triangle: periosteum lifted by tumour with reactive bone at the margin — does NOT represent tumour tissue itself (do not biopsy the Codman triangle).
  • Matrix mineralisation pattern: chondroid (rings and arcs, stippled) vs osteoid (cloud-like, dense) — helps narrow the differential.
  • Tumour location within the bone: epiphysis (GCT, chondroblastoma), metaphysis (osteosarcoma, chondrosarcoma), diaphysis (Ewing, lymphoma, fibrous dysplasia).
  • MRI is essential for local staging: intramedullary extent, soft tissue mass, skip lesions, neurovascular involvement.

Examiner's Pearls

  • "
    GCT: subarticular (epiphysis touching articular surface), eccentric, lytic, NO matrix mineralisation. Peak age 20-40. Knee region most common.
  • "
    Osteosarcoma: metaphyseal, mixed lytic/scite, cloud-like osteoid matrix, Codman triangle, sunburst periosteal reaction. Peak age 10-25.
  • "
    Ewing sarcoma: diaphyseal in children, permeative, lamellated (onion-skin) periosteal reaction, large soft tissue mass. Peak age 5-15.
  • "
    Chondrosarcoma: medullary, rings and arcs calcification, endosteal scalloping more than two-thirds cortex, NO periosteal reaction (slow-growing).
  • "
    Metastases are the MOST COMMON malignant bone tumour in adults over 40 (primary malignant tumours are rare at this age).

Exam Warning

Bone tumour radiological assessment is one of the highest-yield examination topics. You must be able to: classify aggressiveness using Lodwick criteria, identify periosteal reaction patterns, recognise matrix mineralisation, describe tumour location within bone, and outline the staging imaging pathway. Classic traps: not considering metastases as the most common malignant bone tumour in adults over 40, and confusing the Codman triangle with tumour tissue (it is reactive periosteum — do not biopsy it).

Mnemonic

MAPLESBone Tumour Aggressiveness Assessment

M
Margin (Lodwick classification)
Geographic with sclerotic rim (IA) = benign. Geographic without sclerosis (IB-IC) = low-grade. Moth-eaten (II) = moderate. Permeative (III) = aggressive
A
Age of patient
Under 5: neuroblastoma, leukaemia, Langerhans cell histiocytosis. 5-25: Ewing, osteosarcoma, Ewing. 20-40: GCT, chondrosarcoma. Over 40: METASTASES, myeloma
P
Periosteal reaction
Solid/thick = slow-growing (benign). Lamellated (onion-skin) = moderately aggressive (Ewing). Sunburst/spiculated = aggressive (osteosarcoma). Codman triangle = aggressive
L
Location within bone
Epiphysis: GCT, chondroblastoma. Metaphysis: osteosarcoma, chondrosarcoma, SBC, ABC. Diaphysis: Ewing, fibrous dysplasia, lymphoma
E
Expansion and soft tissue mass
Expanded shell of bone = slow-growing (ABC, GCT). Cortical breakthrough with soft tissue mass = aggressive (osteosarcoma, Ewing)
S
Struck-through matrix (mineralisation)
Chondroid matrix: rings and arcs, stippled (enchondroma, chondrosarcoma). Osteoid matrix: cloud-like, dense (osteosarcoma, osteoid osteoma)

Memory Hook:MAPLES: the systematic approach to bone tumour radiograph assessment — Margin, Age, Periosteal reaction, Location, Expansion, Struck-through matrix.

Mnemonic

SCOLHPeriosteal Reaction Patterns

S
Sunburst/spiculated
Periosteal new bone radiates outward perpendicular to the cortex. Most aggressive pattern. Classic for osteosarcoma. Indicates rapid tumour growth through cortex
C
Codman triangle
Triangular area of lifted periosteum at tumour margin. NOT tumour tissue — it is reactive bone at the edge where periosteum is elevated. Do NOT biopsy the triangle
O
Onion-skin (lamellated)
Multiple layers of periosteal new bone. Moderately aggressive. Classic for Ewing sarcoma. Each layer represents a cycle of tumour expansion and periosteal reaction
L
Lobulated/thick solid
Thick, uniform layer of periosteal new bone. Non-aggressive (slow-growing). Seen with benign tumours (osteoid osteoma), healing fractures, chronic infection
H
Hair-on-end
Fine perpendicular spicules radiating from cortex. Seen in thalassaemia (marrow expansion), haemangioma (skull), and aggressive tumours

Memory Hook:SCOLH: periosteal reactions from most aggressive to least — Sunburst, Codman, Onion-skin, Lobulated, Hair-on-end.

Mnemonic

EpiMeDiCommon Tumours by Location in Bone

E
Epiphysis (GCT, Chondroblastoma)
GCT: subarticular, eccentric, lytic, no matrix. Age 20-40. Chondroblastoma: in UNFUSED epiphysis, age 10-25, stippled calcification
M
Metaphysis (Osteosarcoma, SBC, ABC, Chondrosarcoma)
Osteosarcoma: cloud-like osteoid, sunburst. SBC: central, fluid-filled. ABC: eccentric, expanded, fluid-fluid levels on MRI. Chondrosarcoma: rings/arcs matrix
Di
Diaphysis (Ewing, Fibrous Dysplasia, Lymphoma)
Ewing: permeative, lamellated, large soft tissue mass. Fibrous dysplasia: ground-glass matrix, shepherd's crook deformity. Lymphoma: permeative, age more than 40

Memory Hook:EpiMeDi: Epiphysis-Metaphysis-Diaphysis — know which tumours favour which location.

Overview

Radiological assessment of bone tumours requires a systematic approach that integrates multiple imaging features to narrow the differential diagnosis and determine aggressiveness. The key principles are: (1) assess the margin of the lesion (Lodwick classification), (2) evaluate the periosteal reaction pattern, (3) identify the matrix mineralisation, (4) note the location within the bone and the skeleton, and (5) consider the patient's age. These five features, assessed together, significantly narrow the differential diagnosis and guide further investigation.

The Lodwick Classification

The single most important radiographic feature is the MARGIN of the lesion, classified by Lodwick: Type IA — geographic destruction with a well-defined sclerotic rim. This is the classic appearance of benign lesions (non-ossifying fibroma, enchondroma, simple bone cyst). The sclerotic rim indicates the host bone is keeping pace with the lesion's growth. Type IB — geographic destruction with a well-defined margin but NO sclerotic rim. This suggests a low-grade malignancy or aggressive benign lesion (GCT, chondrosarcoma). Type IC — geographic with an ill-defined margin. Intermediate aggressiveness. Type II — moth-eaten pattern (multiple small lytic areas without defined margins). Moderately aggressive malignancy. Type III — permeative pattern (cortical destruction without any defined lesion margin). Highly aggressive — Ewing sarcoma, osteosarcoma, lymphoma, metastases.

Staging Imaging Protocol

When a bone tumour is suspected: (1) Plain radiograph: ALWAYS the first investigation. Provides the most diagnostic information for pattern recognition. (2) MRI of the ENTIRE involved bone (including the joint above and below): shows intramedullary extent, soft tissue mass size, skip lesions, and neurovascular relationship. Essential for surgical planning. (3) CT chest: MUST be performed for pulmonary metastasis staging (the lungs are the most common site of metastasis for primary bone tumours). (4) Bone scan or PET-CT: for skeletal staging (detecting other skeletal lesions). (5) CT-guided biopsy: for histological diagnosis. CRITICAL: the biopsy tract must be planned with the surgeon who will perform the definitive surgery — a poorly placed biopsy contaminates tissue planes and may compromise limb salvage surgery.

Clinical Imaging

Imaging Gallery

Codman triangle demonstrating lifted periosteum from aggressive bone tumour
Click to expand
Codman triangle: a triangular area of lifted periosteum at the margin of an aggressive bone tumour. The triangular reactive bone at the edge is NOT tumour tissue — it represents the host's attempt to contain the tumour with new periosteal bone formation. CRITICAL: do NOT biopsy the Codman triangle.Credit: Open-i (NIH) (Open Access (CC BY))
Giant cell tumour demonstrating subarticular lytic lesion
Click to expand
Giant cell tumour (GCT) of the distal femur demonstrating the classic radiographic features: subarticular (epiphyseal) location extending to the articular surface, eccentric position, well-defined lytic lesion without sclerotic margin (Lodwick type IB), and NO matrix mineralisation. Peak age 20-40 years.Credit: Open-i (NIH) (Open Access (CC BY))

Systematic Approach

Bone Tumour Pattern Recognition

Classic Bone Tumour Patterns by Diagnosis

TumourRadiographic FeaturesKey Distinguishing Feature
OsteosarcomaMetaphyseal, mixed lytic/sclerotic, cloud-like osteoid matrix, Codman triangle, sunburst periosteal reactionCloud-like mineralisation + aggressive periosteal reaction. Peak age 10-25. Around knee (60%)
Ewing sarcomaDiaphyseal (in children), permeative, lamellated (onion-skin) periosteal reaction, LARGE soft tissue massPermeative destruction + large soft tissue mass disproportionate to bone lesion. Peak age 5-15
ChondrosarcomaMedullary, rings and arcs calcification, endosteal scalloping more than two-thirds cortex, NO periosteal reactionRings and arcs matrix + endosteal scalloping. Peak age 40-60. Slow-growing, rarely metastasises
Giant cell tumourSubarticular (epiphyseal), eccentric, well-defined lytic, NO matrix, NO sclerotic rim (Lodwick IB)Epiphyseal location touching articular surface in CLOSED physis. Peak age 20-40. Knee region
Simple bone cyst (SBC)Central metaphyseal, well-defined lytic, thin sclerotic rim, fallen fragment sign (pathological fracture)Central location. Fallen fragment sign = fragment falls to dependent portion of cyst. Age 5-15
Non-ossifying fibroma (NOF)Eccentric metaphyseal, well-defined scalloped sclerotic rim, cortically based (bubbly)Most common incidental bone lesion. Lodwick IA. Cortical thinning without breach. Age 10-20. No treatment
EnchondromaCentral, well-defined lytic with rings and arcs calcification, NO periosteal reaction, hands most commonChondroid matrix (rings and arcs) in a small bone of the hand = virtually diagnostic. No treatment unless symptomatic
MetastasesOver 40 years. Lytic (most), blastic (prostate, breast), or mixed. Pedicle destruction on spine (winking owl)MOST COMMON malignant bone tumour in adults over 40. Usually multiple. Common primary: lung, breast, kidney, thyroid, prostate

Evidence Base

MRI for Local Tumour Staging

Prospective Study
Sundaram M, McGuire MH, Herbold DR • Radiology (1988)
Key Findings:
  • MRI accurately assessed intramedullary tumour extent in 97% of cases (vs 80% for CT).
  • MRI detected skip lesions (separate foci of tumour within the same bone) in 5% of cases that were missed by CT and radiographs.
  • MRI was superior for assessing soft tissue mass extent and neurovascular involvement.
Clinical Implication: MRI of the ENTIRE involved bone (including joints above and below) is essential for local staging — it detects skip lesions and guides surgical margin planning.
Limitation: MRI cannot distinguish between reactive marrow oedema and tumour involvement (may overestimate extent).
Source: Sundaram M et al. Radiology 1988;167(1):51-6

Lodwick Classification and Tumour Behaviour

Classification Study
Lodwick GS, Wilson AJ, Farrell C, Virtama P, Dittrich F • American Journal of Roentgenology (1980)
Key Findings:
  • Lodwick IA lesions (geographic, sclerotic margin) were benign in 95% of cases.
  • Lodwick II-III lesions (moth-eaten, permeative) were malignant in more than 90%.
  • The classification had high inter-observer reliability and predicted behaviour accurately.
Clinical Implication: The Lodwick classification is the most reliable radiographic predictor of tumour aggressiveness — it should be the FIRST assessment made when evaluating a bone lesion.
Limitation: Some aggressive lesions (like GCT) can appear geographic (Lodwick IB-IC), requiring clinical correlation.
Source: Lodwick GS et al. AJR 1980;134(1):19-26

Staging imaging evidence guides the assessment of bone tumours.

Biopsy Planning and Limb Salvage

Prospective Study
Mankin HJ, Mankin CJ, Simon MA • Journal of Bone and Joint Surgery (American) (1996)
Key Findings:
  • Improperly placed biopsies led to unnecessary amputation in 4.5% of cases and altered surgical planning in 18%.
  • Referral to a specialist musculoskeletal tumour centre before biopsy significantly reduced complications.
  • The biopsy tract MUST be excised en bloc with the definitive resection specimen.
Clinical Implication: Biopsy planning is CRITICAL — the biopsy must be performed by or in consultation with the surgeon who will perform definitive surgery to avoid contaminating tissue planes.
Limitation: Some centers now perform CT-guided core biopsy with excellent results — the key is communication between radiologist and surgeon.
Source: Mankin HJ et al. JBJS Am 1996;78(5):656-63

ABC Fluid-Fluid Levels on MRI

Imaging Study
Kransdorf MJ, Sweet DE • American Journal of Roentgenology (1995)
Key Findings:
  • Fluid-fluid levels on MRI were present in 95% of aneurysmal bone cysts (ABCs).
  • However, fluid-fluid levels were NOT specific for ABC — they were also seen in telangiectatic osteosarcoma (14%), GCT (8%), and chondroblastoma.
  • Telangiectatic osteosarcoma can closely mimic ABC on MRI — clinical and radiographic correlation is essential.
Clinical Implication: While fluid-fluid levels on MRI are highly suggestive of ABC, they are NOT diagnostic — telangiectatic osteosarcoma must be excluded, especially in metaphyseal lesions with aggressive features.
Limitation: Biopsy is essential for definitive diagnosis when the imaging differential includes telangiectatic osteosarcoma.
Source: Kransdorf MJ, Sweet DE. AJR 1995;164(3):573-80

Specific tumour patterns guide differential diagnosis and investigation.

Australian Context

In Australia, bone tumour management follows the multidisciplinary team (MDT) approach through specialised sarcoma units located in major metropolitan hospitals. The National Bone and Soft Tissue Tumour Registry and the Australian Sarcoma Group coordinate care and research. RANZCR guidelines mandate whole-bone MRI and CT chest as standard staging investigations before biopsy.

Australian orthopaedic guidelines emphasise referral to a specialist sarcoma centre BEFORE biopsy, consistent with international evidence that referral centre biopsy significantly reduces amputation rates and treatment complications. CT-guided core biopsy is the preferred technique at most Australian sarcoma centres.

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

EXAMINER

"An examiner shows you a radiograph of the distal femur in a 16-year-old boy with knee pain. The radiograph shows a mixed lytic and sclerotic lesion in the metaphysis with cloud-like mineralisation, cortical destruction, and a Codman triangle."

EXCEPTIONAL ANSWER
The most likely diagnosis is conventional osteosarcoma. The radiographic features that support this: (1) AGE: 16 years — peak incidence of osteosarcoma is 10-25 years (second decade growth spurt). (2) LOCATION: distal femoral metaphysis — the most common site for osteosarcoma (approximately 40% of cases occur around the knee). (3) MARGIN: mixed lytic and sclerotic with cortical destruction (Lodwick IC-II) — indicates an aggressive lesion. (4) MATRIX: cloud-like mineralisation — this represents osteoid matrix production (tumour bone), which is the hallmark of osteosarcoma. This cloud-like, dense, amorphous mineralisation is distinct from the rings and arcs pattern of chondroid matrices. (5) PERIOSTEAL REACTION: Codman triangle — aggressive periosteal reaction where the tumour has elevated the periosteum. The reactive bone at the triangle margin is NOT tumour tissue (do NOT biopsy it). I may also expect to see sunburst (spiculated) periosteal reaction. Staging imaging I would request: (1) MRI of the ENTIRE femur (from hip to knee, including both joints): to assess intramedullary tumour extent (critical for surgical margin planning), soft tissue mass size and relationship to neurovascular structures (popliteal vessels), skip lesions (separate tumour foci within the same bone — present in approximately 5% and mandate wider resection), and distal femoral physeal involvement (affects surgical approach). (2) CT chest: ESSENTIAL for pulmonary metastasis screening. The lungs are the most common site of metastasis from osteosarcoma. Present at diagnosis in 15-20% of cases. (3) Bone scan (technetium-99m MDP) or PET-CT: for skeletal staging — detecting other bone metastases. (4) Blood tests: alkaline phosphatase (elevated in osteosarcoma, correlates with tumour burden) and LDH. (5) REFERRAL to a specialist sarcoma centre BEFORE biopsy — biopsy tract placement must be planned with the surgeon who will perform definitive resection.
KEY POINTS TO SCORE
Osteosarcoma: metaphyseal, mixed lytic/sclerotic, cloud-like osteoid matrix, aggressive periosteal reaction
Codman triangle is reactive periosteum — NOT tumour tissue (do not biopsy it)
MRI of ENTIRE bone (hip to knee): intramedullary extent, skip lesions, soft tissue mass
CT chest: ESSENTIAL (pulmonary metastases present in 15-20% at diagnosis)
REFER to sarcoma centre BEFORE biopsy (poorly placed biopsy compromises limb salvage)
COMMON TRAPS
✗Not recognising the cloud-like matrix as osteoid (distinguishes from chondroid tumours)
✗Biopsying the Codman triangle (it is reactive periosteum, not tumour)
✗Not requesting MRI of the ENTIRE bone (skip lesions are missed)
✗Not referring to a specialist centre before biopsy
VIVA SCENARIOStandard

EXAMINER

"A 30-year-old woman presents with a lytic lesion in the proximal tibial epiphysis that extends to the articular surface. There is no matrix mineralisation."

EXCEPTIONAL ANSWER
The most likely diagnosis is a giant cell tumour (GCT) of bone. The radiographic features that support this: (1) AGE: 30 years — GCT has a peak incidence of 20-40 years (it is rare before skeletal maturity because it requires a CLOSED physis to extend into the epiphysis). (2) LOCATION: proximal tibial EPIPHYSIS extending to the articular surface — GCT characteristically involves the epiphyseal-metaphyseal region of long bones and ALWAYS extends to the subarticular surface. This subarticular location is the single most important diagnostic feature. The knee region (distal femur and proximal tibia) accounts for approximately 50-60% of GCTs. (3) MARGIN: lytic lesion — GCT is typically Lodwick IB-IC (well-defined but WITHOUT a sclerotic rim). The absence of a sclerotic margin reflects its locally aggressive biological behaviour. (4) MATRIX: NO matrix mineralisation — GCT is a non-matrix-producing tumour (no osteoid, no chondroid). This helps distinguish it from chondrosarcoma (rings and arcs) and osteosarcoma (cloud-like). (5) ECCENTRIC: GCT tends to be eccentric within the bone, creating an asymmetric expanded area. Additional features that may be present: cortical thinning (the lesion expands the bone from within), pathological fracture (occurs in approximately 10-15%), and soft tissue extension (in locally aggressive/recurrent cases). My investigation plan: MRI with contrast to assess the full extent, cortical integrity, and soft tissue component. CT chest and bone scan for staging. Biopsy for histological confirmation — GCT is graded histologically but all GCTs are considered potentially aggressive. The differential diagnosis includes: chondroblastoma (in OPEN epiphysis, younger patients, stippled calcification), subchondral degenerative cyst (different signal on MRI, no soft tissue mass), clear cell chondrosarcoma (rare, epiphyseal, chondroid matrix), and Brodie abscess (penumbra sign, clinical infection features).
KEY POINTS TO SCORE
GCT: subarticular (epiphyseal) location in CLOSED physis, extending to articular surface
Eccentric, lytic, NO matrix mineralisation, NO sclerotic rim (Lodwick IB-IC)
Peak age 20-40, knee region 50-60% of cases
Chondroblastoma: similar location but in OPEN physis (younger) with stippled calcification
MRI for extent, CT chest for staging, biopsy for confirmation
COMMON TRAPS
✗Not recognising the subarticular location as the key feature of GCT
✗Confusing GCT with chondroblastoma (physis must be CLOSED for GCT)
✗Expecting matrix mineralisation (GCT produces NONE)
✗Not mentioning the differential diagnosis
VIVA SCENARIOChallenging

EXAMINER

"An examiner asks you to describe the systematic approach to assessing a bone tumour on a plain radiograph."

EXCEPTIONAL ANSWER
I use the MAPLES systematic approach to assess bone tumours on radiographs. M — MARGIN (Lodwick classification): This is the FIRST and MOST IMPORTANT assessment. I classify the margin as: IA (geographic with sclerotic rim = benign in 95%), IB (geographic without sclerosis = low-grade malignant or aggressive benign), IC (geographic with ill-defined margin = intermediate), II (moth-eaten = moderately aggressive malignancy), or III (permeative = highly aggressive). This single feature is the best predictor of biological behaviour. A — AGE of patient: Age is a crucial narrowing factor. Under 5: Langerhans cell histiocytosis, neuroblastoma metastases, leukaemia. 5-15: Ewing sarcoma, osteosarcoma (10-25). 20-40: GCT, chondrosarcoma. Over 40: METASTASES and myeloma are far more common than primary bone tumours. The combination of margin and age significantly narrows the differential. P — PERIOSTEAL REACTION: The periosteal reaction reflects how FAST the tumour is growing. Solid, thick, uniform periosteal new bone = slow-growing (benign). Lamellated (onion-skin) = moderately aggressive (classic for Ewing). Sunburst (spiculated) = rapidly aggressive (classic for osteosarcoma). Codman triangle = tumour has broken through periosteum (aggressive) — the triangle is reactive bone, NOT tumour. L — LOCATION: Both within the bone (epiphysis, metaphysis, diaphysis) and within the skeleton (appendicular vs axial). Epiphysis: GCT (closed physis), chondroblastoma (open physis). Metaphysis: osteosarcoma, SBC, ABC, NOF. Diaphysis: Ewing, fibrous dysplasia, lymphoma. Flat bones: metastases, myeloma, chordoma (sacrum). Spine: metastases (posterior elements destroyed), haemangioma (vertebral body, corduroy pattern). E — EXPANSION and soft tissue: Is the bone expanded (ABC — eccentric blown-out shell), or is there cortical destruction with soft tissue mass (Ewing — large mass disproportionate to bone destruction), or is the lesion contained within the bone (enchondroma — no cortical breach)? S — STRUCK-THROUGH MATRIX (mineralisation): What is the tumour producing? Osteoid matrix = cloud-like, amorphous, dense (osteosarcoma, osteoid osteoma). Chondroid matrix = rings and arcs, stippled, punctate (enchondroma, chondrosarcoma). No matrix = purely lytic (GCT, myeloma, metastases, SBC). Ground-glass = fibrous dysplasia.
KEY POINTS TO SCORE
MAPLES: Margin, Age, Periosteal reaction, Location, Expansion, Struck-through matrix
Margin (Lodwick) is the MOST important feature — determines aggressiveness
Age narrows the differential: under 5, 5-25, 20-40, over 40 (metastases)
Periosteal reaction: solid (benign), onion-skin (Ewing), sunburst (osteosarcoma)
Matrix: cloud-like (osteoid), rings/arcs (chondroid), none (GCT/myeloma/mets)
COMMON TRAPS
✗Starting with the specific diagnosis rather than assessing the margin first
✗Not considering metastases in patients over 40 (most common malignant bone tumour)
✗Not describing the periosteal reaction pattern (key to aggressiveness)
✗Not distinguishing osteoid from chondroid matrix mineralisation

Bone Tumour Radiological Signs — Exam Day Reference

High-Yield Exam Summary

MAPLES Systematic Assessment

  • •Margin (Lodwick): IA (sclerotic = benign), IB-IC (no sclerosis), II (moth-eaten), III (permeative)
  • •Age: under 5 (LCH, neuroblastoma), 5-25 (Ewing, OS), 20-40 (GCT), over 40 (METASTASES)
  • •Periosteal: solid (benign), onion-skin (Ewing), sunburst (OS), Codman triangle (aggressive)
  • •Location: epi (GCT), meta (OS, SBC), dia (Ewing). Position: central vs eccentric
  • •Matrix: cloud-like = osteoid (OS), rings/arcs = chondroid (enchondroma/CS), none = GCT/mets

Classic Tumour Patterns

  • •Osteosarcoma: metaphyseal, cloud-like matrix, sunburst, Codman, age 10-25, around knee
  • •Ewing: diaphyseal, permeative, onion-skin, LARGE soft tissue mass, age 5-15
  • •GCT: subarticular epiphyseal, eccentric, lytic, NO matrix, Lodwick IB, age 20-40
  • •Enchondroma: central, rings/arcs, hands. Chondrosarcoma: same matrix but endosteal scalloping
  • •Metastases: most common malignant tumour over 40. Lytic (most), blastic (prostate/breast)

Staging Protocol

  • •MRI: entire involved bone (skip lesions), soft tissue extent, NV bundle
  • •CT chest: ESSENTIAL (pulmonary mets = most common site for primary bone tumours)
  • •Bone scan/PET-CT: skeletal staging (other bone lesions)
  • •Biopsy: REFER to sarcoma centre FIRST. Tract must be excisable en bloc
  • •Codman triangle = reactive periosteum — do NOT biopsy it
Quick Stats
Reading Time62 min
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